Cauliflowers are quite sensitive when it comes to growing conditions and temperature fluctuations, meaning that many find it a difficult vegetable to grow. However, get things right and you’ll be able to experience the immense satisfaction of harvesting perfectly-formed cauliflower heads in a spectacular array of shapes and colours.
Growing Cauliflowers: A Quick Snapshot
When to Sow – Feb-May
When to Plant – Mar-Jun
When to Harvest – Jun-Aug
Average Yield per Plant – 600g
Spacing – 60cm
Depth – 1-2cm
How to Grow Cauliflowers at Home
There are three main types of cauliflower out there:
- Spring cauliflower
- Summer cauliflower
- Winter cauliflower
Most winter cauliflower varieties are actually more of a type of heading broccoli. This means that they’re a little easier to grow, but don’t taste quite the same as a true cauliflower. If true cauliflower is what you’re after, then spring and summer is the best time of year to grow your own at home.
Cauliflower Temperature Requirements
Cauliflowers do best in temperatures between 16-18°C. It needs these temperatures to be as consistent as possible, which is where many gardeners struggle. This is why it’s crucial to get your timing right when growing cauliflower at home, taking your local climate into account.
Cauliflower Light Requirements
Although they require cool temperatures, cauliflowers also need full sun (we told you they were tricky!). That being said, partial shade during the hotter months of the year can be beneficial – too much direct sun could cause your cauliflowers to bolt.
Cauliflower Soil Requirements
In order to thrive, cauliflower needs a rich and fertile soil. Adding a few centimetres of compost over the top of poor soil won’t do – cauliflowers need this richness to run deep.
If possible, try to prepare your cauliflower planting bed the season before. Mix in plenty of quality compost and well-rotted animal manure, giving it the winter to settle into the soil.
How to Grow Cauliflowers from Seed
Cauliflower seeds can be started indoors in late winter, or direct sown outside. While direct sowing may be the least labour intensive of the two methods, starting your seeds off indoors will give you better germination rates and healthier plants overall.
Cauliflower seeds should be started about four to six weeks before your last frost date.
Young cauliflower plants hate having their roots disturbed, so always start cauliflower seeds in modules or small pots, rather than single trays.
How to Sow Cauliflower Seeds
- Fill your modules/pots with a quality compost
- Water the modules well, making sure that the water is draining freely from the bottom of each one
- Make an indentation in the centre of each module, about 1.5cm deep
- Place two cauliflower seeds into each indentation and then cover them back over
- Lightly water your modules again
Surprisingly, cauliflowers germinate best at temperatures of around 27°C. However, that’s not attainable for many in the winter months, so try to aim for a temperature between 21-27°C instead. Remember – keeping temperatures consistent is the most important thing.
That being said, heat isn’t essential for germination. Place your modules into a cold frame or an unheated greenhouse and the seeds will still germinate, although this will take a little longer than if they were given heat.
How to Look After Cauliflower Seedlings
It will take anywhere between 8-14 days for your cauliflower seeds to germinate. Once they do, you’ll need to make sure that your seedlings are receiving plenty of bright light.
Growing them by a window could turn them leggy, which will weaken your plants. To prevent this, make sure that you keep rotating the trays that they are growing in to give all parts of each plant even light exposure.
Water is extremely important for cauliflower seedlings. Keep them consistently moist, making sure that they never dry out.
Once your seedlings are about a week old, you’ll need to thin out the weaker seedling from each pot. Don’t try to pull them out and replant them, as this will only disturb the roots of the seedling left behind. Instead, use some sharp scissors to snip the weaker seedling at its base. You can always use your thinnings in a salad or as a garnish – cauliflower microgreens are packed with nutrients!
Depending on the size of pot you started with, you may need to pot up your seedlings before they move outside. Regularly check to see if roots start to emerge from the drainage holes at the bottom of your pots. Although cauliflowers don’t like to be disturbed, allowing them to become root-bound would be even more detrimental.
How to Plant Cauliflowers Outside
You’ll know that your cauliflower plants are ready to move out once they’ve grown a few sets of true leaves. This usually takes about a month.
However, before planting your cauliflowers outside, you’ll need to harden them off. This involves placing your modules outside for an hour on the first day, before slowly increasing this each day until your plants have spent all day and all night outside.
At this point, create holes in your planting bed that are 60cm apart. This may seem like a lot, but the more space you give to each plant, the larger each cauliflower head will be.
Make sure that your planting holes are deep enough to accommodate the entire root ball of each plant.
Then, place your cauliflower plants into their new homes before covering back over with soil. Firmly push the soil down around each plant – you want the roots to have good contact with the soil.
Once you’re done, give your plants some water.
How to Plant Cauliflowers in a Greenhouse
Due to the fact that cauliflower is a cool-season crop, greenhouse temperatures are often too high for it, resulting in the plants bolting early.
Winter cauliflowers will often do well in a greenhouse, but summer varieties should always be planted outside. That being said, an unheated greenhouse is a great place to start cauliflower seeds and to grow on seedlings before transplanting them outside.
If you would still like to try growing cauliflowers to maturity in a greenhouse, follow the planting steps above. Alternatively, if you need to plant in containers, make sure that these are large enough. 30cm for both width and depth is the minimum size you should aim for.
How to Care for Cauliflowers
Cauliflowers do require more care than the average vegetable, but the attention you bestow on them during the growing process will be more than worth it come harvest time.
Cauliflowers need to be kept consistently moist. They require about 2.5-3cm of water a week. If rainfall isn’t providing this, then manual watering is a must.
