Horticulture
OSU Extension is dedicated to bringing you the latest research-based information for your lawn, garden, landscape and other horticulture concerns. Visit us for one-on-one help in a variety of areas, including gardening, tree planting, plant selection, pest control and home pesticide use.
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Soil, Water and Forage testing
The OSU Soil, Water and Forage Analytical Laboratory works in conjunction with OSU Extension. You can drop off your soil samples at the OSU Extension Office Monday - Friday, 8 am - 4:15 pm. We are located at 14001 Acme Road, Shawnee, OK. We are closed from 12 to 12:30 for lunch. You can use the drop box at the door anytime.
Frequently Asked Questions
How much does a Routine soil sample cost?
$10.00 for N-P-K analysis with pH and Buffer index, includes recommendations.
How often should a soil be tested?
A soil test should be conducted if fertilizer is going to be applied or when problems occur during the growing season. Once every year is recommended when nitrogen fertilizer is applied, and at least once every three years if P and K are concerned.
When is the best time to take soil samples?
Soil samples can be taken anytime throughout the year for checking pH, phosphorus and potassium status. Collect soil samples 1-2 months before planting. Early spring is a good time to take soil samples for summer crops, and summer is a good time to sample for fall and winter crops. This allows time for lime recommended to react with the soil and change the pH before the crop is planted. To assess soil available nitrogen, sample as close to planting as possible. For Lawns, the late spring (May) is a good time sample for warm season grass and the summer (mid-Aug) is good for cool-season grasses.
What tools and supplies are needed to take a soil sample?
A clean plastic bucket, a soil probe or a shovel are needed. Soil probes may be borrowed from our office, 24 hour check out and return.
How should a soil sample be taken?
Collect a core with a probe, or a slice with a shovel, of soil from the surface to 6 inches deep from 15 random locations across the sampling area. Mix the samples together in a clean plastic bucket. Fill a sandwich size zip top bag or 3 coffee cups worth and label it with name and location. ( ie. front yard, back yard, garden, north 40, joe’s place).
For most garden areas one sample/plot should be adequate. When you return the sample to the Extension Office specify the crop you wish to grow and the yield goal (fescue lawn, Bermuda lawn, garden)
For more information, visit the fact sheet leaflet: Soil Testing…the Right First Step.
Sometimes separated samples may be needed from a yard to reflect the different uses.
Can samples be taken when soils are wet?
Soil moisture does not affect the test results since samples are dried before they are analyzed. However, extremely wet soils are difficult to collect and mix. Therefore, allow soils to drain before sampling. Soils too dry are normally hard to get to the right depth.
Welcome to the Season of Vegetable Gardening!
- Vegetable Basics
For gardeners, it is a great opportunity to plan your vegetable gardens and plan to plant enough to share with your family and neighbors! Share your knowledge or learn something new.
It may be a year to bring back the Victory Garden. Learn about some really neat garden history for our country.
Look at your planting dates in the Oklahoma Garden Planning Guide OSU Fact Sheet
- Cool season gardens are in progress already
- Prepare beds and soil for April. (scroll down) Use some spaces where you may normally plant annual flowers for veggies. Note heights and space needed. Leafy greens, radish, beets, kale, and cabbage will stay low growing during the early season. Green beans will fit that space after mid-April, providing some bloom, and fresh green beans!
- Our frost-free date in central Oklahoma is April 15 for warm season veggies. Wait until it's time, chilled plants will be slow to take off and slow to produce. 'Harden off' plants on your porch, if purchasing early. The little packs do dry out quickly, but don’t over-water.
- Don't plant everything at once! Space your plantings in two week intervals to stagger the harvest. Great for Lettuce, spinach, radishes, herbs--like chives, cilantro. Consider just how many radishes can you eat in a week, as well as the shelf life of what you are planting.
- Utilize containers, if you have poor soils, limited space, or poor drainage. Select varieties for smaller spaces.
- Plant Bush tomatoes, Bush beans, Compact squash. Or go vertical with a trellis or tomato cage for peas or pole beans, train cucumbers to trellis, etc. Use the square foot gardening template for containers = spacing for seeds. Google search: square foot gardening chart.
- Full sun for best production.
