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Frequently Asked Questions


What soil tests are available?

Tests offered at the IFAS Extension Soil Testing Laboratory and fee schedule can be found here: http://soilslab.ifas.ufl.edu/ESTL%20Tests.asp

Why test my soil?

Florida has plenty of sunshine and rainfall, but its soils are often lacking in nutrients and other attributes necessary for good plant growth. To improve your soil’s productivity, you should know each of the following soil attributes:

  • pH
  • Lime requirement
  • Major nutrient levels (P,K, Ca, Mg)
  • Micronutrient levels (Cu, Mn, Zn)
  • Irrigation water quality

If you don’t have this information, a soil test may help. The UF/IFAS Extension Soil Testing Laboratory (ESTL) conducts tests on soil samples year-round. ESTL offers soil tests for home and commercial growers.


How do I take a soil sample?

  1. 1. Before sampling, develop a soil sampling plan for your field or yard. Samples should best represent the area being tested, so collect samples from the areas that are of the same soil type, appearance, or cropping history. Problem areas or areas that are different should be sampled and submitted separately. From this plan, count the number of samples you will collect. About 1-2 representative samples from each area of the home yard or landscape and 1-5 samples from 20-40 acres of commercial farms should be collected and sent for analysis.
  2. 2. Contact your local county UF/IFAS Extension office for soil sample bags, shipping boxes, and sample submission forms free of charge, as well as advice about sampling. Forms are also available on our website. Assemble all the materials you need to complete sampling according to your plan.
  3. 3. Collect soil from 20 or more spots within each area, mixing these samples in a clean plastic bucket.
  4. 4.Sample from soil surface to depth of tillage, usually 0 to 6 inches.
  5. 5.Spread the composited material on clean paper or other suitable material to air dry. Do not send wet samples.
  6. 6.Mix the dry soil, and place about one pint of soil in a labeled sample bag or to the dotted line on our sampling bag.

How do I send samples to the lab?

  1. 1. Enter each sample’s identification on its sample bag or bottle and in the “Sample Identification” column. List each sample separately.
  2. 2. Include the Test Code for each desired test or circle the cost of the test. Enter costs for the analysis in the cost column.
  3. 3. Crop Codes are required to get lime and fertilizer recommendations. Crop Codes can be found on the back of the forms.
  4. 4. Sum the costs of all samples and analyses. Make check or money order payable to: University of Florida. Checks written in any other name(s) will NOT be honored, will be returned and will cause an avoidable delay in processing the samples.
  5. 5. Include the completed Test Information Sheet and the check or money order in the shipping box with the sample(s).

How long before I get the results back?

Typically, a test report will be emailed/mailed to you within 2 working days after your sample arrives at the Extension Soil Testing Laboratory. Contact your county Extension agent at the number and address listed on your report with any questions about the report and its recommendations. More information about plant nutrient problems may be obtained with a plant tissue test and/or a water test.

What other tests can I get?

ESTL offers testing for irrigation water samples, plant tissue and livestock waste.
Irrigation Water Test: Hardness and fine sediments can clog the nozzles of irrigation systems and high salt content can adversely affect the soil pH and plant health. This is particularly important to those depending on wells for irrigation and those using reclaimed water for landscape irrigation. Reclaimed water may at times contain some plant essential minerals.
Plant Tissue Test: Determining nutrient concentration in plant tissue samples can be important for perennial plants, crops and home lawns (all plant species that grow more than a season or a year). A plant tissue test is recommended especially when the leaves exhibit any deficiency symptoms or when growth is inhibited. In the case of perennial plant species a soil test alone may not provide the necessary insight on nutrient deficiencies. Certain physiological imbalances may occur, either inhibiting the uptake from soils or usage after uptake within the plants, despite application of nutrients to the soils as per the recommendations. Additional diagnosis and nutrient adjustments may help overcome the deficiencies and growth imbalances. The need for the water and/or plant tissue tests can be ascertained along with obtaining additional information on any of the tests by contacting your local extension agent or Master Gardener at your local UF/IFAS Extension Office.

