If you don’t have a garden outside your igloo, your lettuce crop will probably be over by late June, or maybe even earlier. As the weather gets warmer in the summer, these cool-weather plants are often the first in my garden to send up flower stalks.
I’ve always thought it was unfair that Mother Nature gave us gardeners so many juicy tomatoes in the summer but none in the winter, when salad greens are at their most fresh, sweet, and plentiful.
Red leaf amaranth, spinach chard, and a few Asian mustards are just a few of the heat-tolerant greens I grow for my summer salads. For a while, I even tried to grow regular spinach under a fruit tree. That spring-sown spinach didn’t usually bolt too early in the summer, but it also didn’t grow much more than a few inches and a few leaves. As I found out, too much shade was just as problematic as too much sun.
After years of trying different things and many plants dying, I finally found the best lettuces that don’t mind being hot in the middle of summer.
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Lettuce is typically considered a cool weather crop, ideal for spring and fall planting. Once summer heat sets in, lettuce often bolts, becoming bitter and inedible But with some careful variety selection and a few cultural techniques, you can continue harvesting tasty lettuce all summer long
Growing lettuce in the hot summer months may take more effort than spring and fall crops but it can be done with great success. Follow these tips to keep your lettuce greens happy despite the heat.
Choosing the Best Lettuce Varieties for Summer
Not all lettuces are created equal when it comes to tolerating heat Some types and varieties are far more likely to thrive in summer than others
Focus on Leaf Lettuce
Leaf lettuces are inherently more bolt tolerant than head forming varieties. Loose leaf types like oakleaf, red sail, green leaf, and red leaf can be harvested a few leaves at a time over a long period, making them ideal for continued production.
Look for Heat-Resistant Cultivars
Many classic lettuce varieties bolt quickly in heat, but some newer cultivars have been bred specifically for warm weather tolerance. When seed shopping, look for keywords like “heat resistant,” “slow bolting,” or “summer lettuce” to find varieties optimized for summer harvests.
Try Warm Season Specialties
Certain lettuce types originate in warmer regions and are naturally more heat hardy. Try varieties like Latin lettuce, which gets its name from Central America, or Jericho lettuce developed in the Middle East.
Grow Lettuce Under Hot Weather Conditions
Creating the right conditions will help your lettuce thrive in the dog days of summer. Follow these tips:
Provide Afternoon Shade
Lettuce needs full sun in spring but appreciates some shade relief as temperatures climb. Plant it near taller crops like tomatoes or pole beans that will shade the lettuce in the hottest part of the day. Or use shade cloth hung over the lettuce bed.
Use Mulch
A light mulch layer helps cool the soil and reduces moisture loss. Grass clippings or straw work well. Just avoid piling mulch up on the lettuce crowns.
Water Frequently
Don’t let plants dry out since drought stress encourages early bolting. Water daily if needed, aiming for consistent moisture in the top few inches of soil where lettuce roots grow.
Sow Under Cover
You can gain a few degrees of protection by starting seeds indoors or in a cold frame instead of direct sowing. Transplant outdoors once the soil warms up.
Growing Lettuce to Maturity in Summer
Getting seeds to germinate and seedlings established in hot weather is the first challenge. Keeping plants actively growing and delaying bolting requires more strategies.
Harvest Frequently
Cutting outer leaves often, before they mature, keeps the plant in vegetative growth longer. Don’t let plants sit untouched for long.
Replant Immediately
As soon as you see the central leaves starting to elongate and emerge upward, pull out the entire plant, roots and all. Replant it right away in a shadier spot and the shock will reset its growth.
Avoid Crowding
Thin lettuce to recommended spacings to prevent competition and give each plant enough room to grow strong. Crowding stresses plants.
Keep Soil Nutrients Up
Fertilize lightly with a organic balanced fertilizer when planting and again halfway through the growth cycle to maintain optimal nutrients for plant health.
Control Pests
Insects like aphids add extra stress, so be diligent about checking for pests and taking control measures ASAP to keep infestations from flaring up.
Maximize Seed Germination in Hot Soil
Getting lettuce seeds to sprout in midsummer takes some finesse. Here are tips for success:
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Plant in light shade or use shade cloth to cool the soil.
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Water the bed thoroughly before planting and mist soil daily.
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Cover seeded beds with boards or burlap to maintain even moisture.
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If seeds don’t germinate well, soak them in cool water for a few hours before planting.
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Sow in the evening when temperatures start to drop.
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Try pelleted lettuce seeds which helps them absorb moisture better.
With some added attention, your lettuce can thrive despite hotter temperatures. Be diligent about keeping plants actively growing with frequent cutting, ample water, and preventative pest control. With the right techniques, you can enjoy homegrown lettuce all summer long!
Grow loose-leaf varieties.
In general, loose-leaf lettuces are more heat-resistant and slower to bolt than lettuce varieties that form heads. First, you should try a butterhead lettuce. Then, any kind of green leaf, red leaf, or batavia lettuce will do. These are the ones that work best for me and last the longest in the summer, and there are a lot of them to choose from.
8 tips to keep lettuce growing in the heat of summer
You can keep lettuce going all summer long with a few simple tricks up your sleeve. Here’s what I do in order to harvest lettuce well into September:
How to Grow Perfect Not Bitter Lettuce In Summer
FAQ
Can you grow lettuce in hot summer?
What temperature is too hot for lettuce?
Does lettuce like sun or shade?
How often do you water lettuce in hot weather?
Do you grow lettuce in the summer?
You grow lettuce in the summer! 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. Lettuce prefers the cool days of spring and fall with air temperatures in the 60s.
Is lettuce a cool season vegetable?
Lettuce is a cool-season vegetable, and in most home gardens, it is planted in the early spring, harvested in late spring to early summer, and then discarded in favor of other vegetables for the middle of the summer.
How long does lettuce take to grow?
It takes up relatively little space, has a short (5-6 weeks from transplant or 9-11 weeks from seed) growing cycle when it’s healthy, and there is always high market demand. Hundreds of lettuce varieties are grown around the world.