FAQ | Vegetables
Asparagus
Q. When I finish harvesting asparagus spears, how should I care for them during the rest of the year?
A. Allow the spears to fully develop into ferns. An occasional selective trimming or pruning can reduce the amount of top growth. Occasional light fertilizing and adequate moisture will help the plant develop sufficient top growth for good spear production.
Q. What causes my asparagus spears to get smaller and smaller each year?
A. This condition occurs in the warmer areas of the state. Spear production is primarily the result of food accumulated in the root system and previous year. If this amount of stored material is decreased because of high temperatures, especially in the fall or poor growing conditions, spears will be smaller the following spring. These conditions over a long period will gradually result in smaller and smaller spears each year.
Q. When should asparagus plantings be divided?
A. Divide asparagus roots during the winter after the tops have been removed. The tops will freeze and should be cut back as soon as spears begin to emerge in the spring. During this time the roots can be divided easily into individual plants for replanting as well.
Beans
Q. What causes my plants to bloom, but not set pods?
A. Excessive fertility often causes beans to bloom profusely but fail to set any pods. High temperature combined with low humidity can also cause beans not to set. Planted at the right time and without excessive fertility, most recommended varieties will produce a crop of high-quality beans. A light fertilizing after the first harvest will greatly increase subsequent yields and improve quality of later harvested beans.
Q. What causes garden beans to become tough, stringy, and fibrous?
A. This problem is commonly caused by high temperatures when the pods are forming. Low fertility and inadequate moisture can also contribute to this condition. To produce pods of high quality and flavor, plant beans when they will mature before temperatures become excessively hot.
Q. What is a broad bean?
A. Broad beans, also called fava, horse bean and Windsor beans, are not true beans. They are closely related to vetch and will grow in cool weather unsuited for green snap beans. Varieties commonly grown include Broad Windsor and Long Pod. They can be planted very early in the spring. In some cases, they will not produce in the heat of summer. The commonly grown varieties require from 85 to 120 days from seeding to harvest.
Q. The foliage of my beans turns yellow on top and forms a brown, dusty material on the bottom.
A. This is bean rust. It is caused by a fungus and can be controlled using recommended chemicals from the Extension Agents Handbook. Rust is associated with cool weather. Repeated applications are necessary. Begin at the first sign of rust.
Q. My bean foliage is distorted with a mottled pattern. The fruit is crooked and hard.
A. This is bean mosaic, a virus that is seed transmitted. Once it develops within a garden, it can be moved from one plant to another by aphids. Control this by using good quality bean seed, following an aphid control program in the garden, and removing disease plants.
Q. My beans came up to a good stand then began to die.
A. This is seedling disease of beans caused by a fungus, Rhizoctonia. Control for this disease includes a combination of practices. The first is to plant on a raised bed so the soil does not stay wet around these plants and will warm up faster. Refer to the Extension Agents Handbook for control of this disease. Apply the chemical to the seed furrow at planting time. In areas where this disease has been a problem, rotation is essential. The disease will be most severe during early spring.
Q. My beans are very stunted. When I removed them from the soil, I found large galls or swellings on the root system.
A. These are root knot nematodes. Root knot is a species of nematode which causes galls or swellings on plant roots. It restricts the uptake of nutrients from the root system to the foliage, resulting in a yellow and stunted plant. Root knot nematodes live in the soil and can survive on several weed and vegetable crops. For control, see OSU Fact Sheet Soil Solarization for Control of Soilborne Diseases.
Q. My beans appear to be very healthy. However, in examining the root system, I find that the roots have small galls attached to them.
A. These are nodules formed by nitrification bacteria. All legumes can fix atmospheric nitrogen in their root system. Do not confuse these nodules with knots caused by nematodes. The nodules, caused by nitrification bacteria, appear to be attached to the root system whereas knots caused by nematodes are enlarged areas of the root itself.
Q. My beans come up every year looking as if they are damaged. The leaves are curled and snarled. What is my problem?
A. The apexes or shoots of the leaves were damaged when they were very small by a tiny insect called a thrips. The thrips rasps the tissue of the leaf’s growing point causing it to “bleed” or secrete plant juices. The thrips then feeds on these juices. Most plants recover from this damage. Control thrips with a recommended insecticide according to label directions. Begin spraying when plants first emerge since most damage occurs then.
Beets
Q. Are beet tops good to eat?
A. Yes. Many people prefer the tops of beets to the enlarged roots. Beet tops are prepared much like other types of greens, such as collards or turnips, and have a distinctive flavor.
Q. Every time I plant beet seeds, more than one plant comes up from each seed. Is this normal or am I doing something wrong?
A. Table beet seeds are really clusters of single-seeded fruits grown together into a seedball or multiple fruit. It is common for several seedlings to come up from each seed planted. Single-seeded fruit of table beets are available but are not usually used by home gardeners. After your beet plants start coming up, they should be thinned to 1 inch between plants to allow for normal root development.
Broccoli
Q. What causes broccoli to flower almost immediately making the heads inedible?
A. High temperatures at heading time usually causes premature flowering and consequently reduces the quality and quantity of home-grown broccoli. Broccoli will flower quickly if it is forced to mature at temperatures much above 80°F.
Cabbage
Q. I often have trouble in getting my cabbage to form a head. What is wrong?
A. Cabbage and all members of the cabbage family, such as cauliflower and broccoli, require cool temperatures, adequate moisture, and high fertility to produce high yields of quality produce. Any condition which results in a stunting or stress on plants during the growing period can result in some extent of crop failure.
