Fast-growing annual cereal cover crop that produces abundant leafy growth and a dense fibrous root system. Oats help cover bare soil, take up excess nutrients, add organic matter, and compete with cool-season weeds. They make a particularly easy cover crop for vegetable beds because they are less persistent than winter rye.
When to sow: Sow in late summer through early fall for winter cover, ideally August through September in the Portland area. Spring sowing is also possible. Fall-planted oats may winter-kill during sufficiently cold weather, leaving a mulch over the soil.
How to terminate: If they survive winter, mow, cut, or chop down in spring before seed heads mature. For easiest incorporation or chop-and-drop, terminate while plants are still green and tender. Allow a couple of weeks for residue to begin decomposing before direct-seeding small vegetable seeds into the bed.
One pack covers 100 square feet. From Concentrates, Inc.
Avena sativa, Morton Oats seed
How to Use Your Cover Crop & Native Seed Packets
Each seed packet is measured to cover 25 sq ft or 100 sq ft, depending on the size you chose.
Sowing Instructions
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When to sow: Fall is ideal in Portland. The soil is still warm for germination, and fall rains keep seedlings watered. Some seeds (like meadowfoam or clovers) can also be spring-sown.
How to sow:
- Rake the soil lightly to create good seed-to-soil contact.
- Scatter the contents of the packet evenly over the area (don’t worry about perfect spacing).
- Gently press or rake seeds in so they make contact with the soil. Do not bury deeply — most native and cover crop seeds need light to germinate.
- Water: Fall rains usually do the job, but water lightly if the weather turns dry.
What to Expect
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Traditional Cover Crops (rye, peas, fava, daikon, crimson clover, buckwheat, mustard): Grow quickly, protect soil, and build fertility. In spring, chop them down or mow before they set seed. Some (like rye) can also be crimped into a mulch.
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Living Mulches (red fescue, dwarf yarrow, creeping thyme, low clovers): These stay low and provide long-term weed suppression and ground cover. Shear lightly as needed, but they don’t require replanting every year.
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Pollinator Wildflowers (Clarkia, poppy, gilia, flax, meadowfoam, coneflower, blanketflower): Not classic cover crops, but they add beauty and attract bees, butterflies, and beneficial insects. Many reseed naturally.
Spring & Summer Management
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Chop-and-drop: Cut plants at the base and leave them as mulch (peas, fava, clovers).
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Mow: Use on ryegrass or cereals to turn them into quick mulch.
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Crimp: Flatten tall rye or grains at flowering to create a long-lasting weed barrier.
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Shear perennials: Yarrow, thyme, and sedges can be trimmed back after bloom.
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Self-seeders: Flowers like poppy, clarkia, and meadowfoam will often reseed themselves. Leave some seed heads if you want them back next year.
Quick Tips
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Cover crops = soil builders.
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Living mulches = weed suppressors.
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Wildflowers = pollinator magnets.
Tulle or row cover can protect young seedlings from birds and slugs until established.
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