Soil Sampling, Submissions, Pricing
The Soil, Water and Plant Testing Laboratory offers analytical testing and science-based recommendations to help clients make informed resource management decisions. Services include comprehensive testing of soil, water, plant tissue, manure, compost, and other agricultural materials. These fee-based services are available to homeowners, agricultural producers, landscape professionals, consultants, government agencies, and University faculty and staff.
Sampling Instructions
Understanding your soil is the cornerstone of successful gardening, landscaping, and agriculture. Soil testing provides crucial insights into nutrients and mineral levels, pH balance, organic matter, and other chemical, physical, and biological soil characteristics for plant growth. However, the reliability of the soil test results depends upon the quality of the sample submitted. The soil test result is only as good as the sample collected. A sample must reflect the average soil properties across the area of interest (a field, garden, lawn, or flower bed).
Read Soil Sampling Instructions
Tools
- A stainless steel soil-sampling probe, an auger, or a shovel/trowel (Figure 1)
- Clean bucket
- Plastic bags or waterproof lined paper bags
- Permanent marker
Sample Collection
Use a systematic and/or random sampling pattern to collect samples (Figure 2). The number of samples you need to collect depends on the size and variability of the sampling area. In general, more samples are better as they provide a more accurate representation.
Collect a representative composite sample by combining 10 to 15 samples from the soil surface (0 inches) to a depth of 6
inches OR 8 inches (0-6” or 0-8”) for vegetable garden and flower beds; from the soil surface to 2 inches OR 3 inches. (0-
2” or 0-3”) for lawns; and from the soil surface to 8 inches (0-8”) for agricultural crops.
Submit a separate sample for areas with different crop growth, soil color, or fertilizer/amendment history. For example, a homeowner may submit one sample from a vegetable garden, one from a flower bed, and one from a front lawn. A farmer may submit a sample from each field, different crops, or from an area of low and/or high productivity.
When using a soil probe, Insert it into the soil to the proper depth (0-6” or 0-8”). Remove the soil core and place it into a clean bucket. Repeat this process at each of the predetermined subsampling points within your designated area.
If a tool such as a spade is used, dig a V-shaped hole to sample depth (6 inches OR 8 inches); then cut a thin (approximately 1 inch thick) slice of soil from one side of the hole. For the sample, save a 1-inchwide strip of soil from the center of the spade (Figure 3).
When using an auger for sampling, bore a hole to the desired sampling depth (6 inches OR 8 inches) and then withdraw it. Replace the auger tip with a core sampler, lower it down the borehole to the sampling depth. Withdraw the tube core sampler and collected the sample.
Once you have collected all the necessary subsamples from your defined area, it is time to combine them into one representative sample. This is referred to as a composite sample.
Thoroughly mix all the subsamples in a clean bucket. This ensures that any variations between sampling points are averaged, giving a more accurate representation of the soil conditions. Break up any large clumps of soil, remove and discard surface litter (crop residue, grass, wood chips, manure, roots, or rocks/gravel), and mix thoroughly until you have a homogeneous mixture.
Take one pound of the mixed soil from the bucket and place it in a clean plastic bag or waterproof lined paper bag. This is the representative composite sample to be submitted to the Lab.
Using a permanent marker, label the bag with your name, sample depth, and sample name such as FIELD1, GARDEN1, LAWN, BACK YARD, etc. Fill out the appropriate submittal form, found on this web page. For lawns, vegetable gardens, flower beds, trees, and orchards as well as reclamation sites, use the Horticulture Soil Submission Form. For agricultural crops, use the Crop Soil Submission Form. Make sure that the sample name on the bag matches the Sample ID on the submission form.
Selecting a Soil Test
The soil testing packages offered by the SWPTL are soil management tools for anyone interested in diagnosing and correcting soil fertility problems, determining the fertilizer requirements of their crops and improving soil health.
Our most popular soil test is S1. This comprehensive test is suitable for farmers and ranchers, agronomists, homeowners, landscape professionals, and environmental consultants. It provides information on all essential nutrients and minerals a crop/plant needs for optimum growth and development.