Q. What are “ornamental” cabbage and kale and are they edible?
A. Certain varieties of cabbage and kale produce decorative, non-heading plants with green or purple leaves and colorful white, cream, pink, red or purple interleaves. These are sold as flowering cabbage and can be used as attractive edging or for low accent plants in flower beds. Ornamental cabbage, like other members of the Cole crop family, matures best under cool temperatures. The leaves are edible but taste tough and strong. The plants are subject to the same insects and diseases as common cabbage.
Cantaloupe
Q. Why do my cantaloupes bloom and bloom, but seldom set any fruit?
A. Cantaloupes, like other vining crops such as cucumbers, pumpkins, squash, and watermelons, require pollination for fruit set. This means pollen must be transferred from the male blooms to the female blooms. Although cantaloupes are different than other vining crops because they have flowers which contain male and female parts as well as those which contain only male parts, pollination by bees is still necessary. High temperatures or high fertility can cause the cantaloupe to produce only male blooms, which results in poor fruit set. Nematodes can also cause small plants, profusion of blooms and no fruit set.
Q. Can cantaloupes cross-pollinate with other crops such as cucumbers, watermelons, squash or pumpkins?
A. Crossing between members of the cucurbit family is rare. If crossing occurs, it will not show up in this year’s fruit, but will be evident if seed is saved from these fruits to plant in next year’s garden. Many people relate off-flavored or strange-colored fruit with cross-pollination, but it is usually caused by environmental conditions or disease.
Q. What is the best way to determine when a cantaloupe is ready for harvest?
A. The cantaloupe is ready to harvest when the stem easily separates from the fruit. To avoid over-ripening, harvest cantaloupes before they naturally separate from the vine. The best way to check maturity of cantaloupes is to place your thumb beside the stem and gently apply pressure to the side. If the stem separates easily, the cantaloupe is ripe.
Q. Some years my cantaloupes are sweet and tasty and other years they have no flavor at all. What is wrong?
A. Cantaloupe flavor depends upon environmental conditions. High rainfall or excessive irrigation as the cantaloupes near maturity will adversely affect fruit flavor. Also, diseases which reduce the vigor of the plant and the leaves’ ability to produce sugar will affect fruit flavor. Maintaining the plants in a healthy growing condition and avoiding excessive watering near maturity will improve cantaloupe flavor. Lack of flavor is not caused by cantaloupes crossing with other vine crops, such as cucumbers.
Q. Can you save seed from this year’s crop of cantaloupes for planting in next year’s garden?
A. Yes, but this is not recommended. Do not save seed from any vine crops because some cross-pollinating can become evident when the seed are planted in next year’s garden. If you grow only one variety of cantaloupes and there are no cantaloupes in neighborhood gardens, seed can be saved for next year without producing off-type fruit. If hybrid varieties are used, you should not save seeds for next year’s planting.
Q. What is the difference between a honeydew and cantaloupe?
A. Honeydew melons are closely related to cantaloupes but ripen later. Most honeydew melons have white or green flesh and mature within 100 to 120 days after planting. Honeydew melons do not slip from the vine as cantaloupes do and are mature when they become creamy to golden yellow in color and blossom-end softens slightly.
Carrots
Q. I have planted carrots several times with no luck. Why won’t they come up?
A. Do not plant them too deep. Sow the seeds on top of the bed and gently rake them in, covering the seed only about 1/4 inch. Germination will increase as soil temperatures decrease. Keep your planting area moist. Don’t crust or harden the soil on top of the bed with direct sprays of water.
Q. What causes the top of my carrots to be green rather than orange?
A. Greening of the top of the carrot is caused by sunlight. Heavy rain can wash away the soil from carrot roots exposing them to the sun. An off flavor is often associated with this green color. Remove the tops before consuming or canning the carrots.
Q. Why are my garden carrots short and stumpy instead of long and slender like those in grocery stores?
A. The problem is probably variety selection. There are varieties, which are genetically short and thick, that are recommended for home gardening. Those sold at grocery stores are the Imperator type and inherently long and slender. Carrot length can be affected by excessive moisture during growth.
Q. What causes my home garden carrots to be tasteless, woody and often bitter instead of sweet and tender?
A. These problems are associated with growing and environmental conditions during the maturing period. Carrots grow best and develop highest sugars when temperatures are between 40° and 80°F. The best carrots are planted in fall for early winter harvest. Carrots are cold hardy but should be planted so they mature before temperatures drop below 20°F as damage or death can occur.
Cauliflower
Q. I am growing cauliflower for the first time. I read that it must be blanched to reach its best quality. What is blanching? When and how is it done?
A. Blanching of cauliflower means protecting the heads from sunlight. Unblanched heads will be yellowish green while blanched heads are pure white. When the head begins to enlarge, pull the outer leaves over the head, and tie them with a rubber band or soft twine.
Q. I’ve seen self-blanching varieties advertised in many catalogues. What does this mean?
A. The leaves of these types grow over the curds, saving you the trouble of tying them up. Romanesco cauliflower (sometimes called Romanesco broccoli) has beautiful, pointed, green curds that look like little towers. Purple cauliflower, which turns green when cooked, is also available.
