Growing Cauliflower

cauliflower starts | how to grow cauliflower

Growing cauliflower is a rewarding adventure in vegetable gardening. Cauliflower is a “biennial” crop – meaning that it is a flowering plant that takes two years to complete its life cycle. Cauliflower belongs to the family Brassicaceae, of the species Brassica oleracea, meaning it is a relative of broccoli, brussel sprouts, cabbage, collards, kale, and kohlrabi!

Cauliflower is known as the most temperamental member of the mustard family, as it is quite intolerant to warm temperatures and any changes in moisture. Despite these warnings, cauliflower is a delicious crop that will provide abundantly as long as its needs are met.

The French King, Louis the XIV – well-known for his extravagant demands – required cauliflower to be served at every feast! Though we can only speculate as to the reasoning behind this piece of history, we do know that cauliflower grown today still provides a generous portion of our necessary daily nutrients. One cup of cauliflower is high in cancer-fighting antioxidants and fiber, which aids digestion, and has more vitamin C than an orange!

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Start Growing Cauliflower

In the garden, a healthy cauliflower crop will produce a large, leafy, dark green plant. The leaves grow around the white flowers in the center of the plant. The florets remain bonded together in clumps called “curds” – until they “bolt”, or shoot to seed. It is common for this bonded clump of curds to grow to reach over two pounds. Globally, the majority of today’s cauliflower is grown in China and India; in the United States, California is the largest producer of cauliflower. Thankfully, with just a bit of practice and patience, you will be growing delicious cauliflower in your own backyard in no time.

When and Where You Should Grow Cauliflower

When choosing the perfect spot for your cauliflower crop, remember that this is an especially temperature- and moisture-sensitive vegetable. Cauliflower requires full sun for at least six hours each day. However, it must not get too hot. At the same time, extended periods of cold will also negatively affect the growth of the cauliflower curds. Aim for an area in your garden that will get at least six hours of full sun without reaching over 80 degrees (Fahrenheit) during the hottest times of the day. Cauliflower crops that are exposed to temperatures over 80 degrees Fahrenheit generally struggle with growth and have undesirable texture.

Due to its need to avoid the heat, cauliflower is a cool season crop. We recommend planting cauliflower in the fall. Avoid planting in the spring unless you are located in a region with reliably cool summers. If winter in your region consistently remains above 20 degrees, you can grow some varieties of cauliflower through winter for a spring harvest.

In addition to its precise temperature requirements, cauliflower plants, like nearly all vegetables, require soil with adequate drainage in order to prevent root rot. When planning your garden, be sure to pick an area that has good natural drainage, or build a “raised bed”. Cauliflower is one vegetable that will perform quite well in a raised bed, and you may find that the elevated bed better assists you in controlling the size of your crops, and quality of your soil.

Preparing a Bed

Prepare soil first with compost or manure and gently mix into the top layer only (roughly the uppermost six inches of soil). Cauliflower is a heavy feeder and requires a good amount of nitrogen. Adding a nitrogen-rich organic fertilizer at this point will benefit your cauliflower crop down the road.

Always test your soil’s pH prior to planting.

Some sources state that certain varieties of cauliflower can handle a slightly alkaline soil or a pH range between 0-7.5. We generally say it is always best to follow the directions that come with your seeds or transplants. According to The Old Farmer’s Almanac, one of the oldest and most authoritative guides on the subject of gardening, when referring to cauliflower, “The soil pH should be between 6.5 and 6.8.”

Growing from Seeds

Cauliflower seeds will take approximately between four and six weeks of growing indoors or in a nursery bed before they will be mature enough for transplantation into the garden. It is critical to keep the seeds moist and warm. You will want to keep them between 65-70 degrees (Fahrenheit) throughout this time. By doing so, you will encourage and ensure germination.

Starting Indoors

Seeds should be started indoors, in a seed-starting flat or individual biodegradable pots, in early summer (for Fall planting), or four to six weeks before the last expected “frost-free” date. Begin by planting the seeds approximately one-half of an inch deep in your seed-starting soil mix or peat pot. Make sure your rows are at least three to six inches apart. Thoroughly moisten your seeds at this point and remember to keep them moist throughout the growing process. Allowing soil to dry out is one of the primary causes of bitterness in mature cauliflower.

Once the cauliflower head reaches about three inches wide, wrap the innermost leaves over the top of the head, gather the rest of the leaves together and secure gently with a cord. Tying the tops of the plant’s leaves together in order to protect the inner, edible part of the vegetable is called “blanching”, which keeps the cauliflower heads from turning dark and bitter from the sunlight.

