A head for perfection: Broccoli is a tricky vegetable to grow, requiring precise timing and soil prep (2024)

I hold out hope there are people who know more about growing broccoli on the Gulf Coast than I do.

I’d have to believe, at least, that there are gardeners out there who are as motivated as I am to capture and cook the perfect head of broccoli. Leafy kale and collards are the soul of winter, but what a bright warm treat, on a cold evening, to sauté a big bouquet of crisp, densely packed green flowerheads. It’s like an apertif of spring.

I’ve bought broccoli in the grocery store, and it was, on occasion, as good as what I’ve managed to grow myself. But growing my own broccoli has special rewards.

I know that if I grow it right, the heads will be fresh and crisp, and the flavor won’t have trickled out in the floor of a semitruck driven in from California.

I also get to try exceptionally rich-flavored strains of broccoli that you simply can’t buy from the grocery store, like Calabrese, the "original" sprouting Italian broccoli, or broccoli raab, with flavor as dark and dense as pure chocolate.

Not least, there is that sneaking moment of pride I enjoy whenever a perfectly formed head emerges from the mass of glaucous leaves.

But if the Benevolent Society of Gulf Coast Broccoli Growers has developed the perfect broccoli growing system for our soils and climate, they’re not sharing their secrets. So I’ve committed myself over the past few years to making as many mistakes growing broccoli as I possibly can (sometimes, the only way to figure out how to do something right is to figure out how many ways to do it wrong).

I’ll admit to an abundance of failures, but what I think I know is this: Timing is the issue with broccoli in our climate. It’s nearly impossible to grow a good head of broccoli when daytime temperatures exceed 80 or so degrees. Even mild (for us) warm weather (compounded, perhaps by high night temps) leaves broccoli stunted, stringy and bitter.

And as the weather warms, a proliferation of cabbage loopers and other pests descend by the gadzillions to sample every cole-relative you have in your garden. The leaves and flowers of broccoli will be, I promise you, among their favorite desserts, and every tiny branch will seem to hide another worm.

Along the Gulf Coast, that pretty much eliminates an edible broccoli harvest from mid-April through late September.

Fortunately, broccoli not only enjoys cool weather, it’s moderately tolerant of of genuinely cold weather. While it’s not nearly as hardy to cold as collards or cabbage, it’s generally tougher than turnips or mustards. So with a cloth cover on the coldest nights (when temperatures drop below 26-28 degrees), it’s usually not difficult to keep it standing and growing right through the winter, from October through March.

But you want more than simple survival: You want that big pile of leaves and stalk to begin producing a flowering head that you can harvest. And that’s where the real calculation begins.

In my experience, broccoli just doesn’t head up very well during the shortest, coldest days of the year, from mid-December through the first of February. If I were a more patient gardener, I suppose I could just sit on my hands and enjoy a brief harvest in late February and March, when the return of spring puts all plants in mind of flowering (and reawakens the appetites of cabbage worms).

But it seems a shame to waste all these cool broccoli-growing days of December and January, when pests are non-existent and flower heads, when they do form, are at the peak of flavor. (I know, because I just harvested a sweet and crisp bouquet and cooked them up last evening).

As a result, I keep playing with varieties and planting seasons, so that the broccoli is large enough to start forming flowerheads while the days are still reasonably long, and the nights still reasonably warm — but AFTER the worst of the heat and insects are gone. That seems to be the period from mid-October to late November. Once they’ve started sprouting, they seem to continue to develop regardless of the temperature or daylight, so I’ll get sprouts for the better part of 5 months.

Standard hybrid broccolis such as Green Comet will generally take around 70 days from seed to produce a head in fall. If you plant big, robust transplants in your garden in early to late October, you’ll be sitting pretty. The hard part is finding good transplants for sale that late in the year.

Sowing your own is the best resort, but you’ll want to start them in late summer — certainly before Sept. 15 for standard varieties, and preferably in late August. Since broccoli has limited tolerance for heat and is very vulnerable to late-summer insects, I’d advise starting in pots on a porch, or even inside on a cool but bright windowsill.

