Cauliflower (Brassica oleracea var. botrytis) is extremely popular, not least because you can prepare its white flowers in a variety of ways. Here are tips on growing and caring for this healthy cabbage.
Origin of cauliflower
Cauliflower is descended from the original cabbage species Brassica oleracea var. silvestris and, like other cabbage species, belongs to the crucifers or cabbage family (Brassicaceae). Originally native to the Mediterranean region, it has been cultivated throughout Europe since the 16th century. Cauliflower is one of the most popular cabbage species, but is somewhat more demanding to grow than broccoli and other cabbages.
Appearance and growth
In cauliflower, elongated oval leaves grow from a firm stalk that rises only a short distance above the ground. At the edges they are slightly wavy. In their center is the inflorescence of closed, thickened flower buds. They are fused into a firm, yellowish-white head – the cauliflower head. This edible inflorescence forms in the first year of cultivation. In addition to minerals and trace elements, cauliflower contains vitamin C in particular. If you do not harvest the heads, the plant shoots and forms yellow flowers and seeds.
Location and soil
The demanding heavy feeder, cauliflower thrives best in loamy, deep, nutrient-rich soil that has good water-holding capacity. A high lime content is also important to reduce its susceptibility to clubroot. A pH of 6 to 7 is ideal, and cabbage also prefers a full sun to partial shade location.
Crop rotation and mixed cropping
In general, all cabbage species in the garden should not be grown again in the same bed for at least three to four years. If you want to sow a green manure before growing cabbage, never use mustard or oil radish, as these plants are also crucifers. Good mixed crop partners for cauliflower are peas, lettuce, leeks, celery and spinach. The latter is also an excellent gap filler, and is ready to harvest before the cabbage is large enough to cover the entire bed. Garlic and onions, on the other hand, should not be planted next to the cauliflower.
For growing cauliflower it is recommended to plant in spring and autumn, because in summer there is a greater susceptibility to pests. For early varieties, it is good to pre-grow the plantlets indoors. Sowing is carried out in seed trays already from the end of February, beginning of March, as the preculture takes about 30 to 45 days until the seedling is ready for planting. To do this, cover the seeds with two millimeters of soil. For germination, 18 °C (64 °F) is optimal, then place them in very bright conditions at 12 to 14 °C (54 to 57 °F). Prick out the plants after the formation of the first leaves in individual small pots or multi-pot plates. After about four to six weeks, the cauliflower seedlings will have reached a size suitable for planting out.
Work generous amounts of seaweed lime and compost into the soil as early as fall or about two weeks before planting. Then, when planting cauliflower, add an additional portion of lime directly into the planting hole. The planting distance is 50 x 50 centimeters (20 x 20 inches). Especially for early sowing until April, a film cover is advisable. Late varieties with sowing until June are planted in the bed with a spacing of 60 x 60 centimeters (24 x 24 inches).
Caring for cauliflower
Cauliflower has a very high water requirement. Too little water leads to poor leaf growth and small heads. Lack of water also promotes sprouting. After watering the seedlings that have been planted in the ground, you should initially reduce watering for two to three weeks. This will stimulate the growth of the root system. After that, a regular water supply is important for a good harvest. You should also hoe the vegetables regularly to reduce soil evaporation and loosen the soil. Since cauliflower is sensitive to injury, it is important to be careful when caring for it. A layer of mulch will provide even soil moisture in the summer. With most types of cabbage, it is also advisable to mound them a bit after they have grown. Cauliflower has a very high nutrient requirement. Therefore, fertilize the plants once or twice during the summer with horn meal. Alternatively, you can feed cauliflower weekly with diluted nettle manure or other organic vegetable fertilizer.
Since strong sunlight causes yellowing of cauliflower, the plant should be shaded. The older varieties are most prone to yellowing, as the foliage of most newer varieties surrounds the inflorescence. To shade, simply bend one or two large leaves inward and place them over the top. To keep the leaves in this position, you should connect both ends of the leaves with a toothpick.
Diseases and pests
Cauliflower, unfortunately, is not only popular with gardeners, but also with plant pests. One such pest that can cause major failures is the swede midge (Contarinia nasturtii). An infestation can be recognized by the fact that the young cabbage leaves grow twisted. Preventive measures include cultivation in wind-open locations and growing the young plants under fleece. Like other cabbage species, cauliflower is also attacked by the cabbage fly, whose maggots eat the roots. Here, preventive vegetable protection nets help. These have also proved effective against the caterpillars of the cabbage white butterfly, which are also among the most common cabbage pests. If clubroot, caused by a slime mold, occurs, you should observe a cultivation break of seven years. Infested plants must be immediately removed from the bed and disposed of in household waste.
Harvesting and using cauliflower
Depending on the time of planting, cauliflower can be harvested from June to October, approximately eight to twelve weeks after planting. The vegetable is ripe as soon as the cabbage head has reached the desired size and is firm to the touch. When harvesting, cut off the entire stalk with the inflorescence. Cauliflower is most often steamed or boiled, but can also be roasted or baked. Although the vegetable can also be eaten raw, the white florets are then difficult to digest. Homemade cauliflower rice, a low-carb alternative to conventional rice, or grilled cauliflower are also trendy. Cauliflower will keep for a few days in the refrigerator after harvest. If you want to store cauliflower, do not cut the entire plant, but pull it out of the ground, root and all. Remove the lowest leaves and hang the cauliflower upside down in a cool and humid cellar. It can be stored in this way for about four weeks. It will keep for up to twelve months if you freeze the cauliflower.
A special feature are the so-called winter cauliflower varieties. They tolerate frosts down to -12 °C (10 °F ) – so they can stay on the bed through the winter and are ready for harvesting from April. However, cultivation is only recommended in mild regions. Recommended winter cauliflower varieties are ‘Selection Z’ and the purple variety ‘Purple Cape’.