Cover Crop Seed & Build the Right Mix

A cover crop mix combines two or more species so each does a different job for the soil — typically a legume to fix nitrogen, a grass for biomass and soil structure, and a brassica to break up compaction. Because they grow together, each species is seeded at only a fraction of its solo (monoculture) rate so the stand isn't overcrowded.

For each species you take its solo seeding rate and multiply by its share of the mix, then add them up: mix rate (kg/ha) = Σ (species solo rate × its % in mix). For example a grass at 100 kg/ha solo, used at 50% of the mix, contributes 50 kg/ha; add the legume and brassica contributions for the total mix rate.

The legume fixes atmospheric nitrogen, feeding the next crop. The grass produces bulk biomass, holds soil, scavenges nutrients and adds organic matter. The brassica sends down a strong taproot that breaks compaction and opens channels for water and air. Blending them gives benefits no single species delivers alone.

Yes — the species shares should sum to about 100% of the mix. The tool shows the running percentage so you can see whether your blend is balanced; if it's well under or over 100%, adjust the shares. The proportions decide how much of each species' solo rate ends up in the field.

Lead with whatever goal matters most: more legume for nitrogen, more grass for biomass and erosion control, more brassica for busting compaction. A common balanced blend is roughly equal thirds, but tilt it toward your aim. The shares simply weight each species' solo rate in the final mix.

The tool multiplies the mix rate (kg/ha) by your field area to give the total seed to buy, and also breaks it down per species so you can order each one. Enter area in hectares or acres and it scales the per-species and total amounts to match your field.

Both work. Drilling places seed at consistent depth for reliable germination and often lets you trim the rate slightly. Broadcasting is faster but usually needs a higher rate and good seed-to-soil contact — broadcast onto a firm bed, then roll or lightly incorporate. Whichever you choose, follow with rolling or incorporation before the cash crop.

Terminate before it competes with or sets seed ahead of the cash crop — usually by mowing, rolling/crimping, grazing or incorporation. Roll or incorporate the residue ahead of planting so it breaks down and releases nutrients. Earlier termination favours a clean seedbed; later termination grows more biomass and nitrogen.

They're solid planning rates. Real rates depend on seed size and quality, sowing method, seedbed, sowing date and your soil-building goal. Use the calculated mix as a starting point, check germination on the seed tag, and adjust — a slightly generous rate is cheap insurance for a thick, weed-suppressing stand.

Yes — enter each species' own solo seeding rate and its share of the mix and it works for any blend, whether two species or a diverse polyculture of legumes, grasses, brassicas and broadleaves. The math is the same; the tool just sums each species' weighted contribution into the mix rate.