Delaware · Soil test

Delaware soil-test fertilizer recommendations

Uses University of Delaware recommendations. Checks of the implemented rates, rules and screens are still in progress. Lime has its own live calculator for Delaware with method-specific lab inputs.

See Delaware recommendations → Delaware lime guide

Critical soil-test levels

  • P: critical 25 FIV (Mehlich-3 reported as UD-FIV)
  • K: critical 25 FIV (Mehlich-3 reported as UD-FIV)
  • Mg: critical 40 FIV (Mehlich-3 reported as UD-FIV)

Per Delaware — UD Cooperative Extension Soil Testing Program (Mehlich-3 / UD-FIV) — below the critical level, a yield response to the added nutrient is expected.

Crops covered

Delaware — UD Cooperative Extension Soil Testing Program (Mehlich-3 / UD-FIV) rates these crops in Delaware:

AlfalfaAlfalfa - New Seeding (UD ALS)Alfalfa/Grass Mixed - New Seeding (UD AGS)Annual or Italian Ryegrass - New Seeding (UD IRS)Annual or Italian Ryegrass Forage (UD ARF)Annual or Sweet Bromegrass Forage (UD ABF)BarleyBarley Forage (UD BAF)Bermudagrass - New Seeding (UD BGS)Big Bluestem - New Seeding (UD BBS)Brassica/Grass Mix - New Seeding (UD BGS)Cereal Rye Forage (UD RYF)Chicory/Grass Mix - New Seeding (UD CGS)CornCorn Silage (UD CSI)Corn silageEastern Gamagrass - New Seeding (UD EGS)FescueForage Sorghum (UD FSF)Grass / forageGrass hayGrass/Legume Mix - New Seeding (UD GLS)Hemp and Kenaf for Fiber (UD HMF)Hemp and Kenaf for Fiber (UD KNF)Hemp f or Seed (UD HMS)Hops (UD HOP)Indian Grass - New Seeding (UD IGS)Kentucky Bluegrass - New Seeding (UD KBS)Little Bluestem - New Seeding (UD LBS)Malting Barley (UD MLT)OatsOrchardgrass - New Seeding (UD ORS)PasturePearl Millet (UD PMF)Perennial Ryegrass - New Seeding (UD PRS)Red Clover - New Seeding (UD RCS)Reed Canarygrass - New Seeding (UD RGS)RyeSericea Lespedeza - New Seeding (UD SLS)Small Grain/Legume Forage (UD SLF)Smooth Bromegrass - New Seeding (UD SBS)SorghumSorghum Silage (UD SOG)Sorghum silageSorghum/Sudangrass Hybrid (UD SSF)SoybeansSpring Oats (UD SOF)Sudangrass (UD SGF)Sunflower (UD SFL)Switchgrass - New Seeding (UD SGS)Tall Fescue - New Seeding (UD TFS)Teff (UD TFF)Timothy - New Seeding (UD TMS)Triticale Forage (UD TRF)WheatWhite Clover - New Seeding (UD WCS)Wildlife Food Plots - Deer (UD WDR)Wildlife Food Plots - Game Birds (UD WGB)Wildlife Food Plots - Rabbits (UD WRB)Wildlife Food Plots - Turkey (UD WTR)Wildlife Food Plots - Waterfowl (UD WWF)Winter Oat Forage (UD WOF)Winter Wheat Forage (UD WWF)

More crops via alternate guides selectable in Delaware: Mid-Atlantic Commercial Vegetable Production Recommendations 2026/2027.

Published source: Delaware — UD Cooperative Extension Soil Testing Program (Mehlich-3 / UD-FIV)

Frequently asked

What soil-test method does Delaware use?

Delaware — UD Cooperative Extension Soil Testing Program (Mehlich-3 / UD-FIV). Zone Forge cites the publication on every recommendation.

Is the Delaware soil-test calculator free?

Yes — the Delaware soil-test recommendation calculator is free and needs no signup. Enter your lab values for source-cited P and K; Delaware's live lime calculator is available separately with its own required lab inputs.

Can Zone Forge calculate a Delaware lime rate?

Yes — the free soil-test calculator covers source-cited P and K. Delaware also has a live lime calculator on Zone Forge that uses the state's published method. Open the Delaware lime guide or lime calculator for tons of CaCO3-equivalent per acre.

Zone Forge reads every Delaware soil test in its own state's language, then builds source-cited fertilizer and a live lime calculator and full variable-rate prescriptions. See the science →