Never allow the soil that your cauliflowers are growing in to run dry. If this happens, the curds on your cauliflower heads won’t form tightly, giving them an odd texture.
Cauliflowers take a long time to mature, meaning that soil nutrients will likely run out well before your cauliflowers are ready to be picked. In order to ensure that your plants receive all of the nutrition they need to thrive, you’ll need to regularly feed your cauliflowers.
Go for an organic general-purpose fertiliser, such as a liquid seaweed concentrate, applying this to the soil around your cauliflowers every two to four weeks.
Don’t be tempted to over-dilute – cauliflower roots are very tender and can easily burn when exposed to too much fertiliser.
You need to keep your cauliflower plants weed-free – they don’t do well with competition.
However, frequently weeding around your plants can end up being damaging too. The constant activity disturbs cauliflower roots, causing the plant stress.
Ideally, keep your cauliflowers as weed-free as possible from the start. The best way to do this is by applying a mulch – this will suppress weed growth around your plants.
Managing Sun and Temperature
Too much sun and heat early on in the season can spell disaster for cauliflower plants.
To save your plants from bolting early, set up some shade cloth around your cauliflowers if an unexpected hot spell arises.
Blanching Cauliflower Plants
About a month after you’ve planted your cauliflower out, start checking them to see if curds are developing.
Once the head is about the size of an egg, bring the outer leaves over the top of the head and gently tie them in place. This process is known as blanching, and it protects the head from the sun.
Blanching isn’t necessary, but un-blanched heads will often turn green or brown as they grow, which can then affect their flavour.
How to Harvest Cauliflowers
Cauliflowers take between two to three months to mature. It’s a good idea to check your seed packet to find out the average amount of time the variety you’re growing takes to mature, because it isn’t always easy to work out when a cauliflower is ready to be picked.
Once harvest time approaches, keep an eye out for cauliflowers that have grown an adequately-sized head with dense, tight buds.
A cauliflower that’s harvested too early can still be used in the kitchen, but one that’s left too long will end up flowering. This leaves the cauliflower tasteless and lacking in texture.
To harvest a cauliflower, simply use a sharp knife to cut the main stem. Try to leave a few of the outer leaves intact – they’ll help to protect the head.
Although the rest of the plant that’s left behind in the ground won’t produce any more heads, cauliflower leaves are still a delicious ingredient to cook with. If you plan on harvesting the leaves, make sure that the stem left in the ground is as long as possible.
How to Store Cauliflowers
If you have a large harvest, then the easiest way to store your cauliflowers is by hanging upside down in a cool and relatively dark place. Garage rafters would be ideal – tie some string around each stem and leave them to hang. Misting them each day will prolong shelf life, which is usually about one month.
If you’re only harvesting a few heads at a time and have some extra room in your fridge, your cauliflowers will keep for a couple of weeks. Wrap each head in a damp paper towel and then place them into a perforated plastic bag. Don’t trim the leaves off – these will keep the heads fresher for longer.
Your best option for long-term storage would be freezing. Cut the heads up into large chunks, before blanching and freezing. They will last for about one year.
How to Prepare & Cook Cauliflowers
Start by cutting off any outer leaves on your cauliflower.
Preparation methods after this will depend on how you want to cook it. If florets are what you need, quarter the head, cut out the central stem, and then cut into florets. Alternatively, cut a cauliflower lengthwise and slice it into large steaks, or leave baby cauliflowers whole.
Fresh cauliflower has a deliciously nutty and sweet taste. Some of the best ways to bring out its unique flavour are:
- Roasted cauliflower steaks
- Grilled cauliflower wedges
- Cauliflower cheese
- Steamed and topped with butter
- Roasted whole and carved
Common Cauliflower Problems
Pests and diseases are unfortunately a common occurrence when growing cauliflower at home. There are a variety that you could end up dealing with, but some of the most common are:
- Cabbage moths – one of the most destructive cauliflower pests, these green caterpillars hide on the underside of leaves, slowly eating the plant until there’s nothing left. Neem oil can sometimes help, while attracting predatory insects, such as the parasitic wasp, is a good long-term plan.
- Cabbage root fly – the maggots that hatch from the eggs of these small flies burrow into the soil and destroy cauliflower roots. Netting your plants or giving each one a cabbage collar can help to prevent this.
- Clubroot – a disease that leads to stunted growth and wilting, purple leaves. Remove infected plants as quickly as possible and avoid growing brassicas in that soil again, unless they are clubroot-resistant varieties.
Popular Cauliflower Varieties to Grow
In addition to offering a huge choice of different shapes, sizes, and flavours, each cauliflower variety will also vary in terms of how long the plants take to mature. This could be anywhere between 55 to 100 days.
While you may be tempted to pick a variety based solely on its appearance or culinary appeal, don’t forget to also keep the length of your growing season in mind.
Here are some of the most popular cauliflower varieties to grow at home:
- Clapton – a clubroot-resistant variety that produces large white heads
- Cheddar – produces vividly-coloured yellow/orange heads that are especially high in beta-carotene
- Purple Graffiti – grown more for its colour than its flavour, although it is also packed with antioxidants
- Igloo – often grown as a mini cauliflower
- Green Macerata – an Italian variety with apple-green heads
- Rober – known for being highly adaptable and productive
Although they can be a little challenging to grow, cauliflowers are also one of the most satisfying brassicas to harvest. Give your plants some extra love and attention over the growing season and you’ll be rewarded with a harvest that far exceeds the flavour and texture of a store-bought cauliflower.