A soil test is the cheapest thing you can do for a food plot. It tells you how much lime and fertilizer the ground needs, so you don't guess. This guide follows extension publications from five universities, listed at the end.

Why test first

Alabama Extension says plants can't use all nutrients when soil pH is low. A basic soil test reports pH plus phosphorus (P) and potassium (K), and gives lime and fertilizer recommendations per acre for the crop you list. University of Tennessee's Craig Harper says most food plot plantings do best at pH 6.0 to 7.0, where nutrients are most available and legumes fix more nitrogen. He also says most sites need lime.

How to take a sample

  • Tools: a soil probe, trowel or spade, and a clean plastic bucket. Kentucky Extension says not to use galvanized or rubber buckets, which contaminate the sample with zinc.
  • How many cores: at least 10 for small areas, up to 30 for big fields (Kentucky). Mississippi State suggests 10 to 12 subsamples for a 1 to 10 acre plot.
  • Where: randomly across the plot. Clear surface residue first (Purdue).
  • How deep: Mississippi State says 0 to 6 inches. Purdue says that for conservation tillage, which includes no-till, you take two samples: 0 to 4 inches for pH and lime, and 0 to 8 inches for fertility. For conventional tillage, 0 to 8 inches covers both.
  • Mix and label: mix the cores into one sample and remove plant material. List the crops you plan to plant, not just "food plot," for better recommendations (Alabama).

When to test

Kentucky says fall (September to December) or spring (February to April) are best, and fall often gets results back faster. Purdue says sample before you lime or fertilize, and keep the same timing each year so results compare. Harper suggests testing in fall for spring plantings, so lime has time to work.

Where to send it

Your state's extension service or university lab. Alabama notes Auburn's lab offers low-cost testing. Mississippi State says you can mail samples to its lab or take them to a county extension office. Kentucky says results usually come back to the county office in 10 to 14 working days.

Reading the results

Alabama Extension says results rate P and K from very low to very high and give lime in tons and nutrients in pounds per acre. Follow the recommendation for your crop.

Lime: how much and how fast

  • Speed: Alabama says lime starts raising pH within a few weeks, but full effects take 6 months or longer. Harper says 5 to 6 months.
  • Amount: Alabama says a plot limed for the first time, or not in a long time, may need 1 to 2 tons per acre or more. Check your test.
  • Work it in or not: Harper says lime works best worked into the soil, especially very acid soil, but surface lime works too, and the benefits of no-till outweigh the small gain from working it in. See no-till food plots on a budget.
  • Quality: Alabama lists standards for ag lime, including at least 90 percent calcium carbonate equivalent.

Ag lime vs pelletized: the budget question

Bagged pelletized or "fast acting" lime, like Pennington Fast Acting Lime, is easy to spread from a bag. Mississippi State Extension says liquid and pelletized lime products are easier to apply but cost more for the same neutralizing effect over time, because you apply less each time and have to apply more often. Alabama says bulk ag lime can be bought delivered or spread by the supplier.

Fertilizer and retesting

  • Harper says nitrogen doesn't last long in soil, while P and K stay longer. Apply P and K per the soil test.
  • Mississippi State says test at first planting and every 2 years after. Kentucky says most fields every 3 to 4 years, and every year for some crops including red clover.

Seed choice

Once the soil is right, see food plot seed, budget vs premium and kill plots vs destination plots. My go-to seed is Domain Outdoor No BS.

Other good options

  • Home pH kits can give a quick pH reading, but a lab test also reports P and K and gives lime and fertilizer rates, per Alabama Extension.
  • Ask your county extension office. Kentucky and Mississippi State both route samples through county offices.

Questions hunters ask

What pH do I want? Harper says 6.0 to 7.0 for most food plot plantings.

Can I lime right before planting? It will start working within weeks, but full effects take 5 to 6 months or more, so earlier is better.

How often should I test? Every 2 years (Mississippi State) to every 3 to 4 years (Kentucky).

Sources

  • Alabama Cooperative Extension, "Soil Testing, Liming, and Fertilizing," FOR-2080: https://www.aces.edu/wp-content/uploads/2021/03/FOR-2080_SoilTestingWildlifeFoodPlots_032921L-A.pdf
  • University of Tennessee, Craig A. Harper, "Soil test now for spring wildlife plantings": https://fwf.tennessee.edu/wp-content/uploads/sites/24/2020/07/Soil-test-now-for-spring-wildlife-plantings.pdf
  • University of Kentucky Extension, "Soil Testing Information": https://extension.mgcafe.uky.edu/woodford/soil-testing-information
  • Purdue Extension, "Soil Sampling Guidelines," AY-368: https://www.extension.purdue.edu/extmedia/AY/AY-368-w.pdf
  • Mississippi State Extension, "Getting the Most Bang for Your Buck," P3102: https://extension.msstate.edu/sites/default/files/publications/p3102.pdf