Broccoli At A Glance
- Reliable cool-season annual for full sun garden location.
- Start seeds indoors 4-6 weeks prior to the last frost date.
- Prefers well-drained, organically rich soil with regular moisture.
Planting Instructions
Start seeds indoors as you would other vegetables.
- Use pre-moistened, seed starting mix free from fertilizer in trays, packs, or pots.
- Sow seeds 1/4 in. deep, place trays on consistent bottom heat of 70°-75°F, and cover tray with a plastic dome or wrap to help retain moisture but uncover and spritz with warm water as needed until seeds germinate in 5-10 days. (Seeds can be pre-soaked for eight hours prior to sowing to enhance germination)
- After emergence, uncover, remove from bottom heat, and place seedlings in bright direct sun or under grow lights at cool room temperature.
NOTE: Broccoli seedlings can be prone to damping off. Maintain proper sanitation, avoid over-watering, and promote good air circulation for seedlings.
- As seedlings develop true leaves, up-pot into slightly larger containers with clean, fresh, pre-moistened potting soil and water as needed.
- Transplant seedlings deep to allow buried stems to grow roots, which yields stronger plants.
- If seedling growth stalls out, fertilize with water-soluble 4-6-8 or 6-6-6 food at 1/2 strength, once per week.
- When plants are large enough, harden off for 7-10 days prior to planting out about two weeks prior to the last frost.
- Start new seeds by direct sowing in mid-summer for fall crops with seeds 1/4 - 1/2 in. deep, then thin to 12 in. apart with 2-3 ft. between rows.
Growing
- Prefers well-drained soil in a sunny location.
- Plant seedlings out early as they will tolerate cool temperatures. It needs to grow in the cool spring weather, especially in warm climates, in order to form large broccoli heads.
- If you plant early and extremely low temperatures are expected, simply cover your plants with a row cover, sheet of plastic or old bed sheet to protect the plants from the frost.
- Maintain consistent soil moisture, especially during hot or dry weather.
- Side-dress plants with 1 Tbs. 10-10-10 or 3-5-3 fertilizer blended with fresh compost when plants are 6-8 in. tall or use a water-soluble fertilizer such as 4-6-8 food once every two weeks, starting 2-4 weeks after transplanting.
Harvest and Troubleshooting
- Broccoli plants are cut and come again crops, which means when the main central head is harvested, side shoots will develop smaller harvestable heads for several weeks if the weather remains cool.
- Hybrid broccoli varieties are bred with disease resistance and temperature adaptability, but following proper cultural practices will yield the best crops with the least number of issues.
- Rotate brassica crops with legumes like peas or beans to help prevent potential diseases.
- Cutworms, aphids, flea beetles, and larvae of cabbage looper can be problematic pests. Regular monitoring and avoidance measures like using floating row covers, proper garden sanitation, and preventative pesticide treatments allow for adequate pest management.
- Hot weather and warm soil can lead to bolting (flowering). Avoid this by planting early, mulching well, utilizing row covers or fleece grow tunnels, and applying consistent water.
- Buttoning, or poor heading, is due to temperature fluctuations, planting too early, inadequate soil moisture, high temperatures, or a combination of these conditions.
