How to Grow Broccoli

Jordan Tony Feb 16, 2022

In our continued exploration of plants in the cabbage “family,” which are actually all the exact same species, Brassica oleracea, we can’t leave out broccoli. In the case of broccoli, brassica oleracea was bred over the years to exaggerate its tightly packed clusters of flower buds. The word broccoli comes from the Italian word broccolo, which roughly translates to “cabbage sprout.” Romans are believed to have first cultivated broccoli. It mostly remained in that region until the Italian diaspora when immigrants introduced it to North America, where it’s widely eaten today.

In some circles, broccoli has a reputation for being a bland, boring clump of green. This is partly due to how some people prepare it, but it is also true that much of the broccoli from the grocery store has minimal flavor and depth on its own. If frozen bags of broccoli florets are your only experience with the vegetable, you'll be blown away when you taste the flavor of homegrown broccoli. It is sweeter, more complex, and more flavorful than anything you can get from the store. If you’re interested in giving homegrown broccoli a try, read on to learn the best practices for small-scale organic production.

Starting from Seed The best way to ensure healthy broccoli that will outcompete weeds is to give your plants a head start by starting them indoors four to six weeks before you transplant them into your garden. You can also buy trays of broccoli seedlings at most garden centers and nurseries. If you are growing the seedlings yourself, wait until they are about 3 or 4 inches tall and then start “hardening off” your plants.

Hardening off is the process of acclimating your transplants to the temperature and direct sunlight of the outdoors by leaving them outside during the day and bringing them back in at night. You should harden off your broccoli transplants for about four or five days before planting in your garden.

Broccoli Growing Conditions The best time to transplant broccoli into your garden is around four weeks before the average last frost date in your growing zone. Ideally your broccoli will be ready for harvest before the strongest heat of summer which can stress broccoli plants and lead to a host of problems. You can also plant broccoli in late summer for a fall crop. If you live in a growing zone with relatively mild winters, broccoli can even be overwintered for an early spring harvest.

Because the primary edible part of broccoli is the flower head, you want your soil to have a good mix of phosphorus, nitrogen, and potassium, which will help promote flower and leafy growth. Using cover crops or incorporating healthy compost will ensure that your soil nutrition is well balanced. The standard recommended spacing between broccoli plants is 12 to 18 inches, but if you have a deep, compost-rich soil, you can get away with closer spacing than that. In our raised beds we plant broccoli about 10 to 12 inches apart.

Broccoli Pests Broccoli suffers from many of the same pests and diseases as other crops in the cabbage family. In my experience, the primary broccoli pests are small green caterpillars referred to as Cabbage Whites (Pieris rapae). The name “Cabbage White” describes the adult morph of the insect which is a small white butterfly. If you have ever grown vegetables in the cabbage family, you have almost certainly seen them fluttering around your garden.

The best method of control for these pests is row cover or insect netting that prevents them from laying their eggs on your broccoli in the first place. If this is not a suitable option for your garden, you can inspect your broccoli leaves every few days and pick off any caterpillars that you find. If all else fails and your crop is being severely damaged by caterpillars, you can use an application of the organic pesticide Bacillus thuringiensis (BT) to knock back their population.

Broccoli Harvest and Storage The point at which you harvest your broccoli will depend on the variety you are growing. If you are growing the traditional broccoli heads that we see in American grocery stores, you'll want to harvest when the color of the florets start to change from light to dark green and the individual buds swell to about the size of a pencil tip. After this point they’re in danger of flowering, and although still perfectly edible, they won’t have the same texture or shelf life.

Make sure to cut them about 1 or 2 inches below the base of the head. This will stimulate side shoots and give you a second harvest of bite-sized florets. Other varieties like sprouting broccoli or broccoli raab are harvested when the flower buds start to swell up and open. These varieties will also produce side shoots if you cut the heads and leave the rest of the plant intact.

For a bonus harvest, you can eat the leaves of your broccoli, which have a very similar taste and texture to collard greens. We usually do this after harvesting the head and side shoots. Remember that if you are growing your broccoli for a fall harvest, allowing it to experience a few frosty evenings will stimulate sugar production and lead to a sweeter, more tender harvest. Freshly harvested broccoli will last in the refrigerator for up to two weeks, but if you grew more than you can use in that time frame, you can chop it into florets, bag it and freeze it.

Now that you’re well equipped to cross the frozen broccoli off of your grocery list and grow your own, it’s time to crack open a seed catalog and pick out some varieties for your Spring garden. Although homegrown broccoli is flavorful enough to eat right off the stalk, I recommend giving Danielle Prewett’s broccolini and lemon risotto recipe a try with your first harvest.