How Do You Sow Cover Crops Properly?

Sowing a cover crop takes around fifteen minutes per bed and requires no special tools. The steps are simple, but getting them right — particularly seed depth and soil contact — makes the difference between a crop that covers the ground within two weeks and one that sits in the soil for a month before doing anything useful.

Prepare the Bed First

The most important preparation step is clearing the debris of the previous crop completely. Roots, stems, and old mulch material create air pockets that prevent seeds from making firm contact with the soil. Rake the surface level and remove any large clods. You do not need a fine seedbed — cover crops are more tolerant than vegetable seeds — but a roughly level, debris-free surface is essential.

If the previous crop was heavy and left the surface compacted, a light fork-over or drag with a rake is helpful. On no-dig beds, simply clear surface debris and broadcast directly onto the undisturbed surface.

Seed Rates

Sowing too thinly produces a patchy stand with weed gaps. Use the following rates per square metre as a baseline:

• Phacelia: 2–3g per m²
• Mustard: 3–5g per m²
• Red/crimson clover: 3–4g per m²
• Winter tares: 3–5g per m²
• Field beans: push in individually at 10cm spacing, or scatter at 15g per m²
• Winter rye: 20–25g per m²
• Buckwheat: 10–15g per m²

Broadcasting and Covering

Broadcast the seed evenly by hand, working across the bed twice at right angles to avoid bare patches. For small-seeded species like phacelia and clover, mix the seed with dry sand to improve even distribution. After broadcasting, firm the seed into the soil by pressing with the back of a rake or by walking across the bed on a plank. This soil contact is more important than depth — a seed sitting on loose, airy soil will not germinate reliably.

For most species, a final light rake to cover the seed with 5–10mm of soil is all that is needed. Large seeds like field beans should be pushed in individually to 3–5cm depth or pressed in with a dibber.

Watering After Sowing

If rain is not forecast within two to three days of sowing, water the bed gently. Most autumn sowings have enough natural moisture to germinate without watering, but a late summer sowing into dry soil may sit inert for weeks unless watered. A single good soaking immediately after sowing is usually sufficient.

What to Expect After Sowing

Phacelia and mustard show first signs of germination within four to seven days in warm conditions. Winter rye and field beans take seven to fourteen days in cooler autumn conditions. Clover can be slow — up to three weeks — especially in dry spells. If nothing has emerged after three weeks in reasonable conditions, the bed may need to be resown.