Collards
Q. When harvesting collard greens, should you harvest only the older, mature leaves or pull up the entire plant?
A. Although collard greens can be harvested both ways, maximum yields result if the leaves from the bottom of the plant are harvested before they become too old. The first harvest generally occurs when the plants are about 60 days old.
Corn
Q. Should garden corn be planted in several short rows rather than in one or two long rows?
A. Yes. Corn is pollinated by wind-borne pollen. Planting corn in blocks rather than in long rows makes it easier for the plants to pollinate one another during tassling.
Q. Should the suckers or side shoots which emerge near the ground level on sweet corn be removed?
A. This is not necessary although experienced gardeners feel removal of the suckers will result in larger, high-quality ears. The suckers should be snapped off while they are small.
Q. How long does it take for most sweet corn varieties to produce edible ears?
A. Most sweet corn varieties on the market today will mature between 65 to 90 days after seeding. Maturity rate will vary greatly from year to year and from season to season depending on temperatures.
Q. How come some years sweet corn is sweet and tasty and other years it lacks the desired flavor?
A. The flavor of sweet corn is highly dependent on weather conditions. If it rains within a week of harvest time, the flavor of sweet corn is often greatly diminished. Also, if the corn matures during high daytime temperatures as well as high nighttime temperatures, the sugar levels of sweet corn will be low, and flavor will be disappointing. The sugar in sweet corn is converted to starch rapidly even under optimum storage conditions so the corn should be cooked soon after harvest.
Q. Is there a best time of day to harvest sweet corn?
A. Experienced sweet corn gardeners recommend harvesting corn during the early morning. This ensures the sugar will be at its highest level if the corn is mature, but not overripe.
Q. How often should sweet corn be fertilized to produce high yields of good quality corn?
A. Sweet corn should be lightly fertilized prior to planting. It should be fertilized again when the plants are approximately 4 inches tall and when they are 8 to 10 inches tall.
Q. What is meant by advertisements in catalogs referring to “Super Sweet” varieties of sweet corn?
A. Newly developed “Super Sweet” hybrid varieties may contain up to 40 percent more sugar than some of the standard varieties. Super sweet hybrids carry a genetic factor which results in a high sugar content. The super sweet character is lost if the corn is pollinated by ordinary sweet corn or field corn so the super sweet hybrids should be planted away from any other type of corn.
Q. What is the difference between roasting ears and sweet corn?
A. To most Oklahomans, roasting ears are field corn harvested at an immature stage. Some people prefer field corn because the ears are larger, and the corn is not as chewy. There is no comparison in flavor between sweet corn and roasting ears if the sweet corn is grown under proper conditions, harvested at the right stage of maturity, and handled properly between harvest time and cooking time.
Cucumbers
Q. I have planted squash and cucumbers in my garden. Do I need to worry about cross-pollination and resulting off-type fruits?
A. Planting cucumbers along with squash in your garden will not result in off-flavor fruit. Odd-tasting fruit from vine crops is not the result of crossing between plants such as cucumbers, cantaloupes, and squash. These crops will not normally cross. If they did, the results of this cross would not show up until the seeds from this year’s fruit were planted in next year’s garden.
Q. What causes my cucumbers to often be misshapen and gourdy-looking?
A. Probably poor pollination. Improper pollination caused by lack of insects or pollen killed by hot temperatures can cause misshapen fruit. Moisture stress during development can also misshape fruit. Pollination did occur or the fruit would not be present.
Q. Why do my cucumbers bloom without setting fruit?
A. This is a pollination problem. Cucumbers have male and female blooms and for proper fruit set, the pollen must be transferred from the male to the female blooms. This is usually done by pollinating insects, primarily honeybees. If pollen transfer does not take place, fruit will not set.
Q. How do you tell the difference between the male and female cucumber bloom?
A. Female blooms have small immature cucumbers located directly behind the petals. Male blooms do not have immature fruit.
Q. Is a gherkin simply a small pickling cucumber?
A. No. Gherkins, also called West Indian or Burr cucumbers, produce small, exceptionally spiny fruit used exclusively for pickles. The culture of gherkins is like common pickling cucumbers except the plants are smaller and require less space.
Q. The foliage of my cucumbers is developing brown spots which drop out leaving a tattered effect.
A. This is Anthracnose or Alternaria leaf spot. These diseases develop around the crown of the plant and can be controlled with fungicides recommended in the Extension Agents’ Handbook. Repeated applications will be required at 10 to 14 days.
Q. The underside of my cucumber has a spot on it.
A. This is belly rot, caused by the soilborne fungus Rhizoctonia. It can be controlled by caging the cucumber or mulching so the fruit does not contact the soil. Belly rot can also be reduced by growing cucumbers on well drained soil and not applying large amounts of water during the harvest period. Chemical control has not proven satisfactory for the control of this problem.
Lettuce
Q. Why did my lettuce taste so bitter and start to grow tall so quickly?
A. Most home garden lettuce, especially the Bibb variety, goes to seed quickly in high temperature, long-day conditions. It quickly develops a bitter flavor in hot weather. Buttercrunch, Saladbowl, Ruby and Romaine tolerate these adversities more than other varieties and remain sweet and tender longer.
Okra
Q. Can okra plants be pruned during late summer or early fall for additional production until the first killing frost?
A. Yes, but it might be best to simply make a mid-summer planting instead of pruning off spring-seeded plants. When pruned, the plants will develop a bush rather than a single stalk which usually makes harvesting difficult. Pruning should be done 80 to 100 days before the first fall frost is anticipated allowing the plants time to produce additional pods.
