Summary of Cauliflower Growing Guide
Growing Cauliflower outdoors –if done, rationally, and on a scalable basis- can be a good source of income. In a few words, most commercial cauliflower growers start the crop from seeds (hybrids) in an indoor protected environment. As they wait for the young seedlings to grow and be ready for transplanting (usually 30 days), they prepare the field. They till the land, they remove any previous cultivation remains and weeds and integrate into the soil the basal fertilization combined with well-digested manure. They also design and place the drip irrigation system.
When they are ready for transplanting, they make small holes in the soil, where they plant the seedlings. Fertilization, Drip Irrigation, and Weed Management are applied in most cases. Most commercial cauliflower varieties can be harvested 60-150 days after transplanting. Time from Planting to Harvesting depends on the variety, climate conditions, and the age of the seedlings planted. Harvesting can be made through hand scissors or knives and is typically performed in multiple sessions. This happens because farmers often proceed to continuous planting in order to match continuous demand.
After harvesting, cauliflower growers plow and destroy the remains of the crop. They may also rotate the crop (with plants that do not belong in Brassicaceae family), to control diseases and prevent soil from depleting.
The restrictive factor when growing cauliflower is always the climate. The plant prefers mild temperatures to thrive and form flower-heads, which is our primary goal. It is susceptible to frost as it starts to have problems in low temperatures. Additionally, high temperatures also cause problems, especially to the heads, which begin to change their color or (even worse) bloom. As optimum temperatures, we consider those between 14 and 20°C (57-68℉); however, some varieties can tolerate up to 30°C (86 °F) for a short period.
First of all, it is crucial to decide the growing method, as well as Cauliflower varieties that thrive in your area. There are two methods to grow cauliflower: seeding directly into the field and seeding in a nursery and then transplanting.
How to Grow Cauliflower from Seed – How to produce cauliflower seedlings
Broadly speaking, professional farmers do not prefer to sow cauliflower seeds directly on the field for various reasons. First of all, cauliflower seeds are tiny, and seeding outdoors will lead to uneven sowing. Besides, when little cauliflower plants appear on the ground, they become most often a feed for snails and other soil pests. However, if you insist on sowing your cauliflower seeds directly outdoors, the most suitable period to do it is probably either in spring or in autumn. If you begin in spring, cauliflowers will be ready for harvesting during summer. If you start in autumn, they will be ready for harvesting during winter. All you have to do, after preparing the field, is to create rows at 70-80cm (27.5-31.5inches) distance one from another and dig holes at distances 20-40cm (7.9-15.7 inches) inside the row. Then, you can sow 3-4 seeds in every hole at 0.5-1.5 cm (0.2-0.6 inch) depth and gently cover with soil. You can irrigate immediately after sowing.
Cauliflower germinates best at 26 °C (80 °F) temperature on average. The seed needs to have optimum moisture levels to sprout. Over irrigation can be harmful. Some producers water every other day during this stage. Under optimum conditions, cauliflower seeds germinate in 8-10 days. After germination, you will most probably need to thin the plants. In case more than one seed has sprouted, you will have to remove all but the healthiest one from every sowing position. On average, you will need 1kg (2.2pounds) of seeds per hectare. Keep in mind that each grammar (0.034 oz.) of cauliflower seeds contains, on average, 270-320 cauliflower seeds.
Most commercial cauliflower growers start the crop from seeds (hybrids) in an indoor protected environment. Growers sow cauliflower seeds in seedbeds under controlled temperature at 20-30°C (68-86°F) and then transplant them into their final positions. They sow 2-3 seeds in every pot at 1cm (0.4inch) depth and gently cover with soil. They often use turf as a substrate for optimum aeration. It is crucial to maintain the substrate moist but not wet until the seed sprouts. Seeds will approximately germinate in 8-10 days, and the seedlings will be ready for transplanting after 30 days on average (3-5 weeks). By then, they will have developed 3-5 real leaves, and they will have an average height of 12 cm (4.7 inches).
Cauliflower Climate and Soil Requirements – Where to grow cauliflower.
Cauliflower is a cool-season vegetable. It can sometimes tolerate temperatures slightly below 4°C (39°F) without a problem. As preferable air temperatures for cauliflower farming, we consider those between 14 and 20°C (57-28°F). If the cauliflower plant experiences higher temperatures during its first growth stages, it will most probably start to perform intense stem growth and will delay the formation of the flower heads. At temperatures over 20°C (68°F), the plant starts to form leafy curds. This is something we have to avoid. Temperatures over 26 °C (78.8°F) will probably cause the heads to change color and bloom, decreasing their quality and commercial value. However, nowadays we have hybrid cauliflower varieties that are genetically programmed to tolerate temperatures up to 37°C (99°F).
