Why your cauliflower isn't forming a head

August 9, 2025

Cauliflower has a bit of a reputation as the fussy one in the brassica family, and it's earned it, because it'll happily grow a big healthy plant full of leaves and then either never make a head at all or make a tiny one the size of a golf ball, and it's almost always telling you something about when it went in or how it was treated along the way.

It hasn't had long enough

The first thing to check is the calendar, because cauliflower is slow and a lot of varieties take several months from planting before a head starts to show. The seed packet or seedling tag will give you the days to maturity, and if you're not there yet the plant may simply not be ready.

It went in at the wrong time

Cauliflower wants to grow its leaves in the mild weather of autumn and then form its head in the cool, so around here seedlings want to go in from about February through to April. Planted too late, it sits in cold soil through winter and stalls, and planted out in the heat it tends to rush, so either way you can end up with leaves and not much else.

It got stressed

A tiny early head, which growers call buttoning, is the classic sign of a stressed plant, and the usual culprits are a seedling that was root bound in its punnet, a dry spell, a hungry bed or a check in growth from transplant shock. The best defence is to plant young seedlings that haven't filled their punnet and water them in well. After that, keep the soil evenly damp.

It's hungry

Cauliflower is a heavy feeder, so a bed that's had nothing dug into it struggles. Dig plenty of compost and a complete fertiliser through the bed before planting, and give them a feed as they grow. Lots of nitrogen and nothing else can give you a lush plant that's all leaf, so a balanced feed is better than straight nitrogen.

What you can still do

If the plant is healthy and it's still the cool part of the year, keep the water steady and give it a balanced feed, because a few more weeks may be all it needs. If it's already warming up and there's still no head, it probably won't make one, and the leaves are perfectly good to eat, so I'd pick them and get the bed ready for the next crop.

Keeping the head white

Once a small head does appear, folding a couple of the big outer leaves over it and tucking them in shades it from the sun, which keeps it white and tender. That's only about colour, it won't make a head form, so don't bother doing it until there's actually something there to cover.

Shop related products

Brunnings Seed Raising Mix 5L. For raising your own seedlings so they go in young.
Brunnings Blood & Bone Based Fertiliser 5kg. Dug through the bed before planting.
Seamungus 500g. A pelletised seaweed and manure feed while they grow.
Manutec Soil pH Test Kit. Brassicas don't like acid soil, so it's worth knowing what yours is.

Did you know we also stock Snowball cauliflower seed in the shop, and it isn't on the website, so give us a ring on (08) 8536 4333 to check what's on the shelf.

Everything else for the veggie patch is in our garden centre, and if you bring a photo of the plant in we'll have a look at it with you.

More on the veggie patch

Cauliflower is the vegetable I treat with the most patience and the least confidence, which feels about right for something that keeps you guessing until the very end.

Candeece