Delaware Soil Testing Program
General Information on Routine Soil Testing and Sample Submission
We offer several types of tests to meet the needs of our varied clientele. The “Soil Fertility Tests” and the “Lead Screening Test” are the tests most commonly used by farmers, homeowners, landscapers and others who:
- want to know the fertility of their soil for the purpose of growing plants,
- are having difficulty growing plants and want to determine pH or fertility problems are the cause, or
- are concerned about the possible contamination of their yard or garden soil with lead.
A summary of these tests is shown here:
(fees effective 8/12/24)
Test |
Description | Fee |
Routine Soil Test with Lead for Home Gardeners |
pH, lime requirement, organic matter, Mehlich 3 extractable nutrients [Phosphorus (P), Potassium (K), Calcium(Ca), Magnesium (Mg), Manganese (Mn), Zinc (Zn), Copper (Cu), Iron (Fe), Boron (B), Sulfur (S) and Aluminum (Al)] and recommendations for three plants / crops. Includes screening for soil Lead content. | $22.50 |
Routine Soil Test for Agricultural Operations, Lawn Care Companies and Landscapers |
pH, lime requirement, organic matter, Mehlich 3 extractable nutrients [Phosphorus (P), Potassium (K), Calcium(Ca), Magnesium (Mg), Manganese (Mn), Zinc (Zn), Copper (Cu), Iron (Fe), Boron (B), Sulfur (S) and Aluminum (Al)] and recommendations for three plants / crops. | $18.00 |
Soluble Salts |
Measures dissolved salts, high levels of which may inhibit seed germination and be harmful to seedlings and sensitive plants. | $10.00 |
Pre-sidedress Soil Nitrate Test for Corn |
Measures soil nitrate levels in the soil at the point of maximum nitrogen uptake. Includes N recommendations and 24 hour turn around. | $18.00 |
Soil Lead Screening |
An initial screen for those who suspect that their soil may be contaminated with lead. The test requires a special soil test kit with specific instructions on collecting the sample. This test is only a screen and further testing by an environmental laboratory may be recommended based upon the results. | $20.00 |
Upon request, soil samples can be tested for heavy metals (in addition to the Soil Lead Screening test listed above): Arsenic (As), Cadmium (Cd), Chromium (Cr), and Nickel (Ni). Also upon request, soil samples can be tested for Sodium (Na). Contact the program at 302-831-1392 or email: Soiltest@udel.edu for additional information on requests for testing for the presence of heavy metals or sodium.
To have your soil tested, purchase the appropriate University of Delaware soil test kit at one of the locations listed below. (Refer to the section below: Where can I get a soil test kit?). The kit consists of an envelope with cloth bag attached and an information sheet appropriate to the type of testing you require (e.g., commercial farm, lawn&garden, soil lead screening, PSNT). Following the directions given in the “How to Collect a Soil Sample” brochure, use a clean bucket and trowel, spade or soil probe to collect a representative sample of the site. Thoroughly mix the soil. Place 1 to 1½ cups of mixed soil into the plastic bag and place the plastic bag into the cloth bag. Tie the end closed with the drawstring. Fill out the information sheet and enclose it in the envelope. The completed sample can then be returned to the Soil Testing Program.
Introduction to Soil Testing
Soil tests conducted by the University of Delaware help you develop and maintain more productive soil. By providing information about your soil's fertility status, these tests allow you to select the proper liming and fertilization programs to maximize economic yields.
Because a small, half-pound sample is used to represent millions of pounds of field soil, it is extremely important that samples are taken properly and carefully.
When and How Often to Test
Annual Crops: Testing annually is generally recommended. If fertility levels are very high, sampling every 2 to 3 years is adequate.
Perennial Crops (e.g., Alfalfa/Pasture): Test prior to seeding and at least every 3 years thereafter.
Lime Requirements: If lime is needed, sample well in advance of planting, as it takes several months to react with the soil.
Selecting the Sampling Area
A good soil sample should represent only one soil type or condition.
Sampling Guidelines:
Maximum Size: In general, 40 acres is the maximum area that should be represented by a single sample.
Separate Samples: Areas with different soil types (e.g., Sandy Knoll vs. Black Soil) or different management histories (e.g., Corn field vs. Soybean field) must be sampled separately.
Avoid Unusual Areas: Stay away from wet spots, dead furrows, or areas where manure, lime, or fertilizer was stockpiled. Do not take cores from identifiable previous fertilizer bands.
Proper Sampling Techniques
1. Depth
Standard Depth: Soil samples are generally taken to the plow depth, usually 6 to 9 inches from the surface.
