Growing lettuce in the summer heat

By on June 12, 2013

'Little Gem' Romaine lettuce sparkles in your garden, even in hot weather.

It seems unfair—just when we really need lettuce as the foundation of a summer salad, the lettuce wants to pack up and spend its summer at Lake Tahoe (or some other cool spot).

Here’s how you can have your lettuce and heat it too.

bibb butterhead lettuce

Horses bolt and so does lettuce

Lettuce prefers the cool days of spring and fall with air temperatures in the 60s. When the weather warms up lettuce will often bolt right out of your garden bed. In the world of lettuce, bolting means that the plant sets a flower and grows a seed stalk—which makes the lettuce leaves bitter.

What causes bolting? A combination of more sunlight in the longer days, and the hot summer weather.

loose leaf lettuce

How to grow lettuce in the heat

What’s a summer gardener to do?

First, alter your lettuce growing climate to make it cooler and shadier.

Second, grow heat tolerant lettuces.

romaine or cos lettuce

Cool down the summer weather for your lettuce

As gardeners, we adjust to the seasons. If your spring vegetable patch is in full sun then don’t plant summer lettuce there—instead, plant summer lettuce where it will get morning sun and afternoon shade (morning shade and afternoon sun will give too much heat).

This might be the time to plant lettuces in amongst your part-shade ornamentals. Want variegated foliage? We’ve got some stunners, like ‘Freckles’, shown above.

Can’t move your vegetable patch? Then adjust the sun’s rays by providing a shade cloth covering for the lettuce part of the bed. Need support for your shade cloth? We explain how to build low tunnels over your raised beds.

crisphead iceberg lettuce

The ABCs of growing lettuce

Tricia plants, grows, and harvests lettuce in our latest video.

There are four basic groups of lettuces: Bibb, Crisphead, Leaf, and Romaine. We make it easy for you to find the lettuce you want.

Start with our Seeds page, scroll down past the purple bar and pull down in the button that says Lettuce Type.

All four kinds of lettuce are listed, along with Mixes, and the all-important Heat Tolerant lettuces (those are the ones you want for your summer garden). You’ll see all the lettuce varieties we carry, in seed packs on up to bulk sizes.

Heat Tolerant Lettuces

There are Heat Tolerant varieties in all four lettuce groups:

Bibb  Buttercrunch, Speckles, Summer Bibb, Summer Bibb Blend

Crisphead  Michelle

Leaf  Black Seeded Simpson, Green Salad Bowl, Red Deer Tongue

Romaine  Little Gem, Parris Island Cos

Container gardening—an easy way to modify climate

One of the joys of container gardening is that you get to play Mother Nature.

Is the sun too strong for your lettuces? Pick up the container and move it to a part-shade location. If you need help moving heavy containers, try the QwikLift, which raises up to 150 pounds.

Our vegetable gardens are rarely right outside the kitchen door, but you can grow containers of Leaf lettuces just steps away from your kitchen sink—cut some leaves, rinse, spin, toss, and eat.

Head lettuces like Romaine, Bibb and Crisphead need to grow about 50 days to harvest, so let them get on with it out in your vegetable bed. But the Leaf lettuces are ideal for containers—pick the outer leaves and let the center continue to grow. This is called a “cut and come again” method of harvesting.

Whether you grow in containers, mixed in with your ornamental plants, or in a vegetable garden—plant some lettuce this summer.

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