Soil Texture (S11) is also a key test to understand soil water and nutrients holding capacity and water drainage, and organic matter decomposition among other soil properties. This test determined the percentage of sand, silt and clay.
Submitting Samples
Colorado State University County Extension offices throughout the state provide sample bags, tools and technical assistance for collecting and shipping samples, and results interpretation.
Samples can be submitted in person or mailed. When mailing samples, place sample(s) and submittal form in a sturdy box or envelope. Seal the box with packing tape and mail it to the address on the submittal form. You will receive the soil testing report within 7 to 10 business days.
Dropping or Mailing Address:
Soil Water and Plant Testing Lab
Terra Building T 3-16
4780 National Western Drive
Denver, CO 80216
Payment
Payment is expected at the time of sample(s) submission. Purchase orders are accepted for city offices, landscape companies, crop and environmental consultants, schools and universities.
With the exception of existing accounts, all other sample submissions must be accompanied by a check or money order made payable to Colorado State University for the total amount due.
For information about purchase orders, invoicing or payment, contact the SWPTL at soiltestinglab@colostate.edu or by phone at (970)491-5061.
Soil Analysis Price List
| Test Code | Price per sample | Description | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S1 | $47.50 | Complete: pH, Soluble Salts (EC), Organic Matter (OM), Lime, Cation Exchange Capacity (CEC), % Base Saturation, Nitrate-N (NO3), Phosphorous (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na), Sulfate-Sulfur (SO4-S), Zinc (Zn), Iron (Fe), Manganese (Mn), and Copper (Cu) | ||||||||||
| S2 | $40.00 | Basic: pH, Soluble Salts (EC), Organic Matter (OM), Nitrate-N (NO3), Phosphorous (P), Potassium (K), and Sulfate-Sulfur (SO4-S) | ||||||||||
| S3 | $57.00 | Soil Salinity: pH, Soluble Salts (EC), Bicarbonate, Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na), Sulfate-Sulfur (SO4-S), Chlorite (Cl), and Sodium Adsorption Ratio (SAR) | ||||||||||
| S4 | $25.00 | pH and Soluble Salts (EC) | ||||||||||
| S5 | $25.00 | Nitrate-Nitrogen (NO3-N) or Ammonium (NH4-N) | ||||||||||
| S6 | $25.00 | Subsoil Nitrate-Nitrogen (NO3-N) or Sulfate-Sulfur (SO4-S) | ||||||||||
| S7 | $25.00 | Boron (B) | ||||||||||
| S8 | $25.00 | Chloride (Cl-) | ||||||||||
| S9 | $210.00 | Heavy Metals: Arsenic (As), Cadmium (Cd), Chromium (Cr), Lead (Pb), Molybdenum (Mo), and Selenium (Se) | ||||||||||
| S10 | $45.00 | Individual Heavy Metal per sample plus extraction | ||||||||||
| S11 | $32.00 | Soil Texture by Hydrometer: Sand, Clay, Silt, Texture Class | ||||||||||
| S12 | $25.00 | Sodium Adsorption Ratio (SAR) | ||||||||||
| S13 | $25.00 | Soil Organic Matter (SOM) by Loss on Ignition (LOI) | ||||||||||
| S14 | $25.00 | Total Carbon (TC), Total Nitrogen (TN) and Carbon (C)/Nitrogen (N) Ratio (C:N) | ||||||||||
| S15 | $27.50 | Total Carbon (TC), Total Organic Carbon (TOC) and Total Inorganic Carbon (TIC) | ||||||||||
| S16 | $45.00 | Soil Minerals Zinc (Zn), Iron (Fe), Manganese (Mn), Copper (Cu) and boron (B) | ||||||||||
| S17 | $40.00 | Soil Respiration (24 h incubation) | ||||||||||
| S18 | $40.00 | Permanganate Oxidizable Carbon (POX-C) | ||||||||||
| S19 | $40.00 | Potential Mineralizable Nitrogen (28 day-incubation) | ||||||||||
| S20 | $45.00 | Wet Aggregate Stability | ||||||||||
| S21 | $45.00 | Field Capacity, Wilting Point and Plant Available Water | ||||||||||
| S22 | $45.00 | Cation Exchange Capacity (CEC), Calcium (Ca), Magnesium (Mg), Potassium (K), and Sodium (Na) |
Frequently Asked Questions
What Soil Analysis Do I Need?
