Library · Field, beds & planting
Cover Crop Selector.
Cover Crop Selector
Match the cover crop to the goal: fix nitrogen, build organic matter, smother weeds, break compaction, attract pollinators, fumigate soil. 30+ species filtered.
The cover crop families
| Family | Strength | Examples |
|---|---|---|
| Legumes (Fabaceae) | Nitrogen fixation (50-200+ lb N/acre) | Crimson clover, hairy vetch, field pea, sun hemp, cowpea, alfalfa |
| Grasses (Poaceae) | Biomass + organic matter; erosion control; weed suppression | Rye, oats, wheat, sorghum-sudangrass, millet, barley |
| Brassicas (Brassicaceae) | Biofumigation; deep tap-rooting; rapid growth | Tillage radish, mustard, rapeseed, turnip |
| Buckwheat (Polygonaceae) | Fast (30-day) summer cover; pollinator forage; phosphorus mobilization | Common buckwheat (only one species) |
| Mixes | Stack benefits; multi-season function; resilience | Rye + vetch (classic); 5-12 species "cocktail mixes" |
Why mix species
The biggest insight from regenerative agriculture in the past 15 years: multi-species cover-crop "cocktails" outperform single-species covers for almost every goal. A 6-species mix with one of each functional group gives:
- Better risk distribution (one species fails, others compensate)
- Multiple root depths (deep tap + shallow fibrous + medium)
- Multiple flowering times (extended pollinator support)
- Diverse rhizosphere microbiology (each species recruits different microbes)
- Multiple nutrient cycling pathways (N fixation + P solubilization + K mining)
Termination methods
| Method | When | Pros | Cons |
|---|---|---|---|
| Mowing / flailing | Pre-flowering for soft cover; mature for residue | No soil disturbance; quick | Many species regrow; need follow-up |
| Crimping (roller-crimper) | Anthesis (flowering) | Excellent termination; thick mulch; no-till plant into | Timing critical; specialized equipment |
| Tillage / incorporation | Pre-flowering; 2-3 weeks before next crop | Reliable; mineralizes N quickly | Soil disturbance; OM oxidation; fuel use |
| Tarping (occultation) | 2-4 weeks under black plastic | No till; chemical-free | Plastic cost; only practical small scale |
| Grazing | When palatable | Income from livestock; nutrient cycling | Need fencing + livestock; trampling damage if over-grazed |
| Winterkill | Hard frost | Free; predictable in cold regions | Only works for cold-sensitive species (oats, peas, buckwheat) |
| Herbicide (glyphosate) | Mature | Reliable | Chemical; not organic-compatible; resistance |
Free under CC BY 4.0. Cite as "OAT Cover Crop Selector (openagriculturetechnology.com)". Species data drawn from SARE Cover Crops handbooks and USDA NRCS conservation publications.