No-till/Reduced-tillage: These should also be sampled to the 6 to 9-inch depth for fertilizer recommendations.
Herbicide Assessment: Surface 2-inch samples are used specifically to assess herbicide activity problems.
2. Tools and Cleanliness
Prevent Contamination: Use clean tools and containers. Even small amounts of fertilizer or lime residue on your hands or tools can contaminate the sample.
Materials: Steel sampling tools and plastic buckets are best.
Avoid: Do not use galvanized, brass, or bronze tools if testing for micronutrients like copper and zinc.
3. Collection Process
Composite Sampling: Each individual sample should consist of 15 to 25 "cores" taken from throughout the sampling area.
Mixing: Collect all cores in a clean bucket and mix them thoroughly.
Packaging: Fill the official soil sample bag provided by the laboratory to the indicated line.
Forwarding the Sample
Record Keeping: Number each sample and keep a record of which field area it represents.
Documentation: Fill out the information sheet provided with the bag completely for better fertilizer recommendations. Place the sheet in the attached envelope.
Payment: Purchasing a sample bag automatically pays for routine analysis. Special tests must be paid for in advance at the county extension office.
Submission: Samples can be dropped off at your county extension office or mailed to:
Why Test Your Soil?
Soil tests conducted by the University of Delaware Soil Testing Laboratory help you develop and maintain more productive soil. By providing information about the fertility status of your soil, these tests help you select the proper liming and fertilization programs to obtain optimal growth for your lawn, garden, and ornamental plants.
A soil test is only as accurate as the sample on which it is made. A soil sample weighing about 1/2 pound is used to represent thousands of pounds of soil in a lawn or garden. Therefore, it is extremely important that soil samples be taken properly and carefully.
How Often Should Soil Be Tested?
Lawn and Ornamental Areas: Once adequate fertility levels are established, these areas only need to be sampled every 2 to 3 years.
Vegetable Gardens: These should be sampled every 1 to 2 years.
Planning for Lime: If lime is likely to be needed, be sure to sample well in advance of planting. Because lime reacts fairly slowly, it should be mixed with soil several months before planting.
Defining the Sampling Area
Each soil sample should represent only one soil type or soil condition.
Sample Separately: Areas where past treatment has been different should be sampled separately. For example, take individual samples for a garden, a lawn, and a shrub planting.
Lawn Variations: If front and back lawns have been treated differently, take a separate sample from each.
Identify Problem Areas: Areas where plants grow differently or the soil appears different should be sampled separately.
How to Take a Good Soil Sample
A good soil sample must represent the entire area being tested.
1. Collect Cores or Slices
General Areas: Take soil from at least 10 locations (marked as "X" throughout the area) and mix them together in a clean bucket.
Trees and Shrubs: Take soil from 5 to 6 spots around the base of the plant and mix.
Tools: Use a trowel, spade, or sampling tube. If using a trowel or spade, vertically cut a slice of soil about 2 inches thick to the correct depth.
2. Sample to the Proper Depth
Before sampling, remove any surface litter such as turf thatch or mulch.
Lawns: Sample down to 4–5 inches.
Gardens and Ornamentals: Sample down to 6–8 inches.
3. Do Not Contaminate the Sample
Use Clean Tools: Always use clean sampling tools and containers.
Avoid Residue: NEVER use tools or containers that have previously held fertilizer or lime. A small amount of residue on tools or hands can cause serious contamination of the sample.
Mixing and Packaging
Mix Thoroughly: Collect all cores or slices for a given sample in a clean bucket and mix them thoroughly.
Fill the Bag: Fill the official soil sample bag to the indicated line with the mixed soil.
Use Official Bags: Do not use sample bags other than those provided by the laboratory.
Forwarding the Sample
Labeling: Name each sample and keep a complete record of the area it represents.
Information Sheet: Fill out the information sheet provided with each sample bag and place it in the attached envelope.
Submission: Samples may be dropped off at your county Extension office or mailed directly to:
Soil Testing Program
152 Townsend Hall, CANR
University of Delaware
Newark, DE 19716-2170
Payment: Purchasing a sample bag automatically pays for routine analysis. Special tests must be paid for in advance at the county Extension office; include the receipt with your sample.
Option A: (On-Line)
Soil test kits may be purchased on-line from this web site by going to the Order Kits tab.
Or;
Option B: (County Extension Office)
Soil test kits can be obtained at any of the three UD Cooperative Extension Offices listed below. Payment will be made directly to the Soil Testing Program by enclosing payment with the kit or by checking the box that you wish to pay be credit card and providing a daytime phone number where you can be reached. Program staff will then contact you for payment information.