Cauliflower can grow in a wide variety of soils. It grows best in slightly acidic soils (pH around 6.5). The plants have middle tolerance to high soil and water salinity levels. Although cauliflower plants love the sun, you should know that in most cases customers prefer white heads instead of slightly yellow ones. Thus, many farmers tie some outer leaves on the curds to prevent them from turning yellow.
Cauliflower Soil Preparation
The basic soil preparation starts a couple of weeks before transplanting the cauliflower seedlings. Farmers plow well at that time. Plowing improves soil aeration and drainage. At the same time, plowing removes rocks and other undesirable materials from the soil.
One week before planting, many farmers apply a pre-planting fertilizer, such as well-rotted manure or synthetic commercial slow-release fertilizer, always after consulting a local licensed agronomist. Many farmers integrate manure using tractors. The next day is probably the right time to install the drip irrigation system. Following the installation, some farmers can apply soil disinfection substances. They inject them through the irrigation system, in case soil analysis has revealed soil infection problems (ask a licensed agronomist in your area).
Cauliflower Planting and Plant Spacing – Cauliflower Plants per hectare
When it comes to planting cauliflower seedlings in the field, there are two main periods to choose from. The first period begins with planting during spring, so that cauliflowers will be ready for harvesting during summer. The second period includes planting in autumn and harvesting during winter.
In many cases, the most suitable period to plant cauliflower outdoors is during autumn. However, you should have in mind that in this case, the plants will need to come through vernalization to be able to form the heads. Farmers generally prefer plants aged from 3 to 5 weeks. At this point, they have developed 3-5 real leaves and have an average height of 12 cm (4.7 inches).
After all the preparation steps (plowing, basal fertilization, tillage, and installation of the irrigation system), we can proceed with transplanting. Growers label the exact points where they will place the young plants. They then dig holes and plant the seedlings. It is crucial to plant the seedlings at the same depth as they were in the nursery. Many growers prefer to plant cauliflower periodically every 2-3 weeks. They do so to be able to harvest cauliflowers periodically and thus cover the market demands.
Growers plant cauliflowers either in single or twin rows. For single rows, they keep 20-40cm (7.9-15.7 inches) distance between plants on the row and 40-90cm (15.7-35.4 inches) distance between rows. For twin rows, they keep 1m (39 inches) distance between one couple of rows from another and 30 cm (11.8 inches) between individuals in a couple of plants. Plants are placed again in distances of 20-40 cm (7.8-15.7 inches) on the rows.
In most cases, farmers plant 25000-45000 plants per hectare. (1 hectare = 2,47 acres = 10.000 square meters). There are cases in which the plant population of cauliflowers in a hectare can be 20.000 or 50.000 (overcrowded). The distances and the number of plants depend on the cauliflower variety, environmental conditions, and of course, the desired cauliflower size that is always dictated by the market.
Cauliflower Water Requirements and Irrigation Systems
Cauliflower can not generally tolerate drought; the quality of the final product will be significantly decreased under water-stressed conditions. Thus, most producers irrigate their plants regularly even during winter. On the other hand, excess water may cause root rot, which leads to the entire plant collapse, and significant yield losses. Cauliflower can collapse in 2-3 days under water-soaked conditions.
The most crucial periods when it comes to cauliflower irrigation is first during the first stage until the seeds sprout and secondly during the flowery head formation. Most producers irrigate their plants, providing frequent amounts of water every other day. They provide small amounts of water during the first stages and increase them periodically, as the plant grows. During summer, irrigation sessions may have to be increased to one every day.
Of course, water requirements can be different under different weather and soil conditions. For example, heavy clay soils usually need less irrigation than sandy soil. Different cauliflower varieties may also have different water requirements.
The most commonly used irrigation system in commercial cauliflower farming is drip irrigation.
Cauliflower Fertilization Requirements
First of all, you have to take into consideration the soil condition of your field through semiannual or annual soil testing before applying any fertilization method. No two fields are the same. Thus, no one can advise you on fertilization methods. You should take into account your soil’s test data, tissue analysis, and crop history of your field. However, we will list the most common fertilization schemes used by a considerable number of farmers.
Cauliflower plant demands heavy fertilization to thrive and produce a well-formed head. Thus, it is considered a hungry crop.
In fact, for the production of 20 tons per hectare, some farmers may need to add 120kg of N, 50kg of P2O5, and 200kg of K2O.
In many cases, producers start with basal fertilization. They integrate into the soil one-third of the total Nitrogen and the entire amount of K and P. They may also apply 25-40 tons of well-digested manure per hectare. Then, they continue by adding the rest of the Nitrogen divided into two applications. The first application takes place a week after transplanting and the second 1 month after the first one.
Some experienced farmers suggest a well-balanced slow release fertilizer, consisting of essential nutrients, such as Nitrogen (N), Phosphorus (P) and Potassium (K) (e.g. 20-20-20), in the form of granules. We can add the granular fertilizers directly to the soil surface and irrigate. The granules must not directly touch the young plants, because there is a risk of burning them.