Q. Can seed from this year’s okra be saved for next year’s planting?
A. Yes. Okra is a self-pollinated crop and seed can be saved from one year’s garden for the next. Toward the end of the season allow some of the pods to remain on the plant and harvest them when they become fully mature and almost dry. If you allow okra pods to remain on the plant and fully mature, subsequent production is greatly curtailed.
Q. Small drops of liquid are oozing from various areas on the leaves and stems of my okra plants. What causes this?
A. You are describing natural secretions from the okra plant through glands on the leaves and stems. This is a natural process of the plant and causes no damage.
Q. What causes my garden okra to fail to grow properly when planted in the early spring?
A. Maybe it was planted too early. Okra should be planted 3 to 4 weeks after the last spring frost to produce an abundant supply of fresh garden okra. If planted before soil temperatures warm up and before night temperatures average above 50°F, okra fails to grow properly. Okra is a close relative of cotton and should be planted about the same time cotton is planted.
Q. My okra did not grow properly last year. When I removed it at the end of the season, the roots were damaged by galls and swellings.
A. The damage was a result of root knot nematodes. For control, see OSU Fact Sheet EPP‑7640, Soil Solarization for Control of Soilborne Diseases.
Q. What causes okra pods to be crooked and bent rather than straight?
A. This could be caused by insects feeding on the pods. Certain sucking insects, such as stinkbugs and leaf-footed bugs, inject chemicals into the pods causing the pods to stop or slow down growth in that area. The other side, which is growing normally, results in a curved or bent pod. The pods can still be eaten. No control is necessary unless the bugs are still feeding on the plants.
Q. I have ants all over my okra. Do they hurt the plants?
A. Ants do not hurt your okra plants. Ants visit okra plants to get honeydew produced by sharpshooters, aphids, or other sucking insects. Get rid of the sucking insects and the ants will leave.
Onions
Q. Is it necessary to remove the garden soil from around my onion bulbs in the spring to make large bulbs?
A. Absolutely not. Bulbing of onions is controlled by variety, temperature, and length of day. The onion will bulb when the required conditions are met. Removing soil around the base of the plant will not increase bulbing, although it appears to because the bulbs are visible. This operation may do more damage than good, especially to white varieties of onions. Removing the soil from around white onions results in sunburning, which turns the top of the bulbs green.
Q. What varieties of green onions grow well in Oklahoma?
A. The term green onion describes an immature onion. Even the large bulb onions such as Grano or Granex can be harvested immature and used as green onions. Some gardeners who seed these varieties of onions directly in their garden selectively thin them as they grow and use the thinning as green onions. Evergreen Bunching and Beltsville Bunching varieties will not form bulbs but produce clusters of 4 to 8 slender, white onion stalks. The shallot, a multiplier-type onion with a distinct flavor, is also used as a green onion.
Q. What is the difference between a set and a transplant?
A. Although many gardeners use these terms interchangeably, there is a difference. An onion set is a small bulb, 1/2 to 1 inch in diameter. It is produced under conditions which rapidly produce a small bulb which, when planted, will grow a larger bulb. An onion transplant is a plant between 8 to 10 weeks old which has not gone through the bulbing process, and if planted at the right time will produce large bulbs.
Q. What is a bunching onion?
A. Several types of onions are used as green bunching onions. Evergreen White Bunching and Japanese Bunching are frequently planted varieties of this type. They may be planted from seed, sets or transplants. Bunching onions are generally classed as multipliers because they propagate themselves. They are cold resistant and can be grown during the winter months. They will not bulb and are harvested as needed, using both the root and the tops.
Q. What is a shallot?
A. A shallot is a member of the onion family which lives for many years and is grown for its mild, garlic-flavored roots, made up of segments called cloves. The plants will grow to be about 18 inches tall and often bear white or violet flowers in early summer.
Q. Every year I buy onion plants to set out in the spring in my garden, some years they make nice size bulbs and other years they don’t. Why?
A. There is no simple answer to this commonly asked question. First, obtain varieties which will bulb in your particular area of the state. Always buy plants about the size of a lead pencil. Larger plants will not produce earlier or produce larger bulbs. Generally, a large onion plant will produce a seed stalk after planting instead of forming a large bulb. Always set the plants in your garden at the right time for your area.
Q. Should I break over the tops of my onion plants to get a larger bulb?
A. Breaking over the tops of onion plants will not increase bulb size but can prevent bulb enlargement. Onion bulbs increase in size as sugars manufactured in the top are translocated to the bulb. If the tops are broken, this process stops preventing further bulb enlargement. This question comes up often among gardeners interested in growing large onions.
Q. What is the difference between green onions and leeks?
A. A leek has a much milder flavor than an onion. The term scallion describes leeks and green onions.
Q. What causes my bulb onions to send up flower stalks?
A. Flowering of onions can be caused by several things, usually temperature fluctuation. An onion is classed as a biennial which means it usually takes 2 years to go from seed to seed. However, this condition is triggered by temperatures. If an onion plant is exposed to alternating cold and warm temperatures resulting in the onion plant going dormant, resuming growth, going dormant and then resuming growth again, the onion bulbs prematurely flower or bolt. Flowering can be controlled by planting the right variety at the right time. Use only transplants that are pencil-sized or smaller in diameter.
