Fast-growing, cold-hardy Asian green that also works well as an edible cover crop. Tatsoi forms dense, low rosettes of dark green leaves that quickly shade bare soil and help suppress weeds. Its fine, branching roots hold soil and take up nutrients during the rainy season. Young leaves can be harvested for salads or cooking while the remaining plants continue to cover the bed.
When to sow: Sow from late summer through early fall for fall and winter cover. Tatsoi thrives in cool weather and tolerates frost, making it particularly well suited to Portland winters. It can also be sown in late winter or early spring.
How to terminate: Harvest it! Cut whole rosettes at soil level as needed, or mow or chop remaining plants before they flower and set seed. Leave roots in the soil to decompose and cut foliage on the surface as mulch. Because tatsoi is a brassica, avoid using it immediately before or after other brassica crops if you are rotating crops to reduce pest and disease problems.
From Territorial Seed Company. 99% germination rate.
Mustard, Tatsoi seeds
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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Understanding Pack Options
🌱 Planting Coverage Options
Planting coverage refers to the amount of seed needed to reliably plant a given area under typical Pacific Northwest conditions.
- 1 sq ft coverage = enough seed to plant approximately one square foot
- 5 sq ft coverage = enough seed to plant approximately five square feet
Coverage is based on recommended spacing, expected germination, and normal thinning, not exact seed counts and not final plant size.
For some crops (especially tomatoes, squash, and other large plants), seeds are intended to be started in pots and later transplanted. In those cases, coverage reflects the number of starts most gardeners need, rather than the space mature plants will occupy.