How to grow broccoli

Broccoli is the most prolific member of the brassica family and the easiest to grow.

By Mat Pember
Broccoli is the most prolific member of the brassica family and the easiest to grow - just beware its mean, green nemesis, says Mat Pember.
It's April and we're a step closer to autumn and the fresh change we all need. For the patch, this is the first real opportunity to get intimate with cool-season crops. This month, we shack up with an old favourite: broccoli, of the brassica family. Of the heading brassicas, which include cauliflower, cabbage and Brussels sprouts, broccoli is the simplest to grow. Add to that, it's the only one that regenerates, delivering a prolonged harvest.
But don't fall into a false sense of security because, despite the advantages broccoli has over its brassica counterparts, it's still a target of the cabbage white butterfly, or rather its caterpillar (see one-minute skills below). The level of warfare with the critter is generally determined by the variety of broccoli you grow. Larger heading varieties, known as Calabrese broccoli, require a longer growing and maintenance period than sprouting varieties or broccolini. This gives the caterpillar a larger window of opportunity to strike, and more cover to hide, so bear that in mind when selecting your variety.
April can throw up a few surprises weather-wise so it's best to propagate seeds in individual pots stored on a tray. It's important that your seedlings are easily transported; if a heatwave strikes, take your tray indoors to a cooler place. Otherwise, it's outdoors in the day, indoors at night.
Once planted, water seeds twice daily in short, sharp bursts until germination occurs. As the seedlings begin to mature in the pots, water daily for the first month, then get set for a transplant into the patch. Timing is everything - avoid hot, sunny planting days and planting before a prolonged wet slog is predicted. A wet garden at this time of the year is a highly active one for snails and slugs that will favour new arrivals.
Broccoli is one of the most nitrogen hungry crops out there, so incorporate plenty of compost and slow-release organic fertiliser into the patch before planting. If possible plant seedlings where your summer beans previously grew because they would have fixed the soil with a reserve of nitrogen that will be appreciated by your broccoli. Also, ensure the patch is free draining.
Mulch the patch once the broccoli is in. This helps insulate the coolness in the soil, and an even soil temperature is a bonus for any plant. Use pulverised pea straw, lucerne or sugar cane and mulch to a depth of two to three centimetres.
Water your broccoli two to three times a week and, as always, make sure it's first thing in the morning to keep night-trawling pests - in search of moisture - away from the patch. If you're growing in pots, water every second day in the absence of rainfall - potted plants dry out much quicker.
Get into the habit of feeding your plants every fortnight with liquid seaweed fertiliser. Broccoli can go into flower when stressed - either through lack of water or nutrition - so this helps develop a strong, large head. You should see the first peep of it after two months of growth.
Once you've deemed a head large enough for the dining table, cut it off at the first junction of leaves on the stem, then await the next batch. The first head is always the largest, while successive harvests, known as florets, resemble broccolini.
It's possible to gather three or four sets of florets over a two- to three-month period before you get just pretty yellow flowers. By that stage, the caterpillars, snail, slugs and UFP (unidentified flying pests) will have more than likely overrun the plant, but by then your patch is probably ready for the next change of season anyway.
One-minute skills: cabbage white butterfly
Patch enemy number one, particularly moving into the cooler months, is hands down the caterpillar of the cabbage white butterfly. Ironically, the pretty white butterflies flapping around your garden are often mistaken as allies, but they're the parents of green, camouflaged caterpillars that have a large appetite for ruining your crops.
The first preventive method is to erect netting to prevent them laying larvae. Without larvae in the big wide world of your patch, there will be no caterpillars, so fine netting is a sensible option - particularly when your plants are young, sweet and at their most vulnerable.
Another option is an opportunity to get crafty and make dummy butterflies. As the insect is territorial, and thankfully without great eyesight, setting up white butterfly-shaped plastic pieces attached to rigid wire confuses them into thinking other butterflies are already in the patch causing mischief. This is often enough to send them over the fence to bother your neighbour.
Illustrator Tom Bingham
  • Author: Mat Pember