New Castle County |
Kent County |
Sussex County |
501 S. College Ave. |
Paradee Center |
Research and Education Center |
Or; Option C: (On-site or via mail)Soil test kits may also be purchased on-site or ordered directly from the UD Soil Testing Program. To order by mail, send a letter indicating the number and type of kits requested along with check for the appropriate amount payable to “University of Delaware”. Be sure to indicate the address to which the kits should be mailed. Send the request to: UD Soil Testing Program |
|
Option D: Mailer kits may also be available from local garden centers. You can call our office (302-831-1392) to see which locations near you may have kits on-hand. |
How to Submit Samples Without Regular Soil Test Bags
If you want to submit a sample and do not have a kit, please follow the steps listed below:
1. Collect a representative sample by following the directions from the drop-down menu below.
2. Thoroughly mix each sample and place 1-1.5 cups of the mixed sample into a ziplock bag. Label the bag with your name and the sample ID (e.g., Field 6, Backyard, etc)
3. Down the appropriate information sheet from the “Soil Testing Program Forms” page at right. Complete one copy of the information sheet for each sample. Be sure that the sample ID on the bag and the sample ID on the information sheet match.
4. Enclose payment or indicate on the back of the information that you wish to pay by credit card. Checks should be made payable to the University of Delaware. If paying by credit card, DO NOT write your card number on the information sheet. Instead, list a daytime phone number and our office will contact you for payment.
5. Place the samples and information sheet in a box or mailing envelope and send to the laboratory using the following address above.
Mailer kits may also be available from local garden centers. You can call our office to see which locations near you may have kits on-hand.
Additional Questions Please call the office at 302-831-1392 or email Soiltest@udel.edu with any additional questions you may have. We are in the office and happy to help.
Introduction to Soil Testing
Soil tests conducted by the University of Delaware help you develop and maintain more productive soil. By providing information about your soil's fertility status, these tests allow you to select the proper liming and fertilization programs to maximize economic yields.
Because a small, half-pound sample is used to represent millions of pounds of field soil, it is extremely important that samples are taken properly and carefully.
When and How Often to Test
Annual Crops: Testing annually is generally recommended. If fertility levels are very high, sampling every 2 to 3 years is adequate.
Perennial Crops (e.g., Alfalfa/Pasture): Test prior to seeding and at least every 3 years thereafter.
Lime Requirements: If lime is needed, sample well in advance of planting, as it takes several months to react with the soil.
Selecting the Sampling Area
A good soil sample should represent only one soil type or condition.
Sampling Guidelines:
Maximum Size: In general, 40 acres is the maximum area that should be represented by a single sample.
Separate Samples: Areas with different soil types (e.g., Sandy Knoll vs. Black Soil) or different management histories (e.g., Corn field vs. Soybean field) must be sampled separately.
Avoid Unusual Areas: Stay away from wet spots, dead furrows, or areas where manure, lime, or fertilizer was stockpiled. Do not take cores from identifiable previous fertilizer bands.
Proper Sampling Techniques
1. Depth
Standard Depth: Soil samples are generally taken to the plow depth, usually 6 to 9 inches from the surface.
No-till/Reduced-tillage: These should also be sampled to the 6 to 9-inch depth for fertilizer recommendations.
Herbicide Assessment: Surface 2-inch samples are used specifically to assess herbicide activity problems.
2. Tools and Cleanliness
Prevent Contamination: Use clean tools and containers. Even small amounts of fertilizer or lime residue on your hands or tools can contaminate the sample.
Materials: Steel sampling tools and plastic buckets are best.
Avoid: Do not use galvanized, brass, or bronze tools if testing for micronutrients like copper and zinc.
3. Collection Process
Composite Sampling: Each individual sample should consist of 15 to 25 "cores" taken from throughout the sampling area.
Mixing: Collect all cores in a clean bucket and mix them thoroughly.
Packaging: Fill the official soil sample bag provided by the laboratory to the indicated line.
Forwarding the Sample
Record Keeping: Number each sample and keep a record of which field area it represents.
Documentation: Fill out the information sheet provided with the bag completely for better fertilizer recommendations. Place the sheet in the attached envelope.
Payment: Purchasing a sample bag automatically pays for routine analysis. Special tests must be paid for in advance at the county extension office.
Submission: Samples can be dropped off at your county extension office or mailed to:
Why Test Your Soil?
