7 Tips for Growing Great Lettuce in Hot Weather

7 Tips for Growing Great Lettuce in Hot Weather

Young lettuce

Do you have a feast or famine relationship with lettuce?  Does your garden have more lettuce than you can eat in the spring, and then nothing for the rest of the year?

Although lettuce loves to grow in cool weather, you can often continue to enjoy fresh tender lettuce throughout the summer, if you follow these seven simple tips:

1)     Choose heat tolerant varieties

Lettuce is a cool-season vegetable, but some varieties have been bred to better tolerate hot weather. Here are some of the most heat-resistant varieties that I’ve found:

  • Romaine – Jericho, Parris Island
  • Batavian – Nevada, Sierra, Tahoe
  • Iceberg – Anuenue, Minetto
  • Leaf – Red Sails, Royal Oak Leaf, Black-Seeded Simpson, Salad Bowl, Ruby
  • Butterhead – Kinemontpas
  • Bibb-Romaine – Winter Density (also heat tolerant)

2)     Germinate your lettuce seeds in cool soil

Lettuce seed often refuses to germinate if the temperature is above 80 F.  During hot weather, you can start lettuce seed indoors under lights, if your home has air conditioning.  Or you can store your seeds in your refrigerator, and cool the soil down in the garden bed for a few days before planting (water the soil well, and cover it with a heavy mulch or burlap). In really hot climates, you can even put a layer of ice on top of the soil right after planting lettuce seeds outdoors.

3)     Provide lettuce with extra shade

When summer temperatures regularly exceed 85 F, lettuce will greatly benefit by growing in some shade.  Give your lettuce plants afternoon shade, either on the east side of a building or in the shade of taller plants.  You can also protect them with a 40% shade cloth. Just be sure to elevate the shade cloth to allow plenty of air circulation around the plants.

4)     Keep the soil evenly moist

If you’re transplanting your lettuce, water your seedlings 24 hours before transplanting, again 1 hour before, and then immediately after planting them in the garden outdoors. This will help to reduce transplant stress.  Whether you’re direct seeding or transplanting your lettuce, it’s very important to keep the garden soil evenly moist at all times. If you’re growing lettuce in containers, they will greatly benefit by being grown in self-watering containers, which naturally keeps the soil evenly moist.

5)     Plant a few seeds every 7-10 days

In hot weather, lettuce doesn’t usually last very long. If you want to enjoy fresh lettuce each week, be sure to start a small number of plants every 7-10 days or so.

6)     Harvest your lettuce as baby greens

If your plants tend to bolt in the heat before forming a head, just harvest the lettuce as baby greens instead. When they are only 4” high, cut the leaves about 1” above the soil. The cut stumps of the young plants will often grow another crop of leaves again.  In humid summer climates, give your plants extra spacing to increase air circulation and reduce disease.

7)     Harvest the lettuce early in the day

For the sweetest greens, harvest lettuce in the early morning. Studies have shown that lettuce leaves contain over twice as much natural sugars early in the day, compared to mid-afternoon.

By following these seven simple steps, you can often continue to enjoy fresh succulent lettuce throughout the summer.  What varieties of lettuce have grown well in your summer garden?

  • Annalene says:

    Hi Debra

    Thank you so much for the advice.
    I love fresh greens, and struggling to find them in Thailand (recently immigrated).
    Do you have any advice on growing salad greens in tropical climates?

    • Debra says:

      I have no gardening experience in your climate. I would suggest growing greens that are adapted to heat, possibly providing them with partial shade (especially in the afternoon), and keep them watered well. Good luck!

  • Sekar A says:

    Its awesome. In my place the temperature will be +- 110* IN SUMMER, Is it possible to grow lettuce under 60% Shade net. PLEASE help me with your Knowledge..
    Thank you

    • Debra says:

      Sekar, with those temperatures, there are very few vegetables that will grow well or at all. Perhaps some gardeners experienced with an extremely hot climate would have helpful suggestions for you. I personally would recommend focusing on growing plants during a cooler season. Sorry!

      • T Tommy says:

        Morning sun, afternoon shade. Mulch, mulch, mulch. Water, water, water. If soil is sandy, desert soil, add organic (manure, compost) Calcium bentonite addition will aid Sandy soil water retention.

    • Dante says:

      The shade may not be enough, you may benefit from a mister hooked up via a drip line – Good Luck!

      • Debra says:

        Thanks for the tip. I wonder if misting is more helpful in a hot dry climate versus a hot humid one. I have no experience in using it, as my climate isn’t that severe.

    • YL Calif. says:

      Plant Palo Verde (desert) trees amongst your garden area. Deciduous during winter and 25% shade during the summer when it leafs out. It’s like planting a greenhouse.

  • Jenni says:

    Hi Debra,

    Thank you for giving this tips. Hope to read more of your posts!

  • Marc Scheidecker says:

    Debra, I have been following your web site now for about a year. I have always found your advice and comments to be solid and completely reliable. I am also going to get your book on verticle gardening. I teach gardening here in Portland, Oregon, and I find your thoughts on gardening to be a continual pleasure and source of joy. I think this is so because it always validates what I am doing in the garden and
    in the classroom. Your website is a pleaure to read.

    Thank you so much!

  • Carolyn says:

    Thanks Debra, I’m going to plant some lettuce today and try your helpful hints.

  • Nina Templeton says:

    Thanks for the tips. Usually get sick of lettuce by the time other things start coming in , but this is good info to tuck away in my brain.

  • >