Bolting is the process of premature flower formation in response to high
temperatures, as well as drought and starvation. This unwelcome occurrence in leafy plants
such as broccoli, cabbage, lettuce, and spinach, takes the plant out of its leaf producing
mode and switches over to flower and seed production.
Many vegetables are divided into two groups: cool season and warm season
vegetables. Although in Hawaii seasons may vary little in temperature and many
vegetables can be grown year around, some will do better when planted within
the given time frame.
Broccoli and lettuce are cool season vegetables. As long as the
temperatures remain cool, the lettuce will continue to produce tender leaves,
and the broccoli flower buds will remain closed. Generally lettuce and broccoli
are planted from September through March/April.
During the hot summer months plants can bolt. At higher elevations, cool season vegetables
such as lettuce, beets, broccoli, cauliflower, chard, kale, peas, turnips and mustard, may be successful
planted in late spring and summer.
Warm season vegetables include tomatoes, cucumbers, melons, squash, peppers,
corn and eggplant.