Cover Crop Mix Calculator

Cover crop mixes rarely get sown at each species' full pure-stand seeding rate — crowding several species into the same field means each one only needs a fraction of what it would take growing alone. This calculator starts from the percentage of grasses, legumes, and brassicas you want in the blend (normalized so they always sum to 100% even if your entries don't add up cleanly), then multiplies each species' pure-stand rate by its normalized share and by a flat 50% mix-reduction factor — a standard rule of thumb reflecting that multi-species stands need less seed per species than a monoculture would. That gives a blended seeding rate in lbs/acre, which is then scaled up by your acreage for total seed quantity and cost, using your blended average seed price per pound.

As a bonus, the calculator estimates nitrogen contribution from the legume component by multiplying its normalized fraction by a conservative mid-range fixation figure of 80 lbs N/acre at full stand — a ballpark for common legumes like clover, vetch, or field peas, not a substitute for a soil test or species-specific fixation data. Keep in mind the 50% mix-reduction and 80 lb N/acre figures are fixed assumptions in this model, not tunable per species, so treat the results as planning-stage estimates: actual establishment, termination timing, and soil conditions will shift real-world seeding needs and nitrogen credits up or down.