Soil tests conducted by the University of Delaware Soil Testing Laboratory help you develop and maintain more productive soil. By providing information about the fertility status of your soil, these tests help you select the proper liming and fertilization programs to obtain optimal growth for your lawn, garden, and ornamental plants.
A soil test is only as accurate as the sample on which it is made. A soil sample weighing about 1/2 pound is used to represent thousands of pounds of soil in a lawn or garden. Therefore, it is extremely important that soil samples be taken properly and carefully.
How Often Should Soil Be Tested?
Lawn and Ornamental Areas: Once adequate fertility levels are established, these areas only need to be sampled every 2 to 3 years.
Vegetable Gardens: These should be sampled every 1 to 2 years.
Planning for Lime: If lime is likely to be needed, be sure to sample well in advance of planting. Because lime reacts fairly slowly, it should be mixed with soil several months before planting.
Defining the Sampling Area
Each soil sample should represent only one soil type or soil condition.
Sample Separately: Areas where past treatment has been different should be sampled separately. For example, take individual samples for a garden, a lawn, and a shrub planting.
Lawn Variations: If front and back lawns have been treated differently, take a separate sample from each.
Identify Problem Areas: Areas where plants grow differently or the soil appears different should be sampled separately.
How to Take a Good Soil Sample
A good soil sample must represent the entire area being tested.
1. Collect Cores or Slices
General Areas: Take soil from at least 10 locations (marked as "X" throughout the area) and mix them together in a clean bucket.
Trees and Shrubs: Take soil from 5 to 6 spots around the base of the plant and mix.
Tools: Use a trowel, spade, or sampling tube. If using a trowel or spade, vertically cut a slice of soil about 2 inches thick to the correct depth.
2. Sample to the Proper Depth
Before sampling, remove any surface litter such as turf thatch or mulch.
Lawns: Sample down to 4–5 inches.
Gardens and Ornamentals: Sample down to 6–8 inches.
3. Do Not Contaminate the Sample
Use Clean Tools: Always use clean sampling tools and containers.
Avoid Residue: NEVER use tools or containers that have previously held fertilizer or lime. A small amount of residue on tools or hands can cause serious contamination of the sample.
Mixing and Packaging
Mix Thoroughly: Collect all cores or slices for a given sample in a clean bucket and mix them thoroughly.
Fill the Bag: Fill the official soil sample bag to the indicated line with the mixed soil.
Use Official Bags: Do not use sample bags other than those provided by the laboratory.
Forwarding the Sample
Labeling: Name each sample and keep a complete record of the area it represents.
Information Sheet: Fill out the information sheet provided with each sample bag and place it in the attached envelope.
Submission: Samples may be dropped off at your county Extension office or mailed directly to:
Soil Testing Program
152 Townsend Hall, CANR
University of Delaware
Newark, DE 19716-2170
Payment: Purchasing a sample bag automatically pays for routine analysis. Special tests must be paid for in advance at the county Extension office; include the receipt with your sample.
Typically, your results will be mailed out within 10 working days (M-F) of the sample’s arrival at the laboratory. During peak periods (December – Early April), it may be as long as 15 working days.
Should you have questions about your soil test results and / or recommendations can be answered by either your local county Extension agent or by the Master Gardener Garden Help Line. The phone numbers for Delaware Cooperative offices are listed above and are also printed on the soil test report for all Delaware residents. Clients from other states can find the phone numbers for their local Cooperative Extension office in their local phone book.
Soil test results are stored in our archive for several years. If you wish to have new reports generated, please call the Soil Testing Program Office at (302) 831-1392. Give us your name, bag number and/or lab number and we will be happy to generate a new report for you.
Routine fertility test reports are printed on UD Soil Test Report Forms. Reports for other sample types are usually generated in spreadsheet format. Hardcopies of reports will be mailed to the client and any other designated party specified on the sample information sheet or the analysis request form.
Copies of routine fertility soil test reports for Delaware clients will be sent to their County Extension Office so that Cooperative Extension Staff my assist clients with questions about their reports. Individual report information will not be released to any persons other than those whose names are listed on the report except by the written request of the paying client(s) to the Director of the University of Delaware Soil Testing Program.
Electronic copies of reports, either as pdf files, a spreadsheet or NuManPro data file, may be requested in addition to the hard copy version. Please provide your e-mail address on your information sheet or analysis request form to be sent an electronic copy.
Can't find what you are looking for?
Contact Karen Gartley at kgartley@udel.edu
Location
531 S College Ave, Newark, DE 19716-2170.
Phone: 302-831-1392
Fax: 302-831-0605
More information