Who should I make the check payable to?

All checks should be made payable to: “University of Florida”.

Do I need to have a soil test done?

Your local extension agent will be able to help you if a soil test is appropriate for your case.

Do I need to dry the samples?

Both soil and plant tissue samples should be air dried and placed into paper bags prior to shipping. Do NOT use plastic bags for leaf or other plant tissue samples.

Who is to send the samples?

The customer is responsible for sending the samples to the Lab. However, assistance may be sought from the local county office with submission forms, choosing a test or fees to be included.

Will the extension office be mailing the soil sample out for me?

A few county extension offices send the samples on your behalf. However, please check with your local county extension office to see if the facility is available.

What is being tested (pH/lime vs. fertilizer)?

Different test packages test for different parameters. Your local county extension office can help guide you to the test appropriate for your case. Please check here for different parameters tested for different tests.

My plants aren't doing well, should I do a soil test?

The reason may or may not be soil test related. Your local extension agent will be able to help you if a soil test is appropriate for your case.

What do the results mean?

The results of your soil test tell you the available nutrients in your soil sample and the test report will tell you how much, if any, of the nutrients that you will need to apply for your particular crop or grass species.

Will a soil test tell me what chemicals or diseases are in the soil?

No. The IFAS soil test lab does not test for diseases or other organic chemical contaminants in the soil.

Is there a test available for nitrogen (N) in the soil samples?

No. There is no test available for nitrogen in the soils. Such a test would be unreliable because of quick changes occur to chemical forms of nitrogen in the soil continuously and naturally.

If there is no soil test for nitrogen (N), then how are the recommendations made for N for my crop or grass species?

The N recommendations are derived from research data from studies conducted on N requirement of the crops/grasses. Therefore, a soil test is not required if you are only looking for N recommendations. Your local county extension agent or Master Gardener may be able to look up and provide you the N fertilizer amount recommended from the IFAS publications.

If I live in Miami-Dade or Monroe County, do I need a soil test done?

Yes. A soil test is always the most scientific way of assessing the soil nutrient status. However, in Miami-Dade or Monroe County because of extremely high amounts of lime rock in the soils, soil test interpretations are limited. The report may contain recommendations for potassium and magnesium, you may not receive any recommendation for phosphorus. Recommendations for nitrogen (N) will be included in the reports, although N recommendations are not derived from a soil test. Please consult with your local county extension agent for additional details.

How often should I be testing the soil in my yard?

A routine soil test should be done once every 2 years if the landscapes plants and lawns are managed and expected to perform optimally.

When should I expect to receive my results and can the agent help me with the interpretations?

If an email is provided, the results should be available in about 2 working days after the laboratory receives the soil. If the soil sample is wet when received at the Lab, it may take additional time for the results. Results are always emailed to the county extension office immediately. If no email address is provided, results will be sent via regular mail in 2 working days and may take longer to be received.

Can I use a plastic bag instead of a paper one for soils?

A plastic bag may be used only when the soil sample is dry. This will help prevent any growth of mold. However, paper bags are always preferred for both soils and plant or leaf tissue samples. Free soil sample bags are available at your local county extension offices.

Will a soil test determine if nematodes are a problem?

No. The IFAS soil test lab does not test for nematodes. The IFAS Nematology Assay Lab can test for nematodes.

How much (volume) soil do I need?

Approximately, a pint of air-dried soil sample is required by the Lab. Please fill up to the dotted line on the soil sample bag.

Can I hand-deliver my samples to the lab?

Yes, our laboratory is open from 8 AM to 12 noon and from 1 PM to 5 PM, Monday thru Friday, during a regular work week.

How do I package the sample?

The free priority mailing boxes from the US Post Office can be used to mail the samples to the Lab. Free soil sample bags are available at your local county extension offices.

How do I contact the lab if I have questions?

Our phone number and email address are on the soil sample submission form or an inquiry can be sent through our web site: http://soilslab.ifas.ufl.edu

More details can be found in our brochure.

My grass is not doing well or plants are dying. Should I have a soil test done?

