Soil Test Desk: test in fall, lime in fall, grow better in spring
Take 8 to 10 cores per bed about 6 inches deep, mix them, and send a pint to your state lab. Fall is the best time: lime needs at least 3 months to work, and labs are not swamped. Most vegetables want a soil pH of 6.0 to 6.8.
Enter your result in the live desk to see which crops need lime, which are fine, and which should never get it. It saves your pH and test date in your browser and shows how many weeks lime has before your zone last spring frost.
Take a garden soil sample this fall, check your pH against each vegetable and fruit, and add lime at least 3 months before planting. Target and lime-below pH for each vegetable from extension tables.
Take the sample
Take 8 to 10 cores per garden area, about 6 inches deep, mix them, and send about a pint. Fall is best because lime needs time to work.
- Split the garden into areas and sample each one separately
- Wait 6 to 8 weeks after any lime or fertilizer
- Sample when the soil is dry enough to crumble
- Take 8 to 10 cores 6 inches deep in a zigzag and mix them in a clean plastic bucket
- Bag about a pint, label it, list your crops on the form, and send it to the lab
Read the report
Start with pH and the lab lime rate. Aim for 6.0 to 7.0 for most vegetables. Follow the lab, not generic bag instructions.
- Enter your pH and test date
- Write down the lime or sulfur rate the lab gave you for your bed area
- Check phosphorus and potassium against the lab scale
- Ask for soluble salts if you use a lot of manure compost
Amend this fall
Lime goes on at least 3 months before planting. Compost and manure fit fall too. Do not lime potatoes or blueberries.
- Spread lime at the lab rate on beds that read below target
- Skip lime on potato and blueberry beds
- Spread about 1 inch of finished compost and fork it into the top 6 to 8 inches
- Add any raw manure now, not in spring
- Cover amended beds with shredded leaves or a cover crop
Follow up
Vegetable beds need a test every 1 to 2 years. Lime fades, so plan to retest and reapply every few years.
- Log what you added, the rate, and the date
- Set a retest reminder for next fall
- Rotate crops by pH need next spring
Get a real lab test
Home kits and meters give rough readings. A lab test gives your exact pH plus how much lime and fertilizer to add. Most state labs charge about $15 to $30, and a few test for free.
Find your state extension soil lab below. Check the lab page for current fees and mailing steps. Links checked October 2026.
- Alabama: Auburn University Soil, Forage and Water Testing Lab
- Alaska: UAF Cooperative Extension soil testing guidance (no in-state public lab)
- Arizona: University of Arizona Extension list of testing labs (no in-state public lab)
- Arkansas: University of Arkansas Soil Testing and Research Lab (Free for Arkansas residents (checked Oct 2026))
- California: UC Master Gardener list of soil testing labs (no in-state public lab)
- Colorado: Colorado State University Soil, Water and Plant Testing Lab
- Connecticut: UConn Soil Nutrient Analysis Laboratory ($18 standard test (checked Oct 2026))
- Delaware: University of Delaware Soil Testing Program
- District of Columbia: UDC Environmental Quality Testing Laboratory
- Florida: UF/IFAS Extension Soil Testing Laboratory
- Georgia: UGA Agricultural and Environmental Services Laboratories
- Hawaii: University of Hawaii Agricultural Diagnostic Service Center
- Idaho: University of Idaho Analytical Sciences Laboratory
- Illinois: University of Illinois Extension soil testing guidance (no in-state public lab)
- Indiana: Purdue list of nutrient testing labs (no in-state public lab)
- Iowa: Iowa State Extension soil testing guide for home gardeners (no in-state public lab)
- Kansas: K-State Soil Testing Lab
- Kentucky: University of Kentucky Regulatory Services soil testing
- Louisiana: LSU AgCenter Soil Testing and Plant Analysis Lab
- Maine: University of Maine Soil Testing Service
- Maryland: University of Maryland Extension soil testing guide (no in-state public lab)
- Massachusetts: UMass Soil and Plant Nutrient Testing Laboratory ($20 routine analysis (checked Oct 2026))
- Michigan: Michigan State University Soil and Plant Nutrient Lab
- Minnesota: University of Minnesota Soil Testing Laboratory
- Mississippi: Mississippi State University Extension soil testing
- Missouri: University of Missouri Soil and Plant Testing Laboratory
- Montana: Montana State University Extension list of soil testing labs (no in-state public lab)
- Nebraska: Nebraska Extension list of soil testing labs (no in-state public lab)
- Nevada: University of Nevada, Reno Extension soil testing guide for home gardeners (no in-state public lab)
- New Hampshire: UNH Extension Soil Testing Services ($25 standard gardening test (as of April 1, 2026))
- New Jersey: Rutgers Soil Testing Laboratory
- New Mexico: New Mexico State University soil testing guidance
- New York: Cornell soil testing guidance (Cornell recommends Dairy One Agro-One)
