Broccoli does best in cool conditions with temperatures between 60 and 70 degrees F. It also needs lots of sunshine and well-drained soil with a neutral to slightly acidic pH—6.5 to 7.0 is ideal. If you live in a climate with very hot temperatures, it’s a good idea to plant your broccoli where it can get some shade during the day to help protect it.
If you start your own broccoli seeds indoors or purchase seedlings from a nursery, let them acclimate a little before you pop them in the ground. Though broccoli is a cool-weather crop, you don’t want to subject tender seedlings to a hard frost. You can put them outside by your house where they will get mostly indirect sunlight, with just a couple hours of direct sunlight each day, and yet be sheltered from frost. After a week, if the threat of frost has passed, you can move your acclimated plants to where you plan to plant them.
When planting broccoli seeds, sow seeds 1/2-inch deep and 3 inches apart. Once seedlings reach a height of 2 to 3 inches, thin them so that plants are 12 to 20 inches apart.
Transplant seedlings and garden center plants 12 to 20 inches apart, in holes slightly deeper than their container depth. Space rows of broccoli 3 feet apart. (Closer spacing produces smaller main heads, but more secondary heads.)
Broccoli plants make good neighbors, offering very little competition to other plants. Even potatoes, which often have a negative effect on other vegetables, grow well alongside broccoli.
There’s some debate as to whether broccoli should be planted with members of its family such as cabbage, cauliflower, and Brussels sprouts. On the one hand, these plants have similar needs, making it easy to tend them when grown together. On the other hand, they attract similar pests and diseases, so if one plant is affected, its possible they all will.
Broccoli plants take up a lot of room, so they grow best planted among plants that don’t need much space and will enjoy some of the shade broccoli provides, such as loose-leaf lettuce, spinach, Swiss chard, and radishes.
Some plants that improve broccoli’s flavor include onions, celery, and potatoes. Additionally, aromatic plants that can help keep pests away include dill, rosemary, basil, mint, garlic, and thyme.
Broccoli sucks up calcium from the soil—which is good for the person who eats it but not for nearby plants that are also calcium lovers. Plants that need little calcium, such as marigolds, beets, and nasturtiums, make good broccoli neighbors and repel pests, too.
Other plants that broccoli thrives among include cucumbers, Swiss chard, lettuce, radishes, spinach, and shallots.
A few plants have a negative effect on broccoli, including: nightshades like tomatoes, peppers, and eggplant; pole, lima, and snap beans; and mustard greens, strawberries, and squash. Because broccoli is a heavy feeder, avoid planting them alongside other nutrition hogs such as asparagus, cantaloupe, sweet corn, and watermelon.
How do you plant your broccoli? What criteria for site selection has worked for you? Do you include companion plants with your broccoli plants? Please share your ideas with us.