Brassicas include broccoli, cabbage, cauliflower, Brussels sprouts, kale, collards, and kohlrabi. They share many cool-season needs, but harvest stage, spacing, and sensitivity to heat or cold differ. This family guide provides the common framework; use the crop-specific guide and packet for final directions.
Choose from broccoli, cabbage, cauliflower, kale, and kohlrabi seeds.
Choose the crop and harvest
| Crop | Harvest | Planning point |
|---|---|---|
| Broccoli | Main head and, for some varieties, side shoots | Time head formation for cool conditions. |
| Cabbage | Dense terminal head | Choose maturity and storage type for the intended season. |
| Cauliflower | Curd | Steady growth and variety-specific blanching needs matter. |
| Kale and collards | Leaves | Can be direct sown or transplanted and harvested over time. |
| Brussels sprouts | Axillary buds along the stalk | Long season; often best when maturity occurs in cool weather. |
| Kohlrabi | Swollen stem | Harvest before the stem becomes oversized and fibrous. |
Spring and fall timing
Brassicas generally perform best with cool but moderate growing conditions. In climates with a short spring, starting indoors can give plants time to establish before heat. For fall harvest, count backward from the expected harvest window and allow for slower growth as days shorten. Some crops tolerate light frost, but tolerance depends on crop, variety, growth stage, and acclimation.
Start indoors or direct sow
Start transplants in clean media about four to seven weeks before the planned outdoor date, following the packet. Provide strong light, avoid overwatering, and harden gradually. Kale, collards, kohlrabi, and some broccoli or cabbage crops can also be direct sown when soil and weather are suitable.
Use the frost-date calendar and soil-temperature chart to set the starting date.
Soil, spacing, and fertility
Choose full sun and well-drained soil with consistent moisture. Obtain a soil test before adding large amounts of fertilizer or lime. Space according to the crop and desired harvest size: crowding can reduce head size and airflow, while excessive spacing wastes bed area. Mulch can moderate moisture and soil temperature after plants are established.
Rotate the plant family
Broccoli, cabbage, cauliflower, Brussels sprouts, kale, collards, kohlrabi, mustard, radish, turnip, and rutabaga are related. Rotating away from the entire family—not just one crop—can help manage persistent problems such as clubroot and black rot. A four-year interval is commonly recommended where feasible, but garden size and local disease history affect the plan.
Common problems
- Flea beetles and cabbage worms: Monitor early. Row cover can exclude some pests when installed before they arrive, but remove or manage it when pollination is required.
- Bolting or poor heads: Temperature stress, transplant stress, and variety timing can contribute.
- Clubroot: Avoid moving contaminated soil and rotate the full plant family.
- Black rot: Use clean seed, avoid working wet plants, and manage infected residue according to extension guidance.
- Uneven growth: Check moisture, root condition, spacing, and soil fertility rather than assuming more fertilizer is always needed.
Harvest and next crop
Harvest at the crop's intended stage. Broccoli side shoots may continue after the main head; kale and collards can be picked leaf by leaf; cabbage and cauliflower are generally single-head harvests. After harvest, use the succession planting guide to decide whether another crop fits the remaining season.
Brassica questions
Are radishes and turnips brassicas?
Yes. They belong to the same plant family and should be included when planning rotation for family-specific diseases.
Why did a plant bolt instead of forming a head?
Temperature, transplant age, stress, day length, and variety can contribute. Review the crop-specific conditions rather than assuming one cause.
Can all brassicas be direct sown?
Many can, but transplanting may provide a timing advantage in short spring or fall windows. Cauliflower and long-season crops often benefit from careful transplant planning.
Do row covers solve every pest problem?
No. They can exclude certain insects when installed early and sealed, but they do not treat soilborne disease and require crop-appropriate ventilation and pollination management.
Should I remove lower leaves?
Remove severely damaged or diseased material when useful, but healthy leaves power growth. Routine heavy stripping is not a universal care practice.
Continue planning your seed garden
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