by Cauliflower is a rather capricious crop. Even if we have selected a productive variety and looked after the plants all summer, we may be disappointed at the end of the season when we see unsightly blackening inflorescences. The main reasons for a poor harvest are diseases and lack of nutrition.
Although cabbage grows well in well-lit areas, heat and bright sun can also negatively affect the harvest. If the inflorescences have almost formed, they must be shaded in sunny weather so that they do not darken.
It is very easy to protect cauliflower heads from the sun: tie the larger leaves at the top with a rubber band or break 1-2 leaves to make a kind of “umbrella” over the inflorescence. However, it is worth remembering that you cannot leave the formed inflorescences in the garden for a long time – they quickly overripen and often suffer from diseases that can destroy the plantings.
Diseases of cauliflower
Bacterial spot affects all types of cabbage, including cauliflower. Angular, slightly sunken dark brown or black spots with an oily tint and a translucent border appear on the leaves. In severely affected plants, the leaves usually turn yellow, dry up and fall off. Longitudinal black spots can be seen on the stems, leaf petioles and flowers. Dark brown spots appear on the affected cauliflower heads, which quickly spread in high humidity.
Mucous bacteriosis, or wet bacterial rot, can affect cauliflower throughout the entire growing season. When affected at an early stage, plant development is delayed, heads do not form, and the stem rots. When the inflorescences have already formed, small brown spots first appear on them. At first, the rotten areas are located superficially, but with high humidity, they quickly cover the entire inflorescence. On cabbage leaves, bacteriosis appears as small watery black spots.
The spread of bacterioses is facilitated by insects, wind, and any mechanical damage. Even a lack of microelements significantly reduces the immunity of plants and they get sick more often.
When the first signs of bacterial diseases are detected, the affected plants should be dug up. If there are very few spots on the heads, they can be cut off, and the healthy part of the inflorescence can be eaten or frozen for long-term storage. But such heads cannot be put into the cellar, since the rot will spread quickly.
Microorganisms that cause bacterial diseases are preserved in the soil on plant residues. Therefore, after harvesting the affected plants, it is necessary to collect all the leaves and stalks, and then treat the soil and the cabbage remaining in the garden with a biopreparation based on hay bacillus or trichoderma (Alirin-B, Gamair, Fitosporin-M, Sporobacterin, Trichoplant, etc.).
Nutritional deficiencies
Cauliflower is very demanding of soil fertility, responds to fertilizing with organic and complex mineral fertilizers during the summer. If you do not pay enough attention to preparing the bed for growing this crop, then we are unlikely to get dense beautiful inflorescences.
The best place to plant cabbage is a plot where vegetables were grown last year, for which organic and mineral fertilizers and wood ash were added. It is good to plant cauliflower after cucumbers, zucchini, onions, garlic, tomatoes, and carrots. Cabbage is returned to its previous place no earlier than after 4-5 years, so that pathogens do not accumulate in the soil, which causes a sharp drop in the harvest.
When growing cauliflower, special attention should be paid to the acidity of the soil – cabbage prefers neutral or slightly alkaline soil (pH 6,5-7,2). More acidic soil should be limed, dolomite flour, chalk, ash should be added – otherwise, the risk of cauliflower being affected by clubroot increases, which most often develops on acidic soils.
However, after applying lime fertilizers, some microelements, in particular boron, become unavailable to plants. And if the heads of cauliflower are formed loose, with dark spots, this may indicate that the plants lack boron.
Foliar feeding with a 0,05% solution of boric acid (5 g per 10 l of water) or a complex fertilizer with a high concentration of boron in organomineral form (for example, KompleMet Bor) can help. Spraying with boric acid is best done in the evening, after the end of the flight of pollinating insects.
In addition, cauliflower sometimes suffers from a lack of phosphorus, which is also responsible for the formation of dense inflorescences. Therefore, if potassium-phosphorus fertilizers were not added to the soil during the preparation of the bed, then during the growing season you can feed the crop with an aqueous solution of potassium monophosphate (10 g per 10 l of water), as well as a complex mineral fertilizer with an increased phosphorus content: Kristalon Yellow, Agromaster 13.40.13, etc.
Proper preparation of the bed and compliance with crop rotation rules will help prevent an imbalance of nutrients. Be sure to add organic fertilizers to the area where you plan to plant cabbage: mature compost, vermicompost or humus (5-7 kg per 1 sq.m). Organic fertilizers not only provide plants with all the necessary nutrients, but also improve the soil structure, increase its microbiological activity and fertility.
To get a good harvest of dense and beautiful heads of cauliflower, you need to follow simple rules of agricultural technology: add organic and mineral fertilizers to the bed, protect plants from diseases and pests, water the plantings regularly and cut off the inflorescences in time. And if you do everything correctly, then healthy and tasty cauliflower will definitely please you with a good harvest.
