I love lettuce.
It’s one of the first harvests of the spring, and can be one of the last harvests of fall, too. As a crop it’s diverse: from butterheads to crisp Batavian, frilly red and green leaf to the sturdy crunch of romaine, from mini-sized little gems to huge heads that fill an entire plate.
Lettuce is fast and easy to grow, but if you want a consistent harvest all season long, there are a few important things to know.
Lettuce loves cool weather.
Though lettuce naturally thrives in spring, certain diseases like downy mildew are more apt to show up in damp, cool weather. Look for varieties with downy mildew resistance.
Some varieties of lettuce will only germinate in temperatures under 65º, but even those that tolerate more heat will thank you for keeping them under 70º during germination.
Seed new successions weekly for a consistent harvest
In the summer, you can beat the heat by keeping freshly seeded trays in the shade, either on your porch or under a shade cloth. Consistent moisture is important for even germination, and water will help cool the soil.
Seedlings are ready to be transplanted a month after germination, and can be popped into open space in the garden.
Hot, dry weather can affect taste
Lettuce can turn bitter in the summer with long sunny and dry days. To avoid this, look for heat-resistant varieties. Consistent watering can also help by cooling the soil; water in the evenings and early mornings to avoid quick evaporation under the mid-day sun.
Extend the season with row cover
We’ve harvested lettuce from the field all the way through November. Avoid frost by covering lettuce with a floating row-cover like reemay (also called agribon). Choose quick-growing varieties that will head up even as the daylight shortens. Fall is another season to look for downy-mildew resistant varieties.
My favorite lettuce varieties by season:
- Black Seeded Simpson: one of the earliest to mature, this bright green leaf lettuce is tender and resistant to downy mildew.
- Magenta: a beautiful, crisp red leaf that bridges the gap between spring and summer, with downy mildew resistance and heat tolerance.
- Encino: a large head of tender wavy oak leaves, this is a stand out beauty that also grows wonderfully in the shift of spring to summer.
- Nevada: a crisp green-leaf type, Nevada is heat tolerant and remains sweet through long sunny days.
- Lovelock: Red tipped with a green center, this is my all-time favorite summer lettuce. It holds well in the field without bolting or turning bitter, and offers a refreshing crunch to salads, sandwiches, and burgers alike.
- Jericho: this green romaine stands up to summer’s heat and is an essential ingredient in any respectable sandwich.
- Pirat: a butterhead with a red blush and green center, Pirat is delicious with a buttery texture; it’s resistance to tip burn and downy mildew make it a great variety to bridge between summer and fall.
- Pomegranate Crunch: this red mini-romaine is compact, fast-growing, and beautiful to boot. With it’s speed and downy mildew resistance, it fits well into the fall slot.
- Spretnak: a green mini-romaine to pair with pomegranate crunch.