Growing Broccoli

Growing Broccoli
Broccoli ready to be harvested

Growing broccoli is a staple in my garden. It is part of the cabbage family like kale, cauliflower, collard greens among others. To learn about some members of the cabbage family: Broccoli is extremely high in vitamin K and C and has lots of minerals, as well as phytonutrients and flavonoids that protect against different cancers. It also has more protein than the average vegetable and a low calorie count. You can eat the leaves; I wash them, freeze them and add them to smoothies. These whole family  are highly nutritious vegetables, and broccoli is definitely a superfood. 

Starting Plants

To grow broccoli you need transplants in the north east during the spring to accommodate the shorter spring  growing season. If it warms up early the heads bolt (opening into full fledge flowers) before the heads are able to develop. Transplants should be started six to seven weeks before the last spring frost prior to planting them outdoors. Seeds will germinate when the temperatures are as low as 40°F, which means that, technically, you could direct seed them in the spring but they will germinate faster if the soil is warmer. It is best to keep the plants in an environment of 60°F and in direct sun to avoid them getting leggy. Once the plants have four to five true leaves, then transplant them outdoors, planting about 18” to 20” apart.

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For a fall planting, you can direct seed them from late May to late July or midsummer, depending on location and how fast the frost arrives. Once the plants have enough development, then place them in the correct location with proper spacing. To learn all about organic gardening you can purchase

Plant Care

Broccoli grows in full sun and cooler weather. It can get up to three feet tall depending on the variety and it can spread between two to three feet apart. The leaves tend to be greenish, while other varieties have a bluish cast.

The soil should have good amounts of organic matter but don’t over fertilize. Too much fertilizer can cause hollow stems to develop. The plant will then not be able to hold itself up or be strong enough to hold the head. Mulching them will not only prevent weeds and keep moisture even but also prevent root damage, as the roots are shallow, and they can get damaged when weeding.

A well-drained soil is necessary to prevent diseases. They do well with a pH ranging in the area of 6.0 to 7.5, which means they tolerate some alkalinity. The plants do need good amounts of moisture for proper development. Once the plants begin to produce heads, then add a side dressing of organic fertilizer or water them with compost tea.

Side shoots of broccoli. Cabbage white butterfly (cabbageworm) laying eggs on the leaves.


Different varieties will mature at different stages. Some are early and will mature in early summer versus others maturing in mid to late summer and other varieties are best suited for fall. Therefore, plant different varieties to stretch the harvest season from May all the way into August. Heat-tolerant varieties should be planted in the spring versus the fall. The head should be between six to ten inches in diameter when harvested.

Once the main head develops, and before it opens, you should harvest them. Broccoli, unlike other plants, continues to produce from the side shoots. The heads will be small and abundant, and you can continue to harvest them for another month. You can choose to let some of these side shoots open into full bloom and let the bees and other insects enjoy their nectar. The fall harvest will tolerate a light frost but not a hard frost.

Growing broccoli seedlings under cloth cover in the spring.

Insects and Pests

This whole family has a lot of pests that are a real nuisance. Growing broccoli can be a real challenge unless you use cloth row covers to keep the pests out. From the time I place the transplants outdoors in the early spring I cover the seedlings. I do remove the cover once it gets too hot. If I did not, then the plants would get overly tall and the heads would take extra-long to develop or be relatively small. Once the protective cloth is removed, you have to apply BT or be constantly checking for larva and eggs from multiple pests. In particular, it is likely to be the cabbageworm.

In the fall, you can leave the protective covers on for the length of the season as the days get cooler. The plants may get big, since they are planted in the late summer. You can also spray with BT early on for the fall planting, and once the temperatures drop more in September, cover them before the heads begin to develop. I choose to keep them covered and to then air them out every day, since I’m dealing with a small planting versus a large farm area where this may not be practical.

Other insects that attach this family and make growing broccoli a real challenge are flea beetles, cabbage aphids, cutworms and cabbage root maggots. To avoid a buildup of diseases, I recommend a three year rotation of the whole family. If you do get clubroot, then add some additional lime to raise the pH above 7.2, and this will help kill off the disease.

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