When to Plant Broccoli in the UK
The first thing to settle with broccoli is which kind you're growing, because the two most common types run on completely different timetables. Calabrese, the familiar green supermarket sort, is sown in spring and cut in late summer. Purple sprouting broccoli is sown in spring too, but then stands in the ground all winter and crops the following spring. Get the type and the sowing date right and the rest of the season follows on fairly easily.
Quick facts
Calabrese, sow: March to June, indoors from March or outdoors from April
Purple sprouting, sow: February to July, indoors from February or outdoors from April
Transplant: when plants are 10–15 cm tall
Spacing: 30–45 cm for calabrese, 60–80 cm for purple sprouting
Harvest: late summer to autumn for calabrese, roughly June through to the following March across all types
Which broccoli are you growing?
Calabrese produces one large central head with smaller side shoots afterwards. Sown in spring, harvested the same year in late summer and autumn.
Purple sprouting broccoli produces masses of slim purple spears rather than a single head. Sown in spring, it grows through summer and autumn, overwinters and crops from late winter into spring.
Both are brassicas and need the same sort of soil and protection, but their sowing dates and spacings differ, so check which one is on your seed packet.
When to sow calabrese
Calabrese is usually sown between March and June:
March to April, indoors: fill modular trays with peat-free seed compost and sow a pair of seeds per cell at about 2 cm deep, keeping only the stronger seedling.
April to June, outdoors: draw a drill roughly 2 cm deep. In a seedbed, space the seed about 7.5 cm along it; sowing where the plants will stay, put three seeds at 30 cm intervals and thin each group to the best one.
A few seeds at a time, repeated at intervals of two or three weeks, avoids the classic problem of a dozen heads all maturing in the same fortnight.
When to sow purple sprouting broccoli
Purple sprouting has a longer sowing window, from February through to July: indoors from February, or outdoors from April. Because it needs to be a substantial plant before winter, sowings from spring to early summer generally give the best results, and later sowings crop later the following year.
When to plant broccoli out
Whichever type you're growing, the plants themselves tell you when they're ready to move: transplant once they're 10–15 cm tall with a decent root system. For calabrese that usually falls between April and June, while purple sprouting can be planted out any time from mid-spring to late summer.
Plant them deeper than they were sitting in their pots, with the lowest leaves just at soil level, which helps them anchor firmly. Brassicas hate loose ground, so firm the soil around each one well.
Spacing is where the two types part company:
Calabrese: 30 cm apart, or 45 cm for larger varieties, with 45 cm between rows. Planting closer gives you smaller heads, which some people prefer.
Purple sprouting: 60–80 cm apart, with a similar gap between rows, as these plants get big.
Preparing the bed
Broccoli is hungry and wants fertile, well-drained soil that isn't acidic. Ideally, work in roughly two buckets of rotted manure or home-made compost to every square metre, doing it the autumn beforehand so the ground has time to settle. Calabrese does best at a soil pH of at least 6.8, and firm, limed soil also reduces the risk of clubroot.
If you're preparing the ground just before planting, tread it down with short shuffling steps and rake it smooth, so the plants go into firm ground rather than a fluffy bed.
Supporting tall plants
Purple sprouting broccoli grows to around 60–90 cm and stands through autumn gales and winter weather, so it usually needs support. Mound soil against the base of each stem and, where the site is exposed, drive in a stout cane and tie the main stem to it. A plant rocked loose by wind rarely crops well.
Protecting young plants
Every brassica is a magnet for pests, and young plants are the most vulnerable. Cover the bed with insect-proof mesh on canes or hoops, pinned down at the edges, from the moment you plant. That single step shuts out most of the usual culprits: pigeons, which will strip winter plants back to the ribs, along with cabbage white caterpillars, flea beetles, mealy aphids and the root fly whose maggots attack from below. Watch for slugs too, especially on young transplants.
Growing broccoli in containers
Broccoli can be grown in pots, though it needs a large, deep one and won't tolerate drying out. Calabrese suits containers better than purple sprouting, being smaller and quicker. See growing broccoli in containers
Planning the season
With staggered sowings across both types, broccoli can be harvested from around June right through to the following March. Calabrese fills late summer and autumn, and purple sprouting takes over from late winter, arriving in the hungry gap when there's little else to pick.
For sowing and care in detail, see how to grow broccoli in the UK. For picking, see when to harvest broccoli, and if plants aren't heading up, why broccoli doesn't form heads
Common questions
When should I plant broccoli in the UK?
Sow calabrese from March to June and purple sprouting from February to July, then plant out once seedlings reach 10–15 cm tall, usually between April and June.
Can I sow broccoli directly outdoors?
Yes, from April onwards, either in a seedbed or in its final position. Earlier sowings are better started indoors in modules.
How far apart should broccoli be planted?
Calabrese needs 30–45 cm between plants; purple sprouting needs 60–80 cm, as the plants grow much larger.
Is it too late to plant broccoli?
Purple sprouting can be sown as late as July for a crop the following spring. For calabrese, sowings after about June are unlikely to head up before the weather turns.
Sowing dates, spacings and soil preparation based on RHS guidance.