Direct Sowing Outdoors

Always plant cauliflower during your cool season, usually fall or late winter. If your winters typically stay above 20 degrees, you may grow cauliflower through the winter. If you have cooler springs, you may also plant during early spring. Ensure that your cauliflower is only in the soil when temperatures are below 80 degrees and above 20 degrees (Fahrenheit) for the best crop production.

Arrange cauliflower seeds 24 inches apart in a “chessboard” or X-style arrangement. Plant seeds approximately one-half of an inch into well-composted and moistened, loose soil. Place a net over seeds to prevent birds and other animals from eating emerging plants.

Growing from Starter Plants

Many gardeners recommend beginning cauliflower from a “starter plant”, available for purchase from many local growers and online retailers, as opposed to starting the plant from seed. For customers in the United States, pre-ordering plants online will ensure they are shipped to you at the proper planting time according to your USDA Climate Zone.

Avoid spacing starter plants, or transplants, too close together, as this will impede plant’s growth.

Transplanted seedlings should be placed 18 inches apart in rows. The rows should be spaced thirty inches apart. Do not place the seedlings any closer together as this will result in stunted growth.

Watering and Mulching

Cauliflower is a heavy feeder. Make sure the plant is getting adequate nutrition by topping off the soil with a nitrogen-rich fertilizer every two to three weeks only during the plant’s growing stages. Additionally, you could just apply your own homemade worm castings to the soil.

Use care when weeding around cauliflower plants, only picking weeds gently by hand when necessary. To prevent weeds, after first watering seeds or seedlings, cover the soil with a layer of organic mulch, such as grass clippings, which will help hold in the moisture. Mulch is highly beneficial to helping cauliflower maintain its delicate moisture balance.

After initially watering and mulching, growing cauliflower should only need approximately one inch of water each week. Remember to always water the plant at the roots, avoiding getting water on the leaves as much as possible. As with most plants, it is recommended to water earlier in the morning so that all water has time to be absorbed into the soil, and will not pool overnight. Always take care to prevent the leaves from wilting, as well.

Companion Planting for Cauliflower

Beans, celery, and onions are all good companion plants for cauliflower, but not all three can be planted together at the same time. Celery will pull a lot of moisture from the soil, but it also attracts many beneficial insects and leaves behind many nutrients. Beans and onions cannot be planted with one another. However, both cooperate quite well with celery and cauliflower. Beans and onions both attract beneficial insects and prevent the pests that destroy cauliflower crops.

Other vegetable plants that go well with cauliflower include beets, broccoli, brussels sprouts, chard, spinach, cucumber, corn, and radish. The strong scents of sage and thyme also make them compatible herbs to include in your cauliflower bed.

Dwarf Zinnias help to attract ladybugs and other predators, which protects the cauliflower from cabbage worms.

Peas are known to hinder the growth of cauliflower, so avoid planting these two crops in close proximity. Strawberries are known to attract slugs to the garden, so they are another plant to avoid making a neighbor. Finally, we do not recommend planting tomatoes with cauliflower because tomatoes are also heavy feeders, and this will reduce the amount of nutrition available for both plants.

Common Pest and Diseases

One of the most common pests in a cauliflower garden is the Cabbage Worm. Hatched from tiny eggs laid onto the leaves of the plant by the White Cabbage Butterfly, the cabbage worm eats the heads of cauliflower plants. Covers can provide a physical barrier which will prevent the butterflies from laying their eggs.

Another pest that feeds on cauliflower curds is the Cabbage Looper, one form of a moth. A different type of cabbage moth, the Diamondback Moth, likes to deposit its eggs on the underside of the cauliflower leaves, allowing newly hatched larvae to feed on the leaves virtually without restriction.

Cabbage root fly likes to lay eggs in the soil. Generally, gardeners will only notice when their plant collapses because the entire root system is infested with maggots. This is a very common problem in brassicas. The easiest solution is to create a barrier preventing the female fly from laying eggs. The barrier can be as simple as a piece of stiff cloth or sandpaper with an “X” cut into the center, positioned so that as the seedling pokes up through the soil, it will push through the material and have a built-in cover around the leaves and stem.

Additionally, you can use part of the cardboard insert from a paper towel, positioned around the plant stem in the same way. Crawling bugs will not attach their eggs to the fabric or paper, nor will they want to cross it. Combining these steps with an overhead row cover will provide adequate protection for your cauliflower – or any – growing vegetable crop.

One disease that often plagues cauliflower crops is known as Brown Head. The brown head is caused by allowing sunlight onto wet curd, which forms mildew. This inhibits the growth of the cauliflower head. Prevent brown head by keeping cauliflower heads dry, and out of the sunlight.

