Legume inoculants contain living rhizobia selected for particular groups of legumes. The correct group matters: an inoculant sold for clover should not be assumed to inoculate peas, beans, alfalfa, or cowpeas. Use this chart to narrow the choice, then confirm the exact crop on the current product label.
Commercial names and crop lists can vary. The seed description and inoculant label are the controlling sources for treatment status, compatibility, rate, storage, expiration, and planting interval.
Legume and inoculant-group chart
| Legume group | Common examples | Inoculant group to look for | What to verify | Current Grow Organic products |
|---|---|---|---|---|
| Clovers | Crimson, red, white, berseem, strawberry, subterranean and related clovers | Clover-group inoculant listing the planted species | Species on the label; raw versus coated seed; treatment life and storage | Alfalfa-Clover Inoculant — treats 50 lb |
| Alfalfa and medics | Alfalfa and annual medics | Alfalfa/medic-group inoculant | Crop listing, soil pH suitability, seed treatment compatibility and planting interval | Alfalfa-Clover Inoculant — treats 50 lb |
| Peas, vetches and lentils | Field peas, Austrian winter peas, common or hairy vetch, lentils and often fava beans when listed | Pea/vetch/lentil-group inoculant | Every species in a mixture; whether fava bean is specifically included; storage and rate |
Pea Vetch Lentil Inoculant — treats 100 lb Pea, Vetch & Lentils Inoculant — treats 1,500 lb |
| Garden and field beans | Common beans such as snap, dry and lima types when listed | Bean-group inoculant | Bean species, current crop list and compatibility with any seed treatment | Bean Inoculant — treats 1,500 lb |
| Soybeans | Soybean | Soybean-specific inoculant | Soybean listing, lot and expiration, field history and treatment compatibility | Soybean Inoculant — treats 300 lb |
| Cowpeas, peanuts and lespedeza | Cowpeas, black-eyed peas, peanuts, lespedeza and related crops when listed | Cowpea/peanut/lespedeza-group inoculant | Exact crop, rate, seed coverage, storage and planting interval | Cowpea, Peanut & Lespedeza Inoculant — treats 100 lb |
| Specialty legumes | Lupines, sunn hemp and other less common legumes | Only a product that specifically lists the crop | Do not substitute a familiar group without crop-specific directions | Check all current seed inoculants; use only a product whose current label lists the crop. |
Check whether the seed is already inoculated
Before treating seed, read the product description and bag information.
- Raw seed has no rhizobia treatment and may need a compatible inoculant where effective bacteria are not already present.
- Pre-inoculated or rhizobia-coated seed has received a compatible treatment, but storage conditions and treatment life still matter.
- Coated seed is not automatically inoculated. A coating may contain lime, nutrients, colorant, or another material without living rhizobia.
- Seed mixtures may contain several legumes. One inoculant group may not cover every species in the mix.
If the treatment status or inoculant group is unclear, verify it before adding another product.
Application checklist
- Match the inoculant to every legume being planted.
- Check the lot, expiration, package coverage and storage directions.
- Use only the adhesive, moistening method or mixing procedure allowed by the label.
- Coat seed evenly without soaking or damaging it.
- Keep treated seed cool and shaded.
- Plant within the stated interval into a prepared seedbed with suitable moisture.
- Do not combine with fungicides, fertilizers or other seed treatments unless compatibility is documented.
When re-inoculation may be considered
Re-inoculation may be considered when raw seed is being planted, when the field lacks a reliable history of the compatible legume, or when an existing treatment is outside its stated storage or planting life. Do not assume more inoculant improves properly treated seed. Follow both the seed and inoculant directions.
Check nodulation
After establishment, examine representative healthy plants at the crop-appropriate stage. Dig roots rather than pulling them so nodules remain attached. Cut several nodules and use crop-specific guidance to interpret their internal color. Poor nodulation can result from the wrong inoculant, lost viability, incompatible treatments, dry or saturated soil, unsuitable pH, high available nitrogen, compaction, or weak crop establishment.
Shop Compatible Inoculants
Choose by crop group first, then select a package that covers the amount of seed being planted. Always confirm every crop on the current product label.
- Small mixed-legume and garden batches: Garden Combination Mix — treats 8 lb or Garden Combination Mix — treats 50 lb.
- Clovers, alfalfa and medics: Alfalfa-Clover Inoculant — treats 50 lb.
- Peas, vetches, lentils and listed fava beans: Pea Vetch Lentil Inoculant — treats 100 lb or Pea, Vetch & Lentils Inoculant — treats 1,500 lb.
- Garden and field beans: Bean Inoculant — treats 1,500 lb.
- Soybeans: Soybean Inoculant — treats 300 lb.
- Cowpeas, peanuts, lespedeza and other crops listed on the label: Cowpea, Peanut & Lespedeza Inoculant — treats 100 lb.
For another package size or a crop not listed above, compare all current seed inoculants and verify the current label before treating seed.
Continue planning
- Legume Inoculants: Rhizobia, Nitrogen Fixation and Application
- Nitrogen-Fixing Cover Crops
- Compare current inoculant products
- Browse legume cover-crop seed
- Use the Cover Crop Solution Chart
Always use the current product label and seed description as the controlling sources.
Continue cover crop planning
After matching seed to inoculant, use the Cover Crop Solution Chart for selection and the Cover Crop Seed Rate Calculator for area-based quantity. The seed and inoculant labels control compatibility and application.