Get outside and enjoy the springtime. Gardening has so many benefits! Exercise, sunshine, local food production, stress relief, and mental well-being.
- Establishing a New Vegetable Garden Site
From community gardens to homeowners to 4-H garden projects, consider these things when choosing a new place for a garden site:
- Sun exposure – select a site that receives at least 6 hours of direct sunlight each day. Southern exposures are ideal for greatest sun incidence.
- Soil – well-drained soils such as sandy loam provide ideal conditions for growing vegetables. Soil pH near 6.6 is optimal. Avoid steep slopes where erosion will be a problem.
- Air flow – avoid low-lying areas as these tend to collect cold air which slows germination and plant development in spring.
- Avoid placing a vegetable garden near walnut trees. Walnuts exude a substance called juglone from their roots which is allelopathic, meaning it can kill other plants. Tomatoes and other solanaceous plants are highly sensitive to juglone.
- Water – Plants will need water! Make sure the site is situated near a water supply.
Removing Vegetation – It is important to start with a clean slate when preparing a new garden bed. And this means removing existing vegetation and controlling weeds. Usually, this is a chore for the summer prior to planting. There are several methods available to kill off vegetation. The most common method is to apply an herbicide, but there are other non-chemical methods such as solarization and smothering.
Solarization is a simple technique that captures radiant heat energy from the sun and uses that heat to kill seedlings and weed seeds, as well as some soil-borne disease organisms. To smother weeds cover the soil with black plastic or several layers of newspaper. Carpet or boards have also been used for smothering.
Solarization can be combined with other control methods. For example, an herbicide may be used to make the initial kill, then solarize to control subsequent seedlings and kill seeds in the soil. Solarization can also be combined with the application of soil amendments and fertilizers. In fact, solarization can speed up decomposition of organic matter, releasing soluble nutrients into the soil.
Whatever method is used, it is ideal to control perennial weeds before establishing a new garden. It will be much easier to manage them before you have the area planted with vegetables.
Soil preparation – Once the vegetation is removed, till the soil to loosen it. This is a good time to add manure or other organic material. To preserve soil structure, avoid tilling when the soil is too wet. To determine if the soil is too moist for tilling, grab a handful of soil and squeeze it slightly. If it sticks together in a ball it is too wet. If it crumbles easily it is ready.
How to Collect Soil for Testing – Soil tests should be included as part of garden preparation. It is easier to amend soils and add nutrients before planting, rather than after. Soil tests collect information on soil nutrients and pH. Extension Leaflet L-249 contains detailed information on collecting soil samples.
- Choosing Vegetables to Plant
Grow what your family will eat!
OSU Fact Sheet – HLA-6032 Vegetable Varieties and All-American Selections are great resources!
Look for disease resistant varieties.
- Heirloom seeds– These varieties are open pollinated, meaning you can save seeds for next season use.
- Hybrid seeds– Don’t save seeds, they may not be true to type. Many are improved and great choices for one season use.
- Organic seeds - Available at a higher cost (a personal choice) The production is about the same.
Use proven varieties and try something new annually; test out something you haven’t tried.
Plant in stages for fresh use, then it isn’t all ready at once. If you plan to can or freeze, time for harvest when you will be able to harvest and can or freeze. Our green beans always seemed to be ready to can during Vacation Bible School, no matter how much we planned! Note that if you usually travel in the summer, you don’t want to be gone during that peak production time either.
- Direct Seeding or Transplants?
As you plan your garden, think about what starts easily from seed and how much space they need.
Direct sowing is the least expensive method for: Green Beans, Pole Beans, Corn, Summer Squash, Okra, Cucumber, Cantaloupe, Watermelon, and Pumpkin, as well as many annual herbs. These are simply planted in the garden from seed into prepared soil. Planting depth and spacing are important. This information is on the back of the seed packet and in the Oklahoma Garden Planning Guide OSU Fact Sheet HLA-6004.
Transplants may be preferred for tomatoes, peppers, eggplant and perennial herbs. Mulching around the plants and in paths will help retain moisture and reduce weeds. Mulching a week or two after planting is ideal, then the sun will help warm the soil for a good fast start.
Then Water (when needed), Weed and Watch them grow!