Broccoli is a surprisingly complicated vegetable and can be hard to grow. It is one of the top vegetables that our readers said they had difficulty growing—and for good reason! But, if you are up for the challenge, follow our helpful growing guide below!
General notes: Planting timing and watering details are very specific. Temperature is also a big factor. Long periods of hot weather may cause heat stress, which damages the plant and its development.
Standard broccoli prefers cooler temperatures and grows best in the spring and fall. For this reason it is known as a “cool season” vegetable.
Getting Started: Two Methods
1) Starting Seeds Indoors & Transplanting
- Spring planting: Start seeds indoors 6 to 8 weeks prior to your last frost dates.
- Be sure not to expose spring transplants to frost.
- Summer planting (for a fall crop): Slightly less time is needed for a fall crop. This is because seedlings tend to grow faster in the summer than in the spring. Start seeds 6 weeks prior to planting. Calculate your plant date by counting back approximately two months from your first frost dates.
- Bear in mind that broccoli may tolerate a light frost when it is planted as a fall crop.
- Standard broccoli is a large plant, so place transplants 18 to 24 inches apart.
- Space rows three feet apart.
2) Direct Seeding Outdoors
- Sow three broccoli seeds one half-inch deep every foot in row.
- Space rows 18 to 36 inches apart.
- Once the plants are established, thin them to one plant for every foot of the row.
Consistent soil moisture will produce the best heads. At a minimum, supply one inch of water per week. There are two critical watering periods:
1) When the transplants are being established, just after planting.
2) As the head is developing.
Well-drained, fertile soil with a pH of 6.0 to 7.5 (slightly acidic to slightly alkaline.
Broccoli plants prefer full sun, but may tolerate some shade.
Before transplanting, work well-rotted manure or aged compost into the soil. When plants are about 4 inches tall, side dress the plants by working more compost into the soil several inches away from the roots.
Broccoli is a heavy nitrogen feeder, making nitrogen-rich compost a good source for the nutrient.
Common Diseases & Pests
Black rot, alternaria, cabbage looper, cabbage worm, flea beetle, and root maggots. To control insect pests, place summer-weight row covers over the plants at time of transplanting.
When harvesting broccoli, cut the center head before its flower buds open. The plant will produce secondary shoots if left in the ground. Be sure not to cut only the center head and not the small secondary shoots which will start to emerge a few inches down on either side of the stalk. Harvesting shoots as they develop will encourage more growth.
Temperature is a crucial factor in determining whether the plant will develop a head properly. Optimal temperature for broccoli head production is 65 to 70 degrees Fahrenheit, making spring and fall crops the most successful.
It can be challenging to achieve a perfect head with standard broccoli.
Here are some other varieties to consider:
1) Leaf broccoli. This type may be harvested at leaf-stage or left to develop as small florets emerge;
2) Broccoli rabe. This type is easy to grow and matures fast.
3) Chinese broccoli (Gailon crossed with mini broccoli). This type produces many side shoots over a long period. It grows well even under stress from heat and drought.
4) Winter broccoli (also known as late-sprouting broccoli). This variety forms its spears of florets best in temperatures under 50 degrees Fahrenheit.
Community Is Important!
Besides our guide, we would like to underscore the importance of community with gardening. Be sure to talk with local growers and have conversations about what to do and when.
You can always “wing it” and learn from your mistakes, but when we share and lear from each other may get better results faster!
Tell Us Your Experience
Have you tried growing broccoli before?
What are some challenges that you faced?
Let us know in the comments below!