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Cauliflower (Brassica oleracea var. botrytis) is a fantastic hybrid of wild cabbage (Brassica oleracea). There are several cauliflower varieties.
Purple Cauliflower, for instance, tastes like broccoli if harvested before frost and like Cauliflower if harvested after the frost date. Growing Cauliflower is challenging and requires gardeners to pay particular attention to bed preparation, pest management, and pre-harvest care.
- Cauliflower Plant Care Overview
- Soil Preparation to Grow Cauliflower
- Planting Cauliflower
- Watering Cauliflower Plants
- Controlling Cauliflower Weeds
- How to Harvest Cauliflower
- Managing Cauliflower Pests and Diseases
- FAQs on Grow the Best Cauliflower of Your Life
- In Closing
Cauliflower Plant Care Overview
Cauliflower Plants Groups
All vegetables can be categorized in three ways:
- Plant season
- Plant family
- The EPA management group
Cauliflower is part of the Brassicaceae family, and all the vegetables in the cole family are cool-season plants. Cauliflower is an excellent weather crop requiring consistently cool temperatures.
Regarding management approaches, specifically pest, disease, and weed management, Cauliflower is in EPA Group 5:Cole Crops and Brassica Leafy Greens, all needing similar methods.
The Brassicaceae family includes arugula, broccoli, Brussels sprouts, cabbage, Cauliflower, cress, horseradish, kale, kohlrabi, mustard, radish, rutabaga, and turnip.
Of these, broccoli, Brussels sprouts, cabbage, Cauliflower, kale, and kohlrabi are natural mutations of the Brassica oleracea.
The family is quite cold-resistant; some frost often improves the taste as starches are converted to sugars. This is especially true in Brussels sprouts and turnips,
Five Essentials Factors to Growing Cauliflower
To grow the best cauliflowers of your life, you need only remember five things:
- Soil preparation is as essential as sowing, growing and harvesting Cauliflower combined. Healthy soil builds plant resilience, can manage water availability better, and keeps nutrients readily available to plant roots.
- Cauliflower plants have specific temperature needs, both ambient and soil. When and where you plant them matters.
- While harvesting the best Cauliflower of your life means fabulous curds, growing them is only possible with good light and healthy leaves. A big cauliflower head of mostly curds cannot synthesize light.
- Disease and pest avoidance are much more manageable than managing established infestations or infections. Don’t give them a chance. Resilient, healthy plants don’t get sick. Insects are mainly drawn to weak plants.
- Keep the bed’s soil consistently moist but not wet. This is especially important for cauliflower seedlings and during the head formation season.
Soil Preparation to Grow Cauliflower
One of my favorite quips is, “You reap what you sow.” Sowing, in this sense, includes everything you do, long before a seed is planted, all the way to harvesting. So let’s start at the very beginning.
Preparing the Best Garden Bed for Growing Cauliflower
The bed you select for your cauliflower crop should be new to Brassica crops or, minimally, not have had any member-plants of the Brassicaceae family grown in it for at least three years — cole crops or brassica greens.
Cauliflowers are shallow-rooted and need a regular water supply to remain hydrated – not more water, just more often. Spread the inch to an inch and a half over the week, watering every second or third day.
It’s essential that the bed can keep the soil moist but not wet. For that to happen, it cannot be compacted or heavy clay. Adding compost to the bed helps introduce beneficial microorganism populations.
Add approximately four inches of compost to boost the soil’s carbon content, improving the cation exchange capacity (and nutrient bioavailability)
Soil pH and Fertility Needed for Growing Cauliflower
Soil tests should inform fertilizer applications. Cauliflower should be grown in fertile soil that drains well and has a pH between 6.0 and 7.0. A rich soil is required for successful cauliflower yields.
Depending on soil test results, phosphorus (P) and potassium (K) should be applied following soil test recommendations. A starter amount of NPK will help, as will two installments of side dressings.