The reason may or may not be soil test related. Your local extension agent will be able to help you if a soil test is appropriate for your case.

What is a soil extractant?

Soil extractant solution is a reagent with certain chemicals that gets added to the soil sample. The extractant solution mimics the root extraction of nutrients in the soils and pulls the nutrients from the soil sample into soil solution. Different extractants are used for different soils in Florida.

What is the extractant used by the IFAS lab?

The soil extractant used for acid-mineral soils in Florida is called Mehlich-3. Currently, for high pH or alkaline soils the extractant used is Ammonium Bicarbonate-DTPA (AB-DTPA).

How are the test results interpreted?

The following chart provides interpretation for ranges of soil test nutrients into Low, Medium and High categories for agronomic and horticultural crops grown on acid soil (soil pH lower than 7.3). The values are in ‘parts per million (ppm) using Mehlich-3 (M-3) extraction method’:

Nutrient Low Medium High
P ≤ 25 26-45 > 45
K ≤ 35 36-60 > 60
Mg ≤ 20 21-40 > 40

What is A-E Buffer Value printed on the reports?

A-E Buffer Value refers to Adams-Evans Buffer test value done to determine the amount of lime required for the particular soil to raise the pH to a specific level. This pH is different from the Soil pH value.

Can we determine lime requirement from the soil pH test value?

No. It will be erroneous to try and estimate or calculate the lime requirement using just the soil pH value. Lime requirement can be determined only using the Adams-Evans Buffer test value in conjunction with the soil pH value. So, soil pH alone should NOT be used to determine or predict the amount of lime required to raise the pH.

My pool water is discharged into my yard. Should I do a soil test to see why my grass is dying?

They may not be related so your local extension agent may be able to help you if a soil test is appropriate for your case.

For pasture grasses such as bahia, should I choose the Low, Medium or High nitrogen option?

Unless the grass pasture is managed intensively, hayed or is commercially and economically viable and/or is irrigated, High N option is not recommended. For grazing purposes, typically Low N option is appropriate. If the grass performance is poor and needs improvement, Medium N option can be considered in the season and when expecting seasonal short rainfall.

The different nitrogen options for the bahia test are explained in UF/IFAS publication SL-129, UF/IFAS Standardized Fertilization Recommendations for Agronomic Crops.

I can't find bag with a specific nutrient ratio- for example- 2-1-2 or 0.25-0- 0.35, etc. Should I look for this ratio when purchasing fertilizer?

Fertilizer recommendations are provided for individual nutrients and therefore cannot be always found in ratios that are commercially available. Either you will need to find straight fertilizers that provide single or individual nutrient or a ratio that is closest to the recommended amounts. Caution should be applied to avoid excess amounts of nitrogen or phosphorus nutrients at all the times. Your local county extension office can provide more information of finding the right choices and on minimizing any environmental negative impacts.

Why is the soil pH so much different that when I had it tested in years past? It was usually 6.5-7.0 and now it is 5.0.

Multiple soil, management, application of different fertilizers and/or soil amendments, irrigation and weather factors can dynamically affect the soil pH. In the southeastern region of the US, if some of the basic nutrients such as calcium, magnesium, potassium are not applied regularly to soils producing crops or aesthetic landscapes, soil pH may drop down to acidic ranges you mentioned.

Are there any other Labs that can provide testing for parameters such as pesticides, chemical contaminants/heavy metals, etc.?

Yes. There are several other commercial laboratories that may provide other tests and services that the IFAS Labs cannot provide. A quick search on the internet can provide the contact information. Also, a list of labs is available on Florida Department of Environmental Protection web site for certified laboratories: https://fldeploc.dep.state.fl.us/aams/analyte_search.asp

Why can’t plant diseases or nematodes be tested at the IFAS soils lab?

The IFAS Soils Lab provides nutrient analyses in soil, plant tissue, water and manure/composts/other organic waste samples. Samples for plant diseases testing should be sent to the IFAS Plant Diagnostic Center or for nematode testing to the IFAS Nematode Assay Lab in Gainesville.