It is quite disappointing when you plant vegetables or herbs and they become seedy after a couple of weeks. Instead of the plants utilizing the available energy to form bulbs or leafy green bits that you want to harvest, it instead forms flowers and seeds. Naturally, most plants reproduce through the production of seeds.
Bolting is the formation of a flowering stem on horticultural crops before they are harvested. The production of seeds shows that the growing season of the crop is coming to an end. Once bolting happens, the plants no longer grow and they either go dormant or die. Since all the energy is focused on the production of seeds, the crops become woody, tough and tasteless. The plant withdraws water and sugar from the bulbs and leaves and uses it to feed the flowers. Some plants such as lettuce produce bitter compounds to put off foraging predators.
Causes of Bolting to Seed, and How to Prevent It
Stress: when they are exposed to stress, plants mostly flower. Environmental factors such as temperature, weather, pests, and diseases stress the plant. For instance, cold weather makes the plants to become dormant. Lack of warmth alters the growth cycle and in the process the plant bolts. Fluctuations in temperature also result in bolting. Low temperatures cause the plants to become dormant while warm temperatures promote plant growth. When these temperatures fluctuate, the plants end up forming flowers.
Over-fertilization: Application of large amounts of fertilizers causes vigorous and uneven growth of crops in their early development and in the process of forming flowers.
Loose soil: For instance, in onions, loose soil makes the onion roots to be easily disturbed. This causes stress on the onion plant and it responds bolting.
How to Delay Bolting
Although bolting cannot be prevented, it can at least be slowed. Various ways that can be taken into consideration to slow the process include:
Planting bolt-resistant varieties. Some varieties are resistant to bolting. In Kenya, for instance, onions are exposed to high temperatures which can easily initiate flower bud formation. For biennials such as carrots and onions, resistant varieties are hence a good option.
Sowing time: Some biennial vegetables are sensitive to cold snaps and hence the sowing time can be delayed up to when the temperatures are stable.
Mulch heat-sensitive vegetables and herbs. Mulching will offer a controlled environment, providing the desired temperature for forming heads in plants such as broccoli and coriander. If the roots get hot, the plants will form flower buds.
Harvest the crops early when the temperatures are cool.ince you keep cutting off growth from plants such as spinach, kales, lettuce and broccoli, the plant is stimulated to replace the cut part.
Use the right fertilizer. Different fertilizers offer different nutrients to the plants. When applying fertilizers in vegetables and herbs, you should be careful. Some fertilizers are meant for leaves while others are specifically for flower and fruit formation. For instance, if you apply fertilizers meant for fruiting plants on leafy vegetables, the nutrients will encourage the plant to form flowers. Leafy vegetables and herbs require fertilizers with high nitrogen (N).
Some of the
crops which tend to bolt include cabbage, lettuce, brassicas, spinach,
beetroot, onions, carrots, turnip, arugula. Farmers need to seek agronomical
support to understand important growth patterns to get maximum yields from
their crops. With support, farmers can get adequate information on problems
that their plants are exposed to and how to prevent them.