Q. Should I remove the flower stalks from my onion plants?
A. No. Once the onion plant has bolted or sent up a flower stalk, there is nothing you can do to eliminate this problem. The onion bulbs still will be edible, but probably will be smaller. Use these onions as soon as possible because the green flower stalk which emerges through the center of the bulb will make storage almost impossible.
Q. After harvesting, what is the best way for me to store my onions?
A. Onions should be stored in a relatively cool, dry place. Some mild and sweet onions will not store as long as northern, more pungent varieties. Maximum length of storage of onions will run from 2 or 3 months. Allow your onions to fully mature in the garden before harvesting. Maturity is indicated by the fall of the top of the onion plant. After the tops have fallen, pull and dry the onions in the garden for several days. Some gardeners prefer to pull the onions up partially which allows the onions to dry while still in the ground. After drying, remove the roots and the top, leaving about 3/4 to 1 inch of the neck to seal and prevent entrance of decay organisms.
Peppers
Q. Why do my pepper plants often bloom, but fail to set fruit?
A. Peppers, like tomatoes, are sensitive to temperature. Most peppers will drop their blooms when daytime temperatures get much above 90°F in combination with night temperatures above 75°F. They will also drop their blooms in the early spring if temperatures remain cool for extended periods. Hot peppers, such as jalapenos, withstand hot weather fairly well and can often produce fruit through the summer. Optimum temperatures fall between 70° and 80°F for bell-type peppers and between 70° and 85°F for hot varieties.
Q. If you plant hot peppers beside sweet peppers, will the sweet pepper plant produce hot fruit?
A. Absolutely not. Pepper flowers are self-pollinated, although occasionally cross-pollinate. However, the result of this crossing will appear only if seed is saved from this year’s crop and planted next year. It will not result in off-flavor or differences in fruit characteristics of this year’s crop.
Q. Is there any difference in taste or nutritive value between green peppers and those that mature and turn red?
A. Peppers that are allowed to mature and ripen entirely, from green to yellow to red, are higher in vitamin content, especially vitamin A. There is little difference in taste although there is a considerable difference in texture caused by the ripening process.
Q. Can I save seed from this year’s pepper crop for planting in my next garden?
A. Yes. Peppers are self-pollinated and consequently will breed true if seed is saved from this year’s garden for planting in next year’s garden. Although an occasional cross-pollination will occur, this is generally not a problem. Do not save seed from hybrid pepper plants as these will not breed true and will result in plants exhibiting characteristics different than the desired hybrid.
Potatoes
Q. I used potatoes purchased at the grocery store as seed for planting and they rotted without sprouting. Why?
A. Many potatoes sold for fresh market consumption have been treated with chemicals to prevent sprouting in storage. These chemicals will also prevent sprouting after planting. Another possibility is that the potatoes that you purchased in the store were from this year’s crop and had not been stored properly to break the rest period. Potatoes have a rest period which must be broken before the seed will sprout. Cool temperatures or extremely warm temperatures can break the rest period and allow potatoes to sprout. Next time plant certified seed that has been properly stored to induce sprouting.
Q. Can I save the small potatoes from my spring crop for planting in my fall garden?
A. Yes. This is commonly done because good seed potatoes are scarce in the fall. Sometimes the potatoes saved from the spring garden fail to sprout when planted in the fall because of natural dormancy in newly harvested potatoes. Considerable controversy exists as how to handle these potatoes to break the dormancy and enable them to sprout when planted. One recommended procedure for breaking the dormancy includes harvesting the potatoes and placing them in a cool storage area, preferably in the range of 50°F until about 3 to 4 weeks before the anticipated fall planting date. At that time, remove the small potatoes and maintain them at normal environmental conditions until planting time. Maintaining the seed potatoes at a high humidity during this time by covering them with moist burlap bags or some similar material will also initiate sprouting. The small potatoes should be planted whole and not cut to prevent rotting.
Q. What size piece should seed potatoes be cut into?
A. Each seed piece should contain at least 2 to 3 “eyes”. Research has shown that the best size seed piece weighs approximately 2 ounces. If seed potatoes are expensive or scarce, the size can be reduced although each piece must contain at least one eye.
Q. Sometimes my potatoes or the potatoes I see at supermarkets have a green color. Are these potatoes poisonous?
A. Potatoes that exhibit a green color contain a substance known as Solanine. This substance, if consumed in extremely large quantities can cause severe illness or death. This greening of potatoes is caused by exposure to light during the growing period or excessive exposure to artificial lights at grocery stores or supermarkets. In the garden, this is most common after heavy rains which uncover potatoes near the surface exposing them to sunlight.
Q. I have some seed potatoes left from my spring garden. Would it be all right to eat them?
A. No. Potato tubers purchased for seed purposes should not be eaten. Frequently, such tubers have been chemically treated. Like all treated seeds, seed potatoes should not be fed to humans or animals.
Q. My potato plants produced small tomatoes this year. I planted them next to my tomatoes. Could they have crossed or have my potatoes mutated?
A. The fruit on the potato plant is the fruiting structure of the potato plant. The potato and tomato belong to the same botanical family and have similar growth characteristics. The potato flower looks very much like the tomato flower and is pollinated and fertilized identical to the tomato flower. The fruit will mature if the plant is left long enough. Your potato and tomato plants have not cross fertilized.
