The term “bolting” means a plant has stopped the production, growth stage, and is turning to the production of seeds. It is also referred to as “going to seed”, which is exactly what the plant is focusing upon…… propagation of the species. It is a normal part of a plant’s life cycle to produce seeds. Unfortunately, when a vegetable plant bolts, its harvestable days are over.
Bolting is common among lettuces, onions, cabbage, Bok Choy, and other cool-weather crops.
Here are a few examples of the signs to look for:
Lettuce is turning a lighter green and is drier looking. Leaves taste bitter and dry. The plant is growing taller, yet it is not as wide as normal.
The plant shoots a stalk upward producing little if any leaves. Seed pods begin to develop.
Onion plants produce a long, tall stem. A flower appears at the top.
The head of cabbage (or Kale) plants split, and a stem emerges. The stem ultimately develops flowers and later seeds.
This is caused by stress on the plants, and sometimes, longer days. The most common plant stressor is high temperatures and humidity.
Lack of sufficient soil moisture is another common cause of bolting.
Plants may also bolt due to a lack of nutrients, disease problems, or insect infestations.
Once your plant has begun to bolt, there is no stopping or reversing the process. But, you can do things to delay plant bolting. Look to eliminate factors that cause a plant to bolt.
Note: Delaying or avoiding plant bolting, requires steps to be taken BEFORE bolting begins.
The most common cause of bolting is high temperatures. How does one go about lowering the outdoor temperatures? Unfortunately, there is little a gardener can do to provide relief. If the plant is being grown in a container, the container can be moved to a shaded area during the hottest part of the day. Or, it can be brought inside, into air-conditioned comfort. For garden plants, misters used at midday, or shade covers offer some relief.
Dry soil is perhaps the next biggest stress that encourages your plants to bolt.
If your plant is under stress, due to any other factor, the cure is simple…. eliminate the stress.
Grow cool weather crops in spring and fall, avoiding mid-summer heat.