My cabbage isn't forming heads. Why? What should I do?

Growing cabbage is generally not difficult, but sometimes problems arise when white cabbage fails to form a head or produces multiple defective florets. By identifying the causes of this problem early, the situation can be corrected fairly quickly.

Reasons

There are several reasons why cabbage heads fail to form when grown outdoors. The following factors can lead to yield loss.

Poor quality seeds and seedlings

Seeds should only be purchased from specialized retailers or trusted sellers. Even the most attractive packaging is no guarantee of a quality product. Unscrupulous sellers may sell seeds harvested from cabbage hybrids or crossed with wild rapeseed. Such seeds will never produce quality heads.

This factor also applies to the purchase of young seedlings. Such seedlings are grown by unscrupulous greenhouse growers for sale.

Insufficient lighting

Being a shade-intolerant crop requiring 15-16 hours of sunlight, cabbage fails to form a head even when grown in partial shade. If planted in shade, partial shade, or densely packed conditions, the plant will expend all its energy stretching toward the light, failing to form a head. In densely packed conditions, cabbage should be spaced 50 x 60 cm apart.

Tall crops growing near the vegetable, blocking sunlight for part of the day, will also contribute to the failure of the head to form. Tall plants should only be planted on the north side of the vegetable, at least 70 cm away.

Insufficient or excessive soil moisture

If the soil lacks moisture, the plant cannot develop normally and form a high-quality head of cabbage. However, if the soil is oversaturated with moisture, the cabbage begins to absorb nitrogen more actively. This element promotes vegetative growth at the expense of head formation.

Lack of trace elements and potassium

Cabbage is a vegetable that requires phosphorus, potassium, and micronutrients. Without these chemicals in the soil, the head will not form. However, it's important not to overfeed the crop, as this can cause chemical burns to the vegetative mass, which will inhibit head formation. The vegetable is particularly dependent on potassium, which is essential for root development and head formation.

Pathogens and insect pests

Pathogens and sucking pests, if not controlled promptly, weaken the crop. As a result, the plant cannot develop vigorously and does not form a head.

Signs that a head of cabbage will not form

When growing cabbage in their garden, an experienced gardener will immediately identify a plant that is unable to form a head by the following characteristics:

• a weakened, wilted plant is susceptible to attack by pathogens or a lack of microelements;
• a vegetable with good leaf apparatus does not form a head of cabbage - a sign of a lack of potassium and boron in the soil;
• a plant with the upper part of the leaf blade eaten away does not form a head of cabbage - a sign of an infestation of the cruciferous flea beetle;
• A powerful plant with vegetative mass “bubbling with health” is a consequence of an excess of nitrogen in the soil.

How to feed cabbage to set fruit

Fertilizing the crop with mineral fertilizers is very important. Certain chemicals can not only help cabbage form a head but also improve the quality and ripening time of the harvest.

Feeding seedlings

The initial feeding of the plant for high-quality head formation is carried out at the seedling stage when the second or third pair of true leaves are formed on the plant.

Preparation:

• pour warm water into a container with a capacity of 8 liters;
• add 15 g superphosphate, 15 g potassium, 20 g urea;
• stir the solution and let it sit for two days;
• after infusing 0.5 of the finished concentrate, dilute it with 9 liters of water;
• pour 300 ml of liquid under each root of cabbage seedlings.

Fertilizing with boric acid and molybdenum

Signs of a deficiency of these elements in the soil under cabbage include the appearance of malformed leaves and the death of newly formed heads. If the soil lacks molybdenum, the plant will not form heads. Treat the plant with a solution when the head begins to form.

Preparation

• pour water into a 10 liter container;
• add 15 g of boric acid, 15 g of ammonium molybdate, 1 g of potassium permanganate, 10 g of zinc sulfate;
• Apply foliar feeding by pouring 0.5 liters of the prepared solution under each plant.

Fertilizer for weakened cabbage

If the plants appear weakened and the fruits are small, a double foliar treatment should be applied. The first spraying should be performed after the seedlings have established themselves, and the second when the head begins to form.

Preparation

• pour water into an 8-liter container;
• add 1 tablespoon of calcium nitrate, 1 glass of wood ash, growth stimulator "Epin";
• let the solution sit for 24 hours, strain;
• Apply foliar feeding with concentrate using a spray bottle.

Prevention methods

To take preventative measures against poor head formation, measures begin in late autumn. To do this:

• in the area where cabbage will be grown next season, the following are added per square meter during digging: 20 g of superphosphate, 25 g of potassium, 20 g of saltpeter;
• When planting cabbage seedlings, maintain a distance of at least 45 cm between plants;
• do not allow vegetables to be grown in partial shade or with closely planted tall plants;
• carry out timely watering and loosening of the soil under the cabbage;
• carry out preventive treatments with fungicides and insecticides.

Adviсe

By following the tips and recommendations for growing vegetables, you can not only achieve high-quality cabbage head formation, but also get a decent cabbage harvest.

1. When planting cabbage seedlings, add 15 g of superphosphate, urea, and potassium chloride to each planting hole.
2. Starting from mid-July, stop using nitrogen-containing fertilizers, as this substance will only promote foliage growth, slowing down the process of head formation.
3. During rainy summers, some of the lower leaves of the cabbage should be removed. This method will promote good air circulation in the root zone of the plant and aid fruit formation.

Reviews

Gardeners who have carried out treatments to improve cabbage head formation share their impressions:

Andrey, Pereslavl-Zalessky

I've been growing cabbage for several years now. However, I wasn't getting a decent harvest because some of the plants I planted weren't producing any heads at all. I learned about treating the cabbage with regular potassium fertilizer when it's forming heads. I decided to give it a try. I applied the solution to the leaves. Almost all the cabbage formed heads, and only two plants failed to produce any ovaries. But that's a result!

Anna, Yaroslavl

This year, my husband and I drilled our own well and decided to plant the entire garden with early cabbage. We watered generously—the seedlings drank plenty. However, in early June, just when the heads were about to form, we were met with a complete disappointment. Instead of heads, almost every plant had only leaves. Our neighbor, an agronomist, visited our beds and blamed the problem on overwatering. She advised us to pluck off some of the lower leaves and treat the cabbage with potassium and a growth stimulant. Following her advice, we saved the harvest, which, however, due to our oversight, ripened two weeks later.

Any gardener would be disappointed if, despite proper care, their plants failed to produce heads. Therefore, it's important to understand the underlying causes of this problem and address them promptly.