Harvesting and Storing Cauliflower

Cauliflower is typically ready for harvest within two weeks of blanching, however, check the crop frequently. Warmer weather could shorten this time, while cooler weather could increase it. Cauliflower should be harvested when the heads are approximately six inches in diameter to ensure that the plant does not go to seed.

When it is time to harvest your cauliflower, use a sharp blade to cut the mature head from the main stem. You will know the cauliflower is ready because the head will feel compact and firm. Length of time to harvest varies but is usually between 50 and 80 days after planting.

You will want to avoid allowing your cauliflower crop to “shoot to seed” or “bolt”, which happens when growing temperatures are overly warm. This will be obvious because the cauliflower curds will begin to separate, and eventually bloom upwards.

After harvesting your cauliflower, you can store the fresh florets in the refrigerator for several weeks – but make sure to get the vegetables into the refrigerator immediately. You can also choose to blanch and freeze the cleaned and chopped cauliflower florets for later use. After the crop has been harvested, you may pull and compost what remains of the plant, as it will no longer produce.

Saving Seeds

Cauliflower is a biennial crop. This means you will have to let it “go to seed”, or bloom, in order to retrieve seeds for harvest. It will take two growing seasons for the cauliflower to produce seeds. The first season that you plant your cauliflower, it will produce heads. When the head is left unpicked, the plant will then produce seeds the following year.

If you live in an area where your climate drops below freezing for several weeks, you will need to dig up your cauliflower during this time and store them in order to replant them the following spring to harvest seed. If you have mild winters – meaning the temperature does not drop below 28 degrees (Fahrenheit) for extended periods of time – your crop can remain in the garden, for seeds to be harvested in the spring.

If you want the best possible seeds, pick out at least six of your healthiest cauliflower plants to save for the task. More is even better. Cauliflower cannot self-pollinate, so the more flowers you provide for the bees, the greater the odds of sufficient pollination and quality seed production.

When cauliflower stalks are fully mature, they can reach over four feet tall. Seeds are located in pods along the stalk, ripening from the bottom up over the course of several weeks. Pods are ready for harvest when they turn brown and have a brittle texture. Cauliflower pods should not be harvested before they are ripe. Even though some pods break apart readily, harvesting the seeds from most pods can prove to be quite a challenge. Many experienced growers suggest placing the fully dried seed pods in a pillowcase and smashing with a hammer in order to break open. Once retrieved, the largest cauliflower seeds can be stored in a cool, dry location for up to three to five years. The viability of stored seeds should be tested before planting.

Best Variety for Your Climate

There are many types of cauliflower beyond the basic white variety we are most used to seeing in our grocery stores each week. Take a look below to discover the kind of cauliflower that sounds best for you!

Cauliflower varieties can be separated into two main categories.

“Early” types, including Snow Crown, and some green-headed varieties, mature around 70 days after planting.
“Main-Season” types – like Skywalker, Purple Cape or Violet of Sicily, as well as Orange Burst F1 varieties – require more than 80 days to mature, on average.

More specific types:

Aalsmeer is a cold hardy cauliflower; produces large curds. Predominantly grown in the UK.
All Year Round cauliflower can be grown from fall to spring (including winter in appropriate climates); ready for harvest in seventy days. Comparatively simple to cultivate.
Emeraude F1 cauliflower is a hybrid variety with green curds. It is ideal to harvest from late summer to fall.
Purple Cauliflower can refer to several different types of cauliflower, either heirloom or hybrid. The “Purple of Sicily” cauliflowers are naturally colored and of unknown origin. The vibrant purple color is not scientifically or genetically created. Purple cauliflower contains the same antioxidant found in red wine – anthocyanin. This is what causes the pigmentation.
Self-Blanching cauliflower leaves curl together to cover the head. This is a very popular type of cauliflower and is also known as a “Snowball” cauliflower.
Sunset F1 is one type of cauliflower that has orange curds; they are occasionally harvested early, can be enjoyed as a “baby vegetable”.

Additional Tips for Growing Cauliflower

Cauliflower seedlings do not like to have their roots disturbed. Avoid overhandling when transplanting seedlings, and bear this in mind when choosing how to start seeds. It is recommended to begin seeds in individual biodegradable pots or a peat tray for this reason.
Do not overfeed. Overfeeding often leads to many green leaves, but the cauliflower curds will not develop. This is referred to as “Buttoning”.
One concern with cauliflower seeds is cross-breeding. While cauliflower cannot self-pollinate, it can cross-breed with any other member of the brassica family. For this reason, take care when planning your garden design if you plan to harvest cauliflower seeds.