- North Carolina: NCDA&CS Agronomic Services soil testing (Free April 1 to November 30, 2026; $5 from December 1, 2026)
- North Dakota: NDSU Extension lawn and garden soil guide (NDSU Soil Testing Laboratory)
- Ohio: Ohio State Extension soil testing for horticulture (no in-state public lab)
- Oklahoma: Oklahoma State University Soil, Water and Forage Analytical Lab
- Oregon: Oregon State University Soil Health Lab
- Pennsylvania: Penn State Agricultural Analytical Services Lab
- Rhode Island: URI Cooperative Extension Gardening Information and Soil Testing
- South Carolina: Clemson Agricultural Service Laboratory ($6 standard soil test (checked Oct 2026))
- South Dakota: SDSU Extension list of soil testing labs (no in-state public lab)
- Tennessee: University of Tennessee Soil, Plant and Pest Center
- Texas: Texas A&M Soil, Water and Forage Testing Lab
- Utah: Utah State University Analytical Laboratories home soil testing ($25 routine test (checked Oct 2026))
- Vermont: UVM Agricultural and Environmental Testing Lab ($17 routine test (as of July 1, 2023))
- Virginia: Virginia Tech Soil Testing Laboratory
- Washington: WSU Extension soil testing guide for home gardeners (no in-state public lab)
- West Virginia: West Virginia University Soil Testing Laboratory
- Wisconsin: UW-Madison Soil and Forage Lab
- Wyoming: University of Wyoming Extension soils guidance (no in-state public lab)
- Puerto Rico: University of Puerto Rico Agricultural Extension Service
What each crop wants
Target is the pH labs aim for. Lime below is the pH under which acidity is likely to hurt growth. Potatoes prone to scab want 5.0 to 5.2 and should not get lime.
- Asparagus: target pH 6.8, lime below 6.2. Keep it under 7.0.
- Beans (snap): target pH 6.2, lime below 6.0. Keep it under 7.0.
- Beets: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Broccoli: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Brussels sprouts: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Cabbage: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Carrots: target pH 6.0, lime below 5.5. Keep it under 7.0.
- Cauliflower: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Celery: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Collards: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Sweet corn: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Cucumbers: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Eggplant: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Garlic: target pH 6.4, lime below 6.0. Keep it under 7.0.
- Kale: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Kohlrabi: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Leeks: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Lettuce: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Cantaloupe and melons: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Okra: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Onions: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Parsley: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Parsnips: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Peas: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Peppers: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Pumpkins: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Radishes: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Spinach: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Squash (summer and winter): target pH 6.5, lime below 6.0. Keep it under 7.0.
- Strawberries: target pH 6.2, lime below 5.8. Keep it under 7.0.
- Sweet potatoes: target pH 6.2, lime below 5.5. Keep it under 7.0.
- Swiss chard: target pH 6.5, lime below 6.2. Keep it under 7.0.
- Tomatoes: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Turnips: target pH 6.5, lime below 6.0. Keep it under 7.0.
- Watermelon: target pH 6.2, lime below 5.5. Keep it under 7.0.
- Blueberries: target pH 4.8, lime below 4.5. Keep it under 5.5.
Sources
- University of Delaware Extension, Measurement and Management of Soil pH for Crop Production in Delaware
- Rutgers NJAES, Soil and Nutrient Management
- Cornell, Nutrient Guidelines for Commercial Vegetable Production
- Clemson HGIC, Soil Testing
- University of Georgia Extension, Soil Testing for Home Lawns, Gardens and Wildlife Food Plots
- Virginia Tech Extension, Soil Sampling for Residential Areas
- Purdue Extension, Collecting Soil Samples for Testing
- NC State Extension, Fall Is the Time to Lime
- Oklahoma State Extension, Soil Test Interpretations for Vegetable Crops
- Colorado State Extension, Vegetable Gardens: Soil Management and Fertilization
- University of Maryland Extension, Organic Matter and Soil Amendments
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- How to take a garden soil sample
- How to read your soil test results
- When and how to add lime to a garden in fall
- Best soil pH for vegetables
- How to use compost and manure in fall beds
- How to put the garden to bed by zone
- Garden to Bed: fall closeout checklist
- Fall Leaves Desk
- Cover Crop Desk
- First frost date
- Winter gardening hub