5 Tips for Growing Broccoli in Containers and Raised Beds

When I first started gardening, the crop that I was most excited about growing was broccoli.

I decided on a springtime planting in one of my raised beds. Though I nurtured that plant obsessively –I got a pretty stalk with lots of green – a head never sprouted. It was a most frustrating experience.

But after much more practice in the garden coupled with a ton of research, I’ve decided to give broccoli another try. Here are some of the things that I will do to make sure I get a bumper crop of broccoli this year. I’ll let you know how it goes!

Choose your growing season wisely.

Opting for growing broccoli in the spring of Chicago was probably a mistake. An inconsistent season weather-wise, growing spring crops in Chicago – where it can snow even in April – is a difficult proposition. About the only thing I can ever grow successfully in the spring is greens. Anyway, back to broccoli. This year, I decided to try growing broccoli in the fall. Since broccoli can take 50-60 days from transplant to harvest, starting plants in August gives them a long enough runway to give them a good growing season in the waning days of summer so they can mature in cooler fall days. (Broccoli that matures during cool weather tastes sweeter than at any other time.) Also, broccoli can withstand temperature down to 20 degrees, so you can still be potentially harvesting it in December – depending on Chicago’s erratic weather, that is.

Plant it at the right time.

To figure out when to plant broccoli is easy-peasy. If you are direct sowing in your garden, plant seeds 85 to 100 days before the average first fall frost in your area. According to the Farmers Almanac, the first frost date in Chicago is Oct. 29 – hence the perfect time to plant seeds is in early August. So, get those seeds in the ground right now. If you decide to transplant a seedling rather than direct sowing, plant it 10 days to the “days to maturity” for the variety you’re growing and then count backwards from your expected first fall frost date. For Waltham, the variety of broccoli I’m growing, it takes 50-60 days to maturity from transplant. So, the ideal time to plant a Waltham transplant would be late August to early September.

Choose the right size container – and space properly in your raised bed.

One of the biggest mistakes novice container gardeners make is either choosing a too-small container or planting crops too closely together in their raised bed. For just one broccoli plant, you’ll need a 3- to 5-gallon container that is at least 12 inches deep; I’m growing two plants per each 10-gallon fabric container. (I like fabric containers with handles because they allow me to chase the light in the garden and move plant around with ease.) In a raised bed, plant each sprout 15-18 inches apart.

Pick the right soil, water consistently and plant in full sun.

Broccoli needs loose, well-draining soil to grow properly, so choose soil wisely. The plants prefer slightly acidic soil, rich in organic nutrients so add compost to the planting hole, as well as a good layer on top. Make sure when you’re planting to tamp down the dirt in the pot or in the bed because brassicas like compacted soil. However, broccoli is prone to root-rot so it’s really important to water consistently to help avoid root rot – you want to make sure the soil is always damp, but you don’t want to overwater as broccoli don’t like wet feet. And last but not least, broccoli plants need a LOT of sun – at least six hours a day. The tricky thing about broccoli is that though it requires full sun, the plant will also start to bolt at temperatures above 80 degrees. This is where having your plants in fabric containers with handles come in handy – you can move the naturally cooler containers around to either sunnier or less-hot spots in your garden.

Fertilize and manage pests consistently.

Broccoli is a heavy feeder so it’s vital that you fertilize them at planting with a well-rounded fertilizer (I like Espoma Garden Tone) and a couple of times during the seasons after that. Broccoli also attracts pests like cabbage loopers. You can control them with BT or Bacillus thuringiensis, which is a soil-born bacterium that kills caterpillars like that cabbage loopers that love to munch on your broccoli but won’t harm beneficial insects.

<span class="has-inline-color has-vivid-red-color">Tequia Burt</span>
Tequia Burt

Tequia Burt is a Chicago-based editor, writer, content creator, and brand storyteller with 20 years of experience. In addition to being the Editor in Chief of Backyard Chicago Garden, she is the Founder-CEO of Content[ed.], which provides custom content and strategy to businesses.