- Kale plants like to grow in a rich soil, high in organic matter with a slightly acidic pH (5.5 – 6.5 pH). You’re growing it for the leaves, so the high nitrogen content provided by organic matter is crucial.
- The optimal soil temperature for planting is 60 – 65 degrees F. All varieties prefer cool temperatures and will be sweetened by a touch of frost. Hot weather turns kale bitter.
- Kale can be direct seeded in the garden or started indoors and set out as transplants. Start plants indoors about 6 weeks before your last expected frost date. Kale seeds germinate quickly in warm soil and should be up within 5 – 8 days.
- Cover seeds with about ½ in. of soil and don’t allow the seeds to dry out before germinating. Plants will grow more slowly outdoors than indoors under lights.
- Transplant seedlings after danger of frost. Set plants out with about 16 in. spacing between plants. This gives them room to spread out and still allows for air circulation.
- You can direct seed in cold climates, in the spring, as soon as the soil can be worked and the soil temperature is at least 45 F. Kale matures quickly, in about 2 months or less, so if you prefer you can start your plants later or even plant multiple crops by succession planting.
- In warm climates, kale can be direct seeded in late summer / early fall, as well as in the spring. A winter crop of kale in warmer climates can be much sweeter than a summer crop.