For clients seeking a comprehensive soil evaluation, we recommend the S1 Complete Soil Analysis Package. This package includes pH, Soluble Salts (EC), Organic Matter (OM), Lime, Cation Exchange Capacity (CEC), % Base Saturation, Nitrate-N (NO3), Phosphorous (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na), Sulfate-Sulfur (SO4-S), Zinc (Zn), Iron (Fe), Manganese (Mn), and Copper (Cu). Together, these analyses help determine nutrient availability, fertilizer needs, and potential soil limitations.
In addition, soil texture testing (S11) is recommended for first-time samples and new planting areas because it provides important information about water movement, nutrient retention, and overall soil management. Since soil texture is a relatively permanent soil property, it typically only needs to be tested once unless site conditions change significantly.
Additional specialized analyses may also be available upon request. If you have questions about which test is most appropriate for your situation, please contact the laboratory or your local CSU Extension office for assistance.
Which submission form should I use: Horticultural Soil or Crop Soil?
Use the Horticultural Crops submission form for lawns, turf, vegetable gardens, flower beds, trees, orchards, native plants, native grasses, and pollinator habitats. Use the Crops Soil submission form for agronomic crops such as corn, wheat, oats, potatoes, alfalfa hay, and other grain or forage crops.
When should I test my soil, and how often?
We recommend testing your soil every 2 to 3 years to monitor pH and nutrient levels. For new gardens, problem areas, or intensive crop production, annual testing may be beneficial.
Collect soil samples in early spring before planting and prior to applying fertilizers or soil amendments. Sampling several months in advance allows adequate time for recommendations, such as phosphorus, to take effect before the growing season.
Do you offer soil sample collection services?
Unfortunately, we do not offer on-site sampling services. Homeowners and landowners should collect their own soil samples following laboratory or CSU Extension sampling guidelines. Contact your local CSU Extension office if you need assistance with sample collection procedures.
How can I get my sample to the Lab?
Samples may be mailed to the laboratory or dropped off in person during business hours (Monday through Friday 9 am to 4 pm). Please follow the sample submission instructions and include payment if mailing your sample.
What is a Sample ID?
A Sample ID is a name or number that you assign to your soil sample so it can be uniquely identified by the laboratory and on your test report. The Sample ID helps distinguish samples from different locations on your property and allows you to track results over time.
Examples of Sample IDs include:
- Front Lawn
- Backyard Garden
- Raised Bed 1
- North Pasture
- Orchard Block A
Choose a Sample ID that clearly describes the area sampled. If you submit multiple samples, use a different Sample ID for each location to ensure the results are associated with the correct area.
How much soil do I need to send?
We require about 1 pound of dry, mixed soil. The sample should be a composite made from multiple subsamples collected throughout the area you want to test.
- Lawns: Collect 10 to 15 subsamples from the top 2 to 3 inches of soil and mix them thoroughly.
- Trees, vegetable gardens and flower beds: Collect 10 to 15 subsamples from a depth of 6 or 8 inches and combine them into one representative sample.
- Remove rocks, roots, and debris before submitting the sample.
How do I pay for my soil test?
Payment is due when samples are submitted. Mailed samples must include a check or money order payable to Colorado State University for the total amount due. Samples dropped off in person can be paid for by Visa, Mastercard, or Discover credit/debit card. Purchase orders are accepted from city offices, landscape companies, crop and environmental consultants, schools, and universities.
How will my report be sent to me?
If an email address was provided with your sample submission, your soil test report will be sent by email from Colorado State University quickbooks@notification.intuit.com. Be sure to check your spam or junk folder if you do not receive it. If no email address was provided, the report will be sent by regular USPS mail.
How long will take to get my test results back?
Results will be available within 7 to 10 business days of sample receipt.