You can use the following suggestions for a 40-square-foot planting site (3.6 m2). Please note that these are the active portions of NPK. Quantities are for a ten by-four-foot bed (3 x 1.2m)
Fertility Adjustment Before Planting
For a bed of medium Fertility, apply a week before planting. The applications should be worked into a depth of eight inches (20 cm)
Nitrogen: 0.88 oz./24.21 g of actual Nitrogen per bed
Phosphorous and Potassium: 1.47 oz./40.35 g per bed of each P and K
Side dressings of Nitrogen
Side dressing applications of Nitrogen should be given in weeks four and eight. Apply 0.59 oz./16.14 g of Nitrogen as the plant develops, the first application when the plant is about four inches tall.
It is only worthwhile to grow Cauliflower if the plant roots have access to water and nutrients consistently throughout the growing season.
Please note that this is in addition to a fall application of cured compost. The compost should be in the soil to stabilize it before fertilizer applications. The organic matter boosts the cation exchange capacity, helping your cauliflower crop better access available nutrients.
Fresh manure should not be used since it may contain hazardous microorganisms and exacerbate weed problems.
Depending on how much organic matter you use, you may not need to apply additional fertilizer if you use manure or compost.
Any fertilizer that contains a weed killer (“Weed and Feed”) may harm your veggie plants.
Starting Seeds Indoors
Start seeds indoors 4 to 6 weeks before the expected last early spring frost. Keep the soil around 75°F/23°C until germination and dropping it to around 60°F/15.5°C plants emerge.
You can do a spring planting if you know your garden temperatures will remain below 75°F/23°C, the temperature at which cauliflower bolt (go to seed).
Sow seeds half an inch deep in light soil or a quarter an inch deep in heavier soil (vermiculite vs. pumice). Cauliflower roots are shallow, so consider using peat pots for direct transplanting.
In about two weeks, the seeds should germinate. Once the seedlings emerge, turn on powerful grow lights above them.
Ensure seedlings get adequate sunlight or even supplemented artificial light (blue) for optimal resilience. Robust seedlings give your Cauliflower the best start to a healthy life.
Start fertilizing developing seedlings when the first genuine leaf grows. Once a week, use a half-strength starting solution. Apply fertilizer twice a week when the plant has two true leaves.
Remember to harden the plants off before transplanting, systematically exposing them to cooler temperatures. Do not harden them off by reducing watering—keep the soil moist consistently.
Transplant your seedlings when they’re about four to six weeks old and have about four to five true leaves.
For a fall harvest, plant cauliflower by sowing cauliflower seeds in situ in July. Fall crops must be timed, noting the first frost date to avoid heavy frost. Cauliflowers are the least hardy fall crop compared to other cole crops.
Plant the cauliflower seeds shallowly, about a fourth to a half inch deep, with three sources every 18 inches—you will cull the weaker ones based on emergence vigor.
Maintain consistent moisture in the soil during seed emergence. When the plants have emerged, thin them out so that only the strongest remain (about every 18 inches apart (45 cm)). Rows should be 36 inches apart (91cm).
Look after young plants, helping them to avoid heat, wind, drought, and insects. Keep the soil moist and cool, and use a floating row cover to keep pests out.
Watering Cauliflower Plants
At the risk of overstating it, cauliflower plants require enough soil moisture, and the plants must not be subjected to water stress if you want your cool-season crop to produce white, firm, and flavorful heads.
Plants with inconsistent rainfall or irrigation will have poor texture and may develop intense “off” flavors. Depending on your soil’s ability to retain moisture, water your 40-square-foot (3.6 m2) bed about 25 gallons a week (91 liters).
That is equal to an inch a week. During head formation in the growing season, you may need to up that to an inch-and-a-half (37 gallons/120 l).
Depending on your soil’s sand, you may need to water more than once a week, but the total should be about the same.
To determine how deep down the soil is damp, use a trowel. Keep the water going if it’s only an inch or two.
Controlling Cauliflower Weeds
Weeds should be killed before they become a nuisance by cutting them off or using a hoe or other implement or frequent, shallow tillage.
Hoe just deep enough to cut the weeds below the soil’s surface. When cultivating, take care not to harm the shallow-rooted cauliflower plants.
An organic mulch of up to four inches with weed-free straw or other organic material can help prevent weed development, buffer soil temperatures and reduce the need for frequent maintenance.
The cauliflower plant’s central green leaves stand tall and can be folded over the curd using a rubber band. This prevents sun scalding and produces a white cauliflower.