The alternative is to experiment with varieties that produce more quickly, in 50 to 60 days, such as the sprouting DeCicco or Green Goliath. These could shave as many as two weeks off the time to harvest, so they can be reasonably sown in September.

Many of these short-season broccolis have a stronger tendency to produce an abundance of smaller, but still very delicious, secondary sprouts after the main head has been harvested. These secondary sprouts may continue to produce for months, a real advantage in the home garden.

The best of these "sprouting" broccolis is, perhaps, the oldest — "Calabrese" or "Italian Green Sprouting." While it takes a little longer to produce its first head, it seems to sprout more prolifically and for a longer period, and also appears to be more tolerant of weather and insects. You give it a try, compare it with DeCicco and Green Goliath, and tell me what you think.

For those who do have the patience to wait for spring harvest, you might consider fall-planting of very long-season varieties, such as Purple Sprouting. While Purple Sprouting is said to have extraordinary cold tolerance, it’s slower than Christmas to form heads — even if you plant in September, you may not see your first head until late February.

I haven’t even bothered to experiment with the Romanesco broccolis, which resemble green byzantine cauliflowers and are much fawned over in some circles. These seem to be among the most poorly adapted broccolis for our climate, however, requiring an extraordinarily long season of bland temperatures — neither too hot nor too cold. If you break the Romanesco code, drop me a line and fill me in.

f you’re a really bold broccoli lover, you should at least once try broccoli raab, which is one of the easiest and fastest of the broccoli-like vegetables, often ready to harvest a month and a half after harvest. That means it can be planted two or three times, starting in October, and continuing into early February.

All of those subtle flavors broccoli lovers treasure in conventional varieties are intensified tenfold in broccoli raab — you’ll either come to crave it or swear to never eat it again. It’s almost as spicy as mustard, as deliciously bitter as turnip greens, with a distinctive hickory-like nuttiness. Raab is a point of pride at traditional Italian restaurants — Gianmarco’s in Birmingham does a superb job with its raab, if you’d like to swing by and try some this winter.

Broccoli raab is actually only a cousin of conventional broccoli, and might best be described as a turnip with broccoli ambitions. The flower buds are small, and rarely form heads bigger than your thumb. But raab is eaten leaves, stems, flowers and all, so it’s a very space-efficient vegetable.

Cutting broccoli a second time

Unless you’re a farmer trying to make a buck selling to Walmart, you don’t want to harvest your entire broccoli plant at once. Virtually all home-grown varieties of broccoli produce a large main head, and a number of separate side shoots. Harvest the main head with only a few inches of stem, and the side shoots will quickly develop into moderately large secondary heads. You’ll lengthen your broccoli harvest by months.

That’s why old-fashioned sprouting broccoli varieties, such as Calabrese and DeCicco, are generally better for home gardeners. These older varieties weren’t bred for the cut-it-all-at-once grocery store market. So while they never produce an extraordinarily large single head, they produce a much larger volume of smaller heads over many months.

Soil for broccoli-growing

Since you’ll be growing your broccoli through the wet days of winter, it’s a good idea to plant in slightly raised beds, rich in fast-draining but moisture- and nutrient-retentive leaf mold.

Broccoli is also more sensitive than some vegetables to our normally acidic soils, so add lime or plenty of crushed oyster shell to bring your pH up to about 6 or 6.5.

As with all winter vegetables, the soil will also need to be well-fortified with nutrients. It can be a little tricky to add chemical fertilizers or organic fertilizers in winter, so ideally, you’ll have prepared your beds in summer with organic fertilizers such as manures, blood meal or cottonseed meals. A good sprinkling of ashes in October and November may also help, on several accounts.

Broccoli has no tolerance for drought. During most winters, that’s not a big problem, but watch your plants closely and water regularly during extended periods of dry, warm days in October and November, and again in late February or March.