Pumpkins
Q. Will pumpkins cross with squash, watermelons or cucumbers resulting in off-type fruit?
A. Varieties of the true pumpkin cross readily with each other, but this crossing will not be apparent unless seed are saved from this year’s fruit and planted for next year. Pumpkins will not cross with varieties of true squash. All varieties of “summer squash” are in reality true pumpkins and will cross readily with each other and with other pumpkins. If you grow both summer squash and pumpkins in your garden, you should not save seed for planting in next year’s garden.
Q. Will it help to remove the tips of my pumpkin vines late in the season to encourage fruit size?
A. The tips of vining pumpkins may be removed about 45 days prior to the anticipated first fall frost to discourage plants from further spreading. This practice will generally encourage larger fruit and will not harm production as any additional fruit which might set after that time will not ripen before the first killing frost of the fall.
Radishes
Q. What causes my radishes not to bulb?
A. Radishes will fail to bulb for several reasons. Probably, they are not properly thinned and are growing too close together. Radishes should be seeded 2 to 3 seeds per inch and thinned when they are about 1 to 2 inches tall to a spacing of 1 inch apart. Radishes will also not bulb properly when forced to mature during temperatures above 80° to 85°F.
Q. Sometimes my radishes have a hot, bitter flavor. What is the problem?
A. Off-flavored radishes are caused by planting at the wrong time or poor cultural practices such as low fertility or low moisture resulting in slow growth. For highest quality, radishes should grow fast. Fast growth can be stimulated by adequate fertility and maintaining the soil in a good moisture condition. If radishes are too old, they taste hot.
Q. What causes roots of radishes to crack?
A. This is usually caused by harvesting the radishes too late. Cracking is caused by fluctuations in moisture which cause the root to swell rapidly and crack, especially near maturity.
Q. Are the leaves of radish plants edible?
A. Radish leaves are not poisonous and can be consumed although they have a strong, bitter flavor. There may be some dishes or some methods of preparing radish leaves, which would make them more palatable, but for the most part they lack a desirable flavor.
Spinach
Q. Should spinach be harvested by removing the outer, older leaves or by pulling the entire plant?
A. This depends on whether it is a spring or fall planted crop. In the spring, spinach will go to seed quickly so the best harvesting method is to pull the entire plant. When planting in early fall for winter harvesting, harvest the outer leaves and allow the plant to continue to grow and produce additional foliage.
Squash
Q. Each year my squash blooms profusely, but seldom produces any squash to eat. What is wrong?
A. Squash plants produce male and female blooms. For fruit to set, pollen must be transferred from the male to the female bloom. Pollinating insects, mostly bees, carry out this important job resulting in fresh squash for the kitchen. When treating the garden for insects and diseases spray or dust during the late afternoon to avoid killing bees. Nematode infestations can also cause this problem. Check roots for galls.
Q. Will squash cross with other vine crops in my garden such as watermelons and cucumbers?
A. No. Squash will cross-pollinate with other types of squash, for example yellow squash with green squash, but they will not cross-pollinate with cucumbers, watermelons, or cantaloupes. This cross-pollination will not result in off-flavored or off-colored fruit from this year’s garden, but if seed are saved for planting next year the result will be a combination. If yellow squash crosses with a zucchini squash and you plant the seed, the new plant will have the characteristics of both.
Q. Can seed be saved from this year’s squash crop for planting in next year’s garden?
A. Yes, but this is not a recommended practice. Because squash has male and female blooms and need bees for pollination, seed saved from this year’s crop probably will not breed true when planted next year. This is especially true if you are growing more than one type of squash. If you are only growing one type of squash and there are no other types of squash in the area then seed can be saved with a fairly high degree of genetic purity. If you are growing hybrid squash, do not save seeds as they will not breed true.
Sweet Potatoes
Q. When should you bed out sweet potato roots for slip production?
A. To produce slips, sweet potato roots should be laid on their sides in hotbeds about a month before the nighttime temperatures stay above 60°F. Cover the sweet potato roots with 2 inches of moist sand and keep the hotbed between 75° and 80°F. When the sprouts develop, remove them with a twisting tug. Additional transplants (slips) will form from the bedded sweet potatoes if left in place.
Q. Is there a difference between sweet potatoes and yams?
A. Yes and no. In the southern United States, some sweet potatoes are advertised as yams, for example, Louisiana Yams. However, these are all sweet potatoes with the scientific name Ipomoea batatas. The true yam, which is native to tropical regions is an unrelated plant with the scientific name Dioscorea batatas. The true yam is also called a Chinese Yam or Chinese Potato. True yams are not grown as food crops in the continental United States.
Swiss Chard
Q. Is Swiss chard related to beets? The leaves look and taste somewhat alike.
A. Swiss chard (or just “chard”) is a bulbless beet grown for its leaves and stems. Apart from being delicious, especially when steamed and eaten with butter and lemon juice, chard is a garden favorite because it is so easy to grow. The green and red leaf varieties are equally tasty.
Q. Is it better to pull up whole plants or harvest chard leaf by leaf?
A. Cut the outer leaves at the base, rather than pulling up the plant by the roots. You can cut the inner leaves, too, if you like the small, tender ones. The plants will take longer to come back this way but come back they will.
Tomatoes
Q. My tomato plants look great. They are dark green, vigorous and healthy. However, flowers are not forming any fruit. What is the problem?
A. Several conditions can cause tomatoes to not set fruit. Too much nitrogen fertilizer, nighttime temperatures over 70°F, low temperatures below 50°F, irregular watering, insects such as thrips, or planting the wrong variety may result in poor fruit set. Any of these conditions can cause poor fruit set, but combinations can cause failures.