However, most cauliflower farmers choose the method of fertigation (injection of water-soluble fertilizers inside the drip irrigation system). In this case, they can apply different rates of fertilizers for each day. Cauliflower’s growth is divided into three periods. The first period starts from transplanting (day 1) until day 45. During this period, they apply on average 1kg of N, 1 kg of P2O5 and 1 kg of K2O per hectare per day. The second period starts from day 46 and ends on day 70. During this period, they increase rates and they apply on average 3kg of N, 1,5 kg of P2O5 and 3 kg of K2O per hectare per day. The third period starts from day 71 and ends with the harvest. During this period, they apply on average 0,75kg of N and 1 kg of K2O per hectare per day.
However, these are just common patterns that should not be followed without doing your own research. Every field is different and has different needs. Checking the soil condition and pH is vital before applying any fertilization method. You can consult your local licensed agronomist.
Cauliflower Weed Management
An important growing technique in cauliflower farming is weed management. Cauliflower often suffers from weeds during the first stage of their growth. Weeds compete with young plants in terms of space, access to sunlight, water and nutrients. All cauliflower growers must have a sound weed control strategy. This may differ significantly between countries, law framework, the means of production, and the industry in which the product targets. Manual weed control every week is almost necessary in some cases (organic production). When the cauliflower has grown enough, weeds are not a major problem.
Cauliflower Harvesting – How and When to Collect Cauliflowers
The majority of cauliflowers are ready for harvesting 60-150 days after transplanting. However, harvest time mainly depends on their variety, as well as on environmental conditions. We can harvest cauliflowers by the time the heads have reached the suitable size of their variety. The heads should be compact and have a uniform color.
Harvest is done manually with scissors or knives during the evening. Otherwise, the sunlight may cause curd sunburns and foliage wilting. Producers cut the curds together with 3-4 inner leaves around them. Delayed harvest can significantly reduce quality, as there is a risk of heads to turn loose and yellow.
Cauliflower yields her hectare and acre.
A good yield would be 20-40 tons per hectare (17.851,2- 35.702,3 pounds per acre) or 25.000 curds. Keep in mind that 1 hectare = 2,47 acres = 10.000 square meters. The weight of each head depends on the variety and growing conditions. These yields can be achieved by experienced cauliflower farmers after years of experience. Cauliflower farming can indeed provide significant profits. In recent years, there is an increased demand for cauliflower in countries of Southern Europe and the Mediterranean region.
Cauliflower Physiological Anomalies – Common cauliflower problems
Cauliflower heads are sensitive to sunburns. The plant protects itself by covering the curds with inner foliage. However, some varieties lack this inner protective foliage, and producers take action, by covering heads with leaves of the outer foliage.
Cauliflower Pests and Diseases
Pieris, which is the most severe cauliflower enemy, is a white caterpillar that attacks cruciferous plants. The larvae of the parasite feed on foliage, causing significant quality reduction and great yield losses. Once the cultivation has been attacked, management is more complicated. Since pests develop immunity against pesticides easily, the best method to control them is through biological management. Pheromone traps are a commonly used technique. They attract male insects preventing them from fertile females. Thus, traps somehow reduce their population.
Predators are also being used.
Spodoptera exiqua is one of the most serious cauliflower pests. Larvae of the pest create holes on foliage to feed, causing the leaves to wilt and die. Once the crop has been attacked, management is more complicated. Since pests develop immunity against pesticides easily, the best method to control them is through biological management.
Downy mildew is a disease caused by the pathogen Hyaloperonospora parasitica. The infection is favored by moist conditions causing characteristic chlorotic spots on the upper foliage surface, combined with a downy mold on the underside. Heads are also infected as they form brown necrotic spots on them. The disease is dangerous as it leads to significant yield losses. Disease control begins with proper precautionary measures. These include weed control and proper distances between plants, adequate drainage, and avoidance of foliar irrigation. The general condition of the plants (nutrients and water level, sun exposure) can also boost their immunity. Chemical treatment is used only if the problem is severe and always under supervision from a local licensed agronomist. It is also crucial to use proper sanitation, such as tools disinfection every time we touch the plants.
Powdery mildew is a disease caused by the fungus Erysiphe cruciferarum and could turn very serious, as it leads to yield losses. Symptoms include chlorotic spots. Under optimum temperature and moisture conditions, a powdery layer resembling flour develops on the upper side of the foliage. Management includes the same methods used for downy mildew control.
Alternaria is a serious disease favored by increased soil moisture conditions. The fungus Alternaria brassicae causes the disease. The pathogen infects all parts of the plant above the soil. The most characteristic symptom of the disease is brown necrotic spots on the upper surface of the flower heads. Excess irrigation accelerates the disease cycle.