Preventing Bolted Lettuce

The term “bolting” is a confusing one for new gardeners.  Most have heard the term “gone to seed,” but few have heard “bolting.”  Simply put, bolting is when plants begin to go to seed – they start putting all their energy into growing reproductive organs (seeds, flowers, etc).

When it comes to bolting, lettuce is one of the most difficult plants for the vegetable gardener to deal with. Whatever the type, leaf or head, lettuce tends to bolt very quickly, putting out long seed stalks.  Once it starts, you literally have only a couple of days to deal with it before the lettuce crop is ruined.  The good news is that there are various planting techniques to help prevent bolting.

Causes for Lettuce Bolting

First, understand that every plant’s ultimate goal, no matter what it is, is to reproduce.  This is what drives plants to grow in the first place. Our job as vegetable growers is to harness this tendency without letting it go all the way.

The primary trigger that sets off bolting in most leafy greens is heat. These plants prefer cooler temperatures during their primary growth period. So when a relatively mild or cold spell is suddenly met with a prolonged (more than a handful of days in a row) warm or hot spell, expect these plants to bolt.

Most cool season crops (beets, spinach, radishes, turnips, etc.) are the same, in fact.  So if one is going to bolt, they all will.  This can affect a large chunk of your garden.

Tips for Growing Lettuce

To prevent bolting, planting leafy lettuces in the spring and continually harvesting (cutting them back) during the year will likely prevent bolting and provide lettuce leaves for most of the summer.  For head lettuce, such as iceberg, consider planting them as a fall crop so they mature as the weather is cooling. Another option is to plant in the shade so that the lettuce doesn’t get full sun all day.  This can prevent bolting as the plant will not have the energy, but it will also stunt productive growth. Some gardeners even result to digging up their plants and replanting them (often in the same spot); the shock will stop bolting immediately.

Starting your lettuce indoors well before the frost lifts and growing them in buckets or suitable containers until ready for transplant (likely after you’ve already begun to enjoy small cuts from the plants) is another option. The shock of the transplant plus the earliness of their planting means that the lettuce will be well through its lifecycle by the time the heat of summer really sets in.

The best thing to do when growing lettuce is to be mindful of the needs of each particular variety and to plant varieties recommended for your region.  Growing the right type of lettuce in the right way goes a long ways towards preventing them from bolting and going bitter. Watering daily, even just for short periods, can make lettuce more forgiving, helping with bolting.  Once the seed shoots appear, you can trim them back, but be prepared to do this daily in order to keep them back.

More Resources on Bolted Lettuce:

Iowa State University – Lettuce
University of Illinois – Lettuce