Q. Are there really low-acid tomato varieties?
A. There are some varieties that are slightly less acidic than others, but this difference is so slight that there is no real difference in taste or how the tomatoes should be processed. Some yellow-fruited types are slightly less acidic than the normal red varieties, but not enough to make any difference. Research conducted by the USDA indicates that all varieties available to the home gardener are safe for water bath processing if good quality fruit are used. Flavor differences which exist between varieties are not because of differences in acid content, but balances of the sugar to acid ratio.
Q. What causes a tomato to crack? Is there anything I can do to prevent it?
A. Cracking is a physiological disorder caused by soil moisture fluctuations. When the tomato reaches the mature green stage and the water supply to the plant is reduced or cut off, the tomato will begin to ripen. At this time, a cellophane-like wrapper around the outer surface of the tomato becomes thicker and more rigid to protect the tomato during and after harvest. If the water supply is restored after ripening begins, the plant will resume translocation of nutrients and moisture into the fruit. This will cause the fruit to enlarge, which in turn splits the wrapper around the fruit and results in cracking. The single best control for cracking is a constant and regular water supply. Apply a layer of organic mulch to the base of the plant. This serves as a buffer and prevents soil moisture fluctuation. Water plants thoroughly every week. This is especially important when the fruits are maturing. Some varieties are resistant to cracking, but their yield and quality are less than other varieties.
Q. What causes tomato leaves to curl?
A. The exact cause of this tomato leafroll is not fully known. Tomato leafroll appears around the time of fruit setting. The leaflets of the older leaves on the lower half of the tomato plant roll upward. This gives the leaflets a cupped appearance with sometime even the margins touching or overlapping. The overall growth of the plant does not seem to be greatly affected and yields are normal. This condition appears to be most common on staked and pruned plants. It occurs when excessive rainfall or overwatering keeps the soil too wet for too long. It is also related to intensive sunlight which causes carbohydrates to accumulate in the leaves.
Q. Do products which are supposed to aid in setting tomatoes really work and if they do, how should they be used?
A. These hormonal products are designed to substitute for natural pollination. These products work better when tomatoes are failing to set because of too cool temperatures. Most of the fruit set problems in Oklahoma are caused by too high temperatures. Also, tomatoes which set after use of these products will be puffy and seedless.
Q. What is the plant advertised as a tree tomato?
A. The tree tomato is a member of the nightshade family. The regular tomato belongs to the same plant family but is a different species. The tree tomato has the scientific name Cyphomandra betacea. Like the true tomato, it is a native of Peru. It is grown in market gardens there and in several subtropical countries including Brazil and New Zealand. The tree tomato is woody, grows from 8 to 10 feet tall, bears fruit 2 years after seeding and may continue to bear for 5 to 6 years. They are not winter hardy and would need to be taken inside over winter. Fruits of the tree tomato are oval, about 2 inches long and change from greenish purple to reddish purple when fully ripe. The fruits are low in acid and the flavor is moderately agreeable. Some varieties of the tree tomato produce bright, red fruits. The fruits can be used in stew or preserves after the tough skin and hard seeds are removed.
Q. Should you allow tomatoes to become fully ripe and red on the vine before harvesting?
A. Generally, yields will be increased by harvesting the fruit at first blush of pink instead of leaving them on the plant to ripen fully. A tomato picked at first sign of color and ripened at room temperature will be just as tasty as one left to fully mature on the vine. Picking tomatoes before they turn red reduces damage from birds.
Q. If tomatoes are picked green or before they are fully mature, how should they be handled to insure proper ripening and full flavor?
A. Never refrigerate tomatoes picked immature. Place them in a single layer at room temperature and allow them to develop full color. When they are fully ripe, place them in the refrigerator where they will store for several weeks. Those handled in this manner will be of high quality and full flavor.
Q. Can I propagate tomatoes for the fall garden from existing vines?
A. If necessary, use suckers or layering (cover with soil until roots appear) on existing vine. Do this several weeks before the recommended transplanting date for fall tomatoes and use early tomato varieties.
Turnips
Q. What causes turnips to fail to make large roots?
A. Like radishes and other bulbing crops, crowded turnips will fail to enlarge. Turnips also require a moderately fertile soil and adequate moisture to grow large, fleshy roots. For good size bulbs, space turnips 2 to 3 inches apart; plant in the spring as soon as the ground can be worked. For a fall crop, plant when daytime temperatures average below 80°F.
Q. Are there varieties of turnips grown just for the tops and not their enlarged roots?
A. Yes. The varieties Crawford and Shogoin are grown primarily for their tops and usually fail to make large, high-quality roots.
Q. What causes my turnip greens to often have a bitter and pungent flavor?
A. Conditions which result in slow growth or stress of the turnip plant will often cause the leaves to have a bitter, off-flavor. This condition is prevalent when turnip leaves mature under high temperatures combined with unfavorable growing conditions.
Watermelon
Q. Do watermelons readily cross with other vine crops resulting in off-flavor and poor-quality fruit?
A. Watermelon varieties readily cross with each other watermelon and with the wild citron, but crossing will not be apparent unless seeds are saved to plant another year. Watermelons will not cross with cantaloupes, cucumbers, pumpkins, squash or cushaws. Off-flavor or odd-shaped fruit is generally caused by growing conditions and not cross-pollination.
