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Cover Crop Seed Calculator
Pounds of cover-crop seed for your area by crop, the bags to buy, the cost, and coverage per bag.
Cover Crop Seed Calculator
Chlorova · updated for 2026
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The seeding rates here are typical clean-seed broadcast rates per crop, but real seed is sold at different purity and germination levels, so a low-test bag is worth sowing heavier than this figure assumes. Rates also shift with how you sow, since a drill places seed more efficiently than a hand broadcast, and a mix is usually sown at a blend of each component rather than full rates of both. Treat the pounds as a starting point, sow the ends and edges a touch thicker, and follow the specific guidance on the seed bag you actually bought.
Sowing a cover crop by feel means either a bare, patchy bed or a heavy bag you paid good money to over-apply. This cover crop seed calculator turns the area you want to protect into the pounds of seed it takes, by crop, then shows the bags to buy, the cost, and how many square feet one bag covers. Pick the crop for its typical rate, enter your area and bag size, and you know the seed order before you ever shake the spreader hopper.
Working Out a Cover Crop Order
- Choose the cover crop so the calculator loads its typical seeding rate per area.
- Enter the total bare area you want to sow, measured in square feet.
- Set the bag size in which that seed is actually sold to growers.
- Enter the full price that you pay for one single bag of seed.
- Read the total number of pounds of seed the whole area really needs.
- Check how many square feet of ground a single bag will cover.
- Note the bag count and total cost so you can order in one pass.
How the Seed Rate Is Worked Out
The rate is written as pounds per thousand square feet, so the seed needed is simply the area divided by one thousand, then multiplied by that crop rate. One bag covers the bag weight divided by the rate, scaled back up to a thousand square feet, which tells you how far a single sack stretches. Bags and cost then round the seed up to whole sacks, because a partial bag of seed is not something you can actually buy.
The crop picker supplies the only variable, a mid-range clean-seed broadcast rate: about two pounds for crimson clover, three for hairy vetch, eight for the small grains rye and wheat, and twelve for chunky field peas. Those numbers are per-thousand references that match common grower guides, not a hard rule, since sowing method, seed test and whether you are broadcasting or drilling all move the true rate. Order by the calculator, then fine-tune toward the specific guidance printed on the seed bag in your hand.
Worked Example: Five Hundred Square Feet of Clover
- You are sowing crimson clover over a bare garden area of about five hundred square feet.
- Crimson clover here carries a light broadcasting rate of two lb per thousand.
- The total seed you need is 500 ÷ 1000 × 2 = just 1.0 lb.
- That seed is sold here in five-pound bags at roughly twenty dollars each.
- One five-pound bag at this light rate covers about 2,500 sq ft of ground.
- So a single bag is already far more seed than the whole plot truly needs.
- That sets your total cost at just one bag, or roughly twenty dollars.
- The leftover clover seed can bank another bed or two for next fall.
Typical Broadcast Rates by Crop
Representative clean-seed broadcast rates for the crops offered here, shown as pounds per thousand square feet. The crop picker uses the same figures, so switch crops in the calculator and every result re-solves off that one rate.
| Cover crop | lb per 1,000 sq ft | One 5 lb bag covers |
|---|---|---|
| Crimson clover | 2 | 2,500 sq ft |
| Hairy vetch | 3 | 1,667 sq ft |
| Cereal rye | 8 | 625 sq ft |
| Winter wheat | 8 | 625 sq ft |
| Field peas | 12 | 417 sq ft |
Key Terms
- Seeding rate
- The pounds of seed per unit area that a crop needs for a full, even stand.
- Broadcast
- Scattering seed over the surface by hand or spreader, usually at a higher rate than drilling.
- Drill
- Placing seed at a set depth and spacing, which uses seed more efficiently than broadcasting.
- Nitrogen fixer
- A legume such as clover, vetch or peas that feeds nitrogen back into the soil for the next crop.
- Clean seed
- Seed freed of chaff and weed seed, the assumption behind the pounds-per-area rates used here.
Sowing Enough Without Wasting Seed
- Legume rates look tiny because the seed is small, so do not second-guess a one-pound clover order on a big bed just because it feels light in the bucket.
- A drill uses seed more sparingly than a broadcast, so if you are hand-scattering, the true rate sits toward the top of the range, not the middle this tool assumes.
- In a mix, do not add full rates of each component, since the total is usually a blend, and stacking full singles is how growers over-seed and waste money.
- Seed test and purity matter more than the label rate, because a bag at lower germination needs heavier sowing to land the same final stand in the ground.
- Sow the edges and problem corners a little double, since broadcast spread thins out at the borders and those bare strips are where weeds slip in first.
Common Mistakes & Fixes
- Confusing a per-acre rate with a per-thousand-square-foot one and ordering ten to forty times the seed.
- Treating a grass rate as a legume rate, then wondering why the clover came up in thick, weak clumps.
- Sowing a mix at full single rates and paying for seed you scattered far too heavily.
- Assuming every bag is clean seed, then under-sowing a low-test lot that needed a heavier pass.
- Skipping the border overlap, so the outside of the plot stays bare all season while the middle is crowded.
When to Use This (and When Not To)
Use it any time you are sowing a green manure or winter cover and want the seed order and cost up front, from a few raised beds to a half-acre plot. It handles straight-line seeding rates, not a blended multi-species mix, so for a complex pollinator or soil-building blend, budget each component with this tool and combine them yourself. For cash-crop planting densities rather than cover, reach for the plants-per-square-foot or seed-packet calculator instead, which think in stands per bed.
Cover Crop Seed Calculator: Frequently Asked Questions
How much cover crop seed do I need per square foot?
It depends on the crop, which is why the calculator asks. As a guide, clover needs about two pounds per thousand square feet while heavy field peas want a dozen, so divide the crop rate by a thousand and multiply by your area to get the pounds.
How many pounds of seed per 1,000 square feet?
Roughly two pounds for crimson clover, three for hairy vetch, eight for rye or wheat, and twelve for field peas. These are typical broadcast rates, and the calculator multiplies whichever crop you pick by your area to return the exact order.
Is a broadcast rate the same as a drilled rate?
No, drilling places seed at depth and spacing and uses less, while broadcasting wastes some on the surface. The figures here lean toward broadcast, so if you are drilling you can often sow a little lighter than the calculator suggests.
How do I handle a seed mix?
Do not simply add full rates of every component, since that over-seeds the plot and your budget. Work out each crop separately with the calculator and then use a fraction of each, so the blended total lands at a sensible single-crop density.
Why does the bag count round up?
Because seed is sold in whole bags, so a job that needs one and a third pounds still requires you to buy the full sack. Rounding up also leaves you a little spare for borders, thin spots and a follow-up patch, which is a good thing to have on hand anyway.
Do these rates match the bag I bought?
Usually close, but always check the label, since seed is sold at different purity and germination levels that shift the true rate. The calculator gives a reliable order of magnitude, and the specific guidance printed on your actual bag is what you should fine-tune to before sowing.
Sources & Further Reading
- Cover Crop Seeding Rates and Establishment — USDA Natural Resources Conservation Service. Basis for the per-crop broadcast seeding rates used here.
- Selecting and Sowing Small Grains and Legumes — Penn State Extension. Underpins the broadcast-versus-drill and nitrogen-fixer guidance on this page.
- Managing Cover Crop Seed and Purity — Michigan State University Extension. Source of the seed-test and purity cautions in this calculator.
Chlorova Gardening Team
Builds, checks and documents every tool we publish
Chlorova editorial review
Checked against extension-service publications
Formula verified against published references · Updated