How To Grow Cauliflower For A Successful Harvest


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Are you wondering how to grow cauliflower in your vegetable garden?

Start the plants by seed indoors 10 weeks before your last frost date then plant them outside in the early spring while the weather is still cool. Water and fertilizer regularly until the button head starts to form and then blanch until ready to harvest.

Cauliflower is known to be one of the harder plants in the brassica family to grow. But if you enjoy eating it then it’s well worth trying.

I struggled for years to grow good cauliflower in my garden but through a lot of trial and error finally learned how to grow tasty cauliflower.

If you know what cauliflower likes it becomes much easier to grow.

How To Grow Cauliflower text overlaid on a close up photo of fresh cauliflower

When Should You Plant Cauliflower?

Cauliflower is a cool-season vegetable and it’s really important to remember than when you are planning your garden.

Cauliflower will thrive in temperatures from 60 to 75 F (16-25 C) but when the weather warms above that cauliflower starts to bolt.

Temperatures over 75 F (25 C) will often cause the plants to bolt (go to seed) or button (grow multiple tiny heads).

Because of this, it’s best to plant cauliflower in the early spring so they can produce heads to harvest before the summer heat arrives.

If you want to grow cauliflower in your fall garden look for varieties that can withstand the summer heat at planting time, or grow in part shade.

Planting

White cauliflower ready to harvest
White cauliflower ready to harvest.

Start cauliflower from seed indoors 10 weeks before your last frost date in the spring by planting seeds 1/4 inch (6.35 mm) deep in your seed trays.

Keep the seedlings under grow lights or in a bright sunny window. Making sure the location is out of drafts and stays about 60 F (16 C).

Grow the seedlings indoors for 4 to 5 weeks and then harden them off to plant in your garden undercover to protect them from hard frosts.

If you can’t provide frost protection then delay transplanting until 2 to 3 weeks before your last frost date.

You don’t want to wait too long and have plants that are very mature going into the garden. It can cause them to form small button heads.

At this time of year, it’s still a good idea to cover the plants with a floating row cover or a cold frame to protect the seedlings from the worst weather.

Cauliflower is cold tolerant but it is more sensitive than cabbage or kale. So taking a little time to protect the seedlings early in the season can help you get a good crop later on.

Space the seedlings on 18 to 24 inch (45.72 to 60.96 cm) centers when you plant them into the garden.

Growing

Cauliflower plant fully grown
Homegrown cauliflower

Fertilizing

Before planting cauliflower prepare the planting bed with 1 to 2 inches (2.54 to 5.08 cm) of good quality compost. This helps to provide nutrients and organic matter that also retains moisture in the soil.

When planting the seedling out fill the planting hole with liquid fertilizer, I like to use fish emulsion. Then place the seedling inside and backfill with soil.

A month after planting feed the cauliflower plants again with liquid fish fertilizer.

Watering

It’s important when growing cauliflower that you water it often, don’t let it dry out. If you haven’t had enough rain make sure to water it with an inch (2.54 cm) of water every week.

It’s always better to water deeply once a week. This will help the plants grow quickly and develop deep roots so they don’t get slowed down in dry patches.

Mulching with shredded leaves, wood chips, or straw will also help to keep the moisture level in the soil even and suppress weeds at the same time.

Blanching

White varieties of cauliflower need to be blanched, while pure, orange, and green types should never be blanched while they are growing. It would cause them to lose their pretty colors.

When you start to see small 2 inch (5.08 cm) heads forming inside the plants it’s time to start blanching them.

This only needs to be done if you are growing a white variety of cauliflower.

Take some of the large outer leaves and bring them together over the top of the plant. Then tie them together with a rubber band.

Check a few times a week to make sure the leaves are still covering well and adjust if necessary.

This will help to protect the growing cauliflower from the sun giving you a pretty bright white curd.

Harvesting

Fresh picked cauliflower
Fresh picked cauliflower

You can harvest cauliflower when the heads have reached 6 to 8 inches (15.24 to 20.32 cm) wide. Use the head size and days to maturity from your seed package as a guideline.

But don’t wait too long, you want the heads to still be tight and firm.

About 7 to 12 days after you start the blanching process works well for white varieties.

Cut the head off the plant, after that you can pull the plant out of the garden and compost it.

Unlike its cousin broccoli, it will not make any more shoots that you can harvest. So there is no point in leaving the plant in the garden longer to take up space.

Pests

Cauliflower is vulnerable to the same pests that other plants in the cruciferous family are.

Growing Time
60 days

Total Time
60 days

Difficulty
Intermediate

Materials

  • Cauliflower seeds or seedlings
  • Fish emulsion fertilizer
  • Row cover

Instructions

  1. Start cauliflower indoors by seed 10 weeks before your last frost date. Plant the seeds 1/4 inch (6.35 mm) deep in your seed starting mix.
  2. Make sure to give the seedlings lots of light under your grow lights or in a bright sunny window.
  3. Transplant the seedlings into your garden 4 to 5 weeks before your last frost date. Spacing the plants 18 to 24 inches (45.72 to 60.96 cm) apart. Make sure to provide them with protection from cold weather and frosts.
  4. Cauliflower is a heavy feeder, make sure to plant it into rich fertile soil that’s been amended with compost.
  5. At the time of planting fill the hole with liquid fertilizer before placing the seedling inside. Fertilize the plants again 1 month after planting with liquid fish emulsion or your favourite garden fertilizer.
  6. Water your plants consistently providing 1 inch (2.54 cm) of water each week if you haven’t had enough rainfall. Mulch around the plants to help keep the soil moist and suppress weeds.
  7. When you start to see small 2 inch (5.08 cm) cauliflower heads forming it’s time to blanch them (white varieties only). Take a few of the large outer leaves and tie them together over the top of the plant.
  8. Harvest cauliflower when the heads are 6 to 8 inches (15.24 to 20.32 cm) wide or according to your seed package information. This will be about 7 to 12 days after you start the blanching process. Cut the head off the plant leaving a few inches of stem attached.

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