Q. What causes watermelon plants to fail to set fruit?
A. Poor fruit set in watermelons is usually because of poor pollination. The watermelon plant produces male and female blooms and bees are necessary to transfer the pollen from the male to female bloom. Common causes of poor fruit set include lack of bees for pollinating or cool, wet weather which slows bee activity during bloom.
Q. What causes the end of the watermelon fruit to turn black and rot?
A. Watermelon fruits are affected by blossom end rot just like tomato fruit. In general, this condition occurs on watermelon fruit if the plant loses excessive moisture through an unusually dry period. Ability of the plant’s roots to keep up with water loss by the plant results in desiccation and blackening of the blossom end of the fruit. Prevent blossom end rot by maintaining adequate moisture conditions to the plants, especially as the fruit matures.
Specialty Crops
Q. Can the leaves of Brussels sprouts be eaten?
A. Yes. They are prepared much like collards. Harvest only the young, tender leaves as mature leaves often have an off flavor.
Miscellaneous
Q. Are there any vegetables that I can grow in the shade?
A. Lettuce needs at least a half day of full, though not intense sunlight, but it benefits from midday shade during hot spells. Asparagus and rhubarb will tolerate minimal shade after their growth in early spring. Cucumbers can produce in partial shade. Vegetables that survive with minimal sunlight (5 to 6 hours per day) are beets, carrots, cauliflower, radishes, spinach, and Swiss chard. Other vegetables prefer 6 to 8 hours.
Q. At what time of day should I water?
A. Early morning watering is best, although evening watering is good too, provided there is enough time for leaves to dry before nightfall. Although midday watering is not harmful to plants, it is wasteful since much water evaporates in the heat and sun.
Q. How can I know when to water?
A. Observe your plants. If they are wilted in the morning or the ground is dry 2 to 4 inches deep, it is time to water (A dry top inch will do no harm and is actually desirable for older plants). Don’t hose down the garden because you see your plantings wilting in the heat of day. By sprinkling instead of deep watering, you will encourage plants to develop weak, surface root systems that need constant watering. These plants will suffer badly should even one of these watering be missed on a hot day. A general rule is that vegetables should get the equivalent of 1 inch of water each week.
Q. For how long should I water?
A. Avoid depending on hand watering with the faucet turned up all the way. The top inch or so of soil will get well saturated, but much water will run off the surface to the edges of the beds instead of deep into the soil where it belongs. It is much better to use a soaker or sprinkler hose, sprinklers, or a drip irrigation system and to leave the water running slowly for a long time, moistening the soil thoroughly 4 to 6 inches deep. After watering, keep the moisture in by laying down as heavy a mulch as possible without smothering plants. If you use a sprinkler, set an empty can in the path of its spray to determine how long it takes for an inch of water to accumulate.
Q. Should my planting rows run north and south or east and west?
A. More important than compass orientation, a garden’s rows (or rectangular planting beds) should run along a slope rather than up and down it, and tall-growing plants should not shade other plants.
Q. How can I make sure my compost pile heats up?
A. Add plenty of nitrogen, stir the heap every week or so to incorporate oxygen (by sinking pipes into the compost and rocking them in a circular motion), and make sure the heap never dries out. It should be moist, but not soggy.
Q. Is it necessary to age fresh manure before using it?
A. Yes, both to keep it from burning plants and to kill the weed seeds in it.
Q. What is seed inoculant and how should I use it?
A. Many gardeners coat seeds of the legume family (beans and peas) with inoculant before planting. Inoculant is a powder that encourages increased numbers of nitrogen-fixing bacteria around the plant roots. Just before planting, moisten the seeds with water, sprinkle the inoculant powder over them in the amount called for on the package and mix well. Store unused inoculant in the refrigerator and discard it after the date on the package. Be sure to buy an inoculant powder that is specified for the legume you are planting.
Q. What is succession planting?
A. This is a technique whereby a second (or even a third) crop is planted in a bed as soon as possible after a harvest. With good planning, in some areas it may be possible to get three crops by beginning the season with a cool-weather crop, following it with a warm-weather crop, and succeeding that one with another cool-weather crop. Even very small gardens can produce impressively large amounts of food with this method.
Q. What can I use to protect plants against fall frosts?
A. Cloches, mini-greenhouses, and floating row covers will protect against light frosts. With a 1 ½ to 2 foot mulch of straw or dried leaves and snow cover, plants such as kale and other members of the cabbage family, as well as many root vegetables, should survive well into winter. Be sure to mark the location of root vegetables so that you can find them under the snow. In some cases, you may wish to invert bushel baskets over your plants and then cover them with mulch.
Q. Is there anything I should do to ready the garden for winter after I have taken the last crop of the season from it?
A. Remove any tough, thick, fibrous plant material, chop it up, and throw it on the compost heap. Turn all remaining crop residue into the soil, spread a layer of manure on the soil, and sow a cover crop, or apply a 1-foot-deep mulch of straw or leaves. If you leave the ground bare through the winter, heavy rains may erode the soil; a cover crop or mulch will add valuable organic matter and nutrients to your soil, improving both its texture and its fertility.
Q. Won’t crop residues that are turned into the soil harbor pests and diseases?
A. No. When you turn them under the soil, they decompose, destroying the pests that were on them and many kinds of diseases as well. Exceptions are eggplant and tomatoes – burn or dispose of any diseased stems and leaves of these plants.