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Located in the northeastern part of Oklahoma, Tulsa County is bordered on the west by Osage and Creek Counties; on the north by Pawnee, Osage and Washington Counties; on the east by Rogers and Wagoner Counties; and on the south by Wagoner and Okmulgee Counties. Tulsa, the county seat, is located in the central part of the county and is approximately 588 square miles or 376,320 acres. There are approximately 950 farms with an average size of 150 acres each. Major agriculture production areas are beef cattle, horses, hay (alfalfa and grass), wheat and soybeans.


The purpose of the Agriculture Extension Educator for Tulsa County is to assist people who are actively involved in agriculture production or those who are considering starting an agriculture enterprise. On-site consultations are provided free of charge to individuals pursuing production agriculture. To make an appointment with us, you may call us at (918) 746-3725. You can leave a voice message 24 hours a day, seven days a week and we'll return your call as soon as possible. 


OSU Extension develops programs based on science-based, objective information to help Oklahomans solve problems, promote leadership and manage resources wisely. Listed below are research topics:

Agriculture - Soil Test Instructions

Soil samples can be submitted to the Tulsa County OSU Extension Center, 4116 E. 15th St., (on 15th, between Harvard and Yale) or call (918) 746-3707 for more information. Each county extension office offers this service and works in conjunction with the OSU Soil, Water and Forage Analytical Laboratory to get your samples processed. Soil samples generally takes two or three weeks for results to become available. Payments are accepted in cash or check only. Checks can be made out to OSU.


Soil tests provide a scientific basis for evaluating available plant nutrients in cropland, pastures, lawns and gardens. Analyses of soil sample can help farmers and homeowners fine-tune nutrient applications from fertilizers, bio solids, and animal manure. Properly managing the amount of nutrients added to the soil can save money and protect the environment.


The steps for obtaining the sample are as follows:


  1. Using a trowel, shovel or soil probe, obtain six inch samples of soil, removing all grass and trash.
  2. Each area of interest, such as lawn, vegetable garden, pasture or field should be tested separately. It is recommended to test samples at the same time each year to maintain consistency in viewing your nutrient changes from year to year.
  3. Obtain fifteen to twenty random samples from the area you want tested. Divide the area and follow a random pattern when sampling. Avoid unusual spots, like a wet area, and try to obtain a representative sample.
  4. Place the random samples in a clean plastic bucket, mix thoroughly by hand, place at least a full pint of the random sample in a clean container or bag, label it, e.g., FRONT, BACK, SIDE of the house. Samples should not be saturated, but fairly dry. For most garden areas one sample/plot should be adequate.
  5. When you return the sample to the Extension Office specify the crop you wish to grow and the yield goal (lawn, garden and legume crops do not need yield goal).
  6. Submit your samples to the Tulsa County OSU Extension Office.


SWAFL Testing Fees & Other Tests

  • Basic Soil Test (pH, N, P & K) $10
  • Basic Feed/Forage Test (Protein, Moisture, ADF, TDN & Net energy: gain, lactation & maintenance) $24
  • Forage/Feed Nitrate Toxicity $6
  • Water (Irrigation, Household (Excluding Bacterial Test which is performed at most County Health Departments) & Livestock) $15 (Homebrewer) $18   
  • Animal Waste & Compost $25

For further information on these test or other test offered, please visit the Laboratory Services and Price List.


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.

( pH (1:1), Lime requirement (Sikora Buffer), NO3-N, Soil test P & K by Mehlich 3 (MIII))


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.


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. Put 2 cups of the mix into a soil sample bag or a clean container and label it. ( e.g., FRONT, BACK, SIDE of the house.)


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 (lawn, garden, and legume crops do not need yield goal). 


For more information, visit the fact sheet: PSS-2207 How to Get a Good Soil Sample.

Several 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.


Plant Disease Diagnostics

Through the OSU Extension office we can access OSU's Plant Disease Diagnostic Lab as well as discuss problems with experts in the entomology department. Samples are scanned and sent, via e-mail, to the OSU Stillwater campus for a quick, visual analysis and online consulting. If needed, we can then mail in actual samples for further diagnostic analysis. Also available is a digital diagostics database to view information on insects/arthropods and plant diseases.

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