A Primer on Growing Broccoli

I have never ever been a fan of broccoli. I rarely eat it voluntarily unless it can be dipped in a cheese or chocolate fondue. When it’s served with a meal, I don’t have to say a word as it mysteriously moves from my plate to my wife’s. She lives on the stuff, and it’s always on our shopping list.

This cruciferous vegetable is in the Brassica family that includes arugula, cabbage and bok choy, all known for their health benefits including being anti-inflammatory and high in vitamin C and antioxidants. In fact, just one cup of broccoli provides 100 percent of your daily need for vitamin C and K.

The fact is that this veggie is one of if not the most healthy things you can eat, and as long as you follow a few rules, it’s remarkably easy to grow with each plant producing prolific numbers of crowns with very little human input.

Thomas Jefferson’s garden notes indicate that he was growing broccoli in his garden in May 1767. And earlier the ancient Romans had a love affair with it. The son of Roman Emperor Tiberius was so infatuated with broccoli that he abandoned all other foods for an entire month except broccoli (with cumin, coriander seeds, chopped onion, oil and sun-made wine). The legend also says this binge turned his urine bright green, making him a standout among the gladiators.

Last May I went to a local community plant sale where I donated as many perennials as my garden was willing to give up. While going back to see what was left, there was a lonely four-pack of broccoli seedlings that I grabbed for a couple of dollars. I was seeing not a healthy vegetable but brownie points at home. The four-pack sat on the back steps for weeks but finally got planted in the trial garden.

The root ball of each plant was gently teased open to encourage the roots to spread, the planting holes dug, some time-release fertilizer added to the hole, the plants instated into the soil, firmed in and watered. Over the summer I added some organic fertilizer in rings around the plants and worked into the soil. I also remembered from my experience with other plants in the same family that the one evil thing to watch for were caterpillars that devour the foliage, leaving behind ragged holes and munched edges of leaves. They can be hand picked or the foliage sprayed with Bt, which is an organic insecticide used on many caterpillars.

The caterpillars — cabbage worms, cabbage loopers and diamondback worms — never showed up. I was lucky. But if I plant broccoli in the same spot this year, the chances of getting hit are pretty high. This is why crops in this family, including cabbages, should be planted in a different location every year and never together.

The spindly plants grew and grew, developing their thick branches. In spite of being stepped on a few times, each plant matured and began sending up florets. These allegedly tasty crowns, if not harvested in time, turn into flowering florets that are well past their edible prime. When it was obvious to even a black thumb what they were, I coerced my wife into the trial garden and in my horticultural glee exclaimed to her, “Look! Real homegrown broccoli!” and the brownie points started to add up.

As each crown got to a harvestable size I’d slice it off with a sharp knife and bring it into the kitchen at dinner time. More brownie points. But one of broccoli’s other miracles is that each time you cut a floret off, a new one, a bit smaller, emerges for a double and sometimes a triple harvest. Lots of brownie points.

At the end of the season the entire plant is yanked from the soil and added to the compost pile where the composting microbes devour it in glee and I get my 8 square feet of trial garden space back.

Now in addition to watching for the caterpillars (or their telltale black pellet droppings) there is another important thing about growing broccoli: As with other vegetables, if you plant all your transplants at once — surprise, surprise — they all mature at once.

It is difficult to get your transplants at the garden center and do a succession planting over the summer because all the plants will probably mature at the same time since they were all grown at the same time. The solution? Grow your own transplants from seed and grow several different varieties with different maturity times. But that’s not all. You also need to do succession seeding about two to three weeks apart so your plants and varieties mature at different times. But don’t ignore the cell packs at the garden center. Always buy a few as backups.

This weekend would be the perfect time to start your first set of seeds, and they’ll need to be transplanted into peat pots when large enough. Then in late April they can be set outdoors. This can be done even earlier as long as you protect them against frost and freezes by covering them with row cover cloth.

With the right choice of varieties and a good seed sowing schedule you’ll have broccoli to harvest into the summer and well into the fall. Be mindful of heat though. Broccoli is not a friend of late summer heat, but you can find varieties touted as being heat tolerant and heat resistant. Also don’t plant all your broccoli in one spot. Scatter the plants around the garden to reduce any disease or insect issues from wiping out all your plants.

Harvest the crowns early in the day when they’re firm and tight. Never let the soil around the plants dry out; keep the soil well watered but keep mulches away from the main stems to deter slugs. Slug damage can often be confused with caterpillar damage, but only the caterpillars will leave behind the telltale droppings.

Get the crowns into the fridge quickly where they can be stored in the crisper for several days at 34-36 degrees. Our winter broccoli often comes from California where it’s packed in refrigerated train cars and shipped cross country at 32 degrees with high humidity.

If you’d like to know more about growing broccoli, take a look here in Johnny’s Selected Seeds’ library where there’s information on planting, the different varieties and much, much more including broccoli’s close relative, broccoli rabe: bit.ly/3lbB8cn. Broccoli and broccolini can also be grown indoors as microgreens, which can be cooked or added to salads.

For those who want to know more about the culinary uses of broccoli there’s a great piece here from Kitchn: bit.ly/3TojDSH. This article covers the use and recipes for broccoli, broccolini, broccoli rabe and Chinese broccoli.

Remember that this is a cool-season crop so it does best early and late in our growing season. This doesn’t mean that it’s limited to these times as you can find types that are noted as “heat tolerant.” You can also sow seed again in the garden in late July for fall harvesting, but keep in mind not to sow all your seed at once or you’ll end up harvesting all at once. Fine if you only want to freeze the crowns but not if you want a long season of fresh broccoli. Keep growing.

A few thoughts about climate change and how it may affect your gardens. A number of years ago the U.S. Department of Agriculture updated its plant hardiness zones to reflect our longer growing seasons. It’s been a while since those updates, but for a couple of years I think it’s been safe to say we have added a week at the front end and a week at the tail end of the growing seasons on the East End. But there is a big caveat. The extended growing seasons as a result of the warming earth does not mean there won’t be early frosts and freezes as well as late ones. Don’t be lulled into thinking that our first frost free date (April 24 give or take) is a guarantee. It can take just one hard frost or freeze to wipe out tender plants, even those that have been properly hardened off.

The solution, if you don’t have one or more cold frames, is to keep a supply of row cover material handy that can be thrown over rows or blocks of early veggies or garden plants. The row cover can just be laid on top to “float” or you can quickly or easily put the covers over wire hoops that are available at garden centers and online, often sold as “low tunnel” hoops. When the threat has passed, the covers are simply rolled up or folded and stored for their next use. As a bonus these row covers can also be used to protect a number of crops from insect invaders and to offer some shade in the dog days of August. The most well known brand is Reemay, and it’s sold bulk by the yard or precut in packages. You can see how it’s used here: bit.ly/2XShJ2e.