Once the cauliflower head is big enough, pull the outer leaves together and tie them. Without direct light, the curds can continue to develop in a “blanched” (or white) state.
The leaves of self-blanching types don’t need to be tied, and cauliflower of the Romanesco kind, or any color other than white Cauliflower, should not have its leaves tied.
How to Harvest Cauliflower
Cauliflower should be harvested when the cauliflower head has reached about six inches or more but before the flower heads open. Remove the leaves covering the head and cut the head off above ground.
Especially in spring plantings, curds will lose their firmness if left on the plant for too long. Harvest cauliflower before heavy frost as its intolerant of a freeze compared to other cole crops.
Stored in the fridge, Cauliflower will remain fresh for up to a week, and it has a three-week maximum shelf life, even when stored in a refrigerator with a damp towel.
Steam the florets before packaging and freezing them if you use Cauliflower as a rice replacement (carb-conscious diet). Once defrosted, you can shred them in a food processor for a base in several dishes.
Managing Cauliflower Pests and Diseases
Cauliflower leaves and stems are susceptible to damage from numerous environmental factors. The environment, plant diseases, insects, and wildlife can all impact the appearance and health of a plant.
A proper diagnosis is necessary before embarking on a management strategy.
Look for cabbage worms, flea beetles, root maggots, cabbage aphids, loopers, slugs and snails, cutworms, and swede midge.
Cabbage worms – Remove and destroy these by hand. As a preventative measure against early damage, row coverings may be used on small plantings. Install these when you plant cabbage and remove them before the summer heat becomes a threat.
Flea beetles – Use row covers to help protect plants from early damage. Install them at planting and remove them before temperatures get too hot in midsummer. Keep a handle on weed control to limit flea beetle populations. Sunflowers host them.
Cabbage root maggot – All cabbage family members are vulnerable to assault by white maggot larvae. The larvae burrow into plant roots and eat the roots. Plants that have been damaged will first show signs of withering and eventually die.
Cabbage aphids – A hard stream of water can be used to remove aphids from plants, but this should be done in the early morning to allow the leaves to dry in the midday sun. Wet leaves for extended times are strongly discouraged as they will enable several diseases to spread (by aphids).
Cabbage Loopers – These remain a threat throughout the plant’s life, and manage them the same way you do cabbage worms. A fine mesh floating row cover is essential as cauliflower plants don’t need pollinators.
Beneficial insects like lady beetles, lacewings, and parasitic wasps are natural enemies to aphids and other disease-spreading pests. Gray-brown or bloated parasitized aphids and the presence of alligator-like larvae belie their fact.
Preventing illnesses in Cauliflower often requires the same cultural measures. Leaf-related diseases can be prevented by using drip irrigation instead of overhead sprinkler systems. Adequate airflow also helps cauliflower plant leaves stay healthy.
Root-related diseases can be prevented by ensuring the soil drains well and has healthy soil biota—plant cauliflower in a raised bed to improve drainage and soil temperature management. Raised beds and mulch help keep the soil cool.
Seed-borne Cauliflower Diseases
- Black Leg caused by Phoma fungus
- Downy Mildew caused by Hyaloperonospora Oomycete
- Leaf Spot caused by Alternaria fungus
- White Rust caused by Albugo oomycete
- Yellows caused by Fusarium fungus
Cauliflower Leaf Diseases
- Bottom Rot caused by Rhizoctonia fungus
- Powdery Mildew caused by Erysiphe fungus (related to excessive nitrogen use)
Cauliflower Root Diseases
- Club Root caused by Plasmodiophora fungus
- White Mold (Timber Rot, Drop, Stem Rot) caused by Sclerotinia fungus
- Wire Stem caused by Rhizoctonia fungus
- Damping-Off Seed and Seedling Rots caused by several pathogens
FAQs on Grow the Best Cauliflower of Your Life
Now it’s up to you to grow Cauliflower you can be proud of. Indoor starter plants, moist soil, full sun, knowledge of the average first frost date, suppress weeds, and you’re off to harvesting this versatile vegetable in abundance. Good luck!
Of course, depending on where you live, you can do a mid-summer planting of this cool-season crop. Lucky you, and they’re in the top five of my favorite vegetables.
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