Buttoning broccoli: why broccoli forms a small misshapen head
Broccoli is a cool-season vegetable that grows on fertile, well-drained soils rich in organic matter. Like any plant, broccoli can be affected by pests or diseases, and can also suffer from problems caused by environmental stress – such as bad broccoli heads. If your broccoli plants are budded, then this article is for you.
What is a broccoli button?
Broccoli seedlings are buttoned when the broccoli is small or has no head. Broccoli buttoning is the development of small heads or «buds» that are not marketable to a commercial grower when the plant is immature.
Buttoning of broccoli occurs mainly in young plants when they are exposed to several days of cold temperatures around 35-50 degrees F. (1-10 C). However, cold temperatures are not the only reason for bad broccoli buds.
Broccoli plants are sensitive to prolonged changes in their environment. A number of conditions can affect the plant, resulting in a change in vegetative growth early in the plant’s development. Other stress factors, such as insufficient water, lack of nitrogen, excess salt in the soil, pests or diseases, and even competition from weeds, can contribute to broccoli fertilization problems.
Transplants are more likely to be buttoned than fast-growing young plants, as are plants with exposed roots. The good news is that the problem of broccoli with small or no heads can be solved.
Solving the problem of swollen broccoli
To prevent broccoli from being buttoned, adjust your planting dates if you are in an area where cold snaps are frequent, so that the plants are mature enough to produce a good-sized head or too immature to be cut prematurely.
If you use transplants, they must have 4 to 6 mature leaves and a healthy, well-developed root system before they begin to function. Larger, more mature grafts tend to form tiny early buds (budding) that flower too early. Sow the seeds for the planned transplants about 5-6 weeks before planting.
Maintain a consistent watering program. Water broccoli plants thoroughly and infrequently, about 1 to 2 cm of water per week. If possible, use drip irrigation to conserve water and apply mulch around the plants not only to help retain water, but also to slow down weed growth. Organic mulches such as straw, shredded newspaper or pieces of glass are ideal.
Plastic mulches also conserve water, reduce weed growth and promote earlier maturity through transplanting. Warm blankets and cloths protect seedlings and seedlings from frost and help control broccoli budding problems.
Finally, be attentive and constant when it comes to fertilization. You must apply a nitrogen-based fertilizer (21-0-0) at the rate of one cup of ½ per 3-metre row, four weeks after transplanting or thinning. This will stimulate more vigorous plant growth. Apply an extra cup of ¼ when the heads reach the size of a quarter. Then, when the main head has been picked up, apply an extra 5 cm of fertilizer to the side of the plant and irrigate the soil. This will encourage the development of side shoots.
Follow all of the above instructions and avoid buttoning your broccoli, and instead harvest large, beautiful broccoli crowns.