How to Grow: Lettuce is a cool-weather crop that thrives in the temperature range 60-65 degrees F, and if thoroughly hardened, most varieties survive temperatures as low as 20 degrees F. Cold-adapted varieties survive much lower temperatures.
What temp is too cold for lettuce?
Lettuce may cope with light freezing and even one or two hard freezes, but once the thermometer reads 25°F or below, the plants are in danger. That level of cold causes ice to form in the plant tissue, regardless of the amount of moisture in the air.
Is romaine lettuce cold hardy?
All types of lettuce, including romaine (also called cos) are cold-weather vegetables that can withstand brief frosts and even freezes, although they may experience some outer leaf damage.
Can romaine lettuce take a frost?
Lettuce is tolerant of cold temperatures for short periods of time, although growth will slow down. To protect lettuce in frost-prone areas, plant romaine or butterhead lettuce, which are the most cold-tolerant. When frost is predicted, cover the garden with sheets or towels to provide some protection.
What happens when lettuce gets too cold?
Freezing causes ice crystals to form within the lettuce’s cell walls. Because lettuce is so delicate and so high in water content, these crystals cause the cells to rupture, leading to unsightly and off-tasting crystallization.
Does romaine lettuce come back every year?
Lettuce does reseed. The blossoms are nothing special when they bolt. I collect seed from my heirlooms every year. Most seeds will over winter and sprout the next spring.
Can lettuce plants survive a freeze?
Because this vegetable is frost-hardy, lettuce should handle the cold pretty well. Typically, your plant can survive light freezes, meaning the temperature drops between 28 and 32 degrees.
At what temperature will lettuce bolt?
Bolting in lettuce is triggered by warm weather and the long days of summer, usually when the daytime temperatures climb above 75°F and nighttime temperatures are over 60°F. After bolting, lettuce leaves will taste bitter and grow slowly.
Do I need to cover lettuce plants?
Prevention is the best cure, so cover lettuces with insect-proof mesh (such as Enviromesh) from June until August, as this will prevent aphids getting to the roots. Some lettuces are resistant to root aphids.
Can lettuce survive snow?
Crops that can survive under snow—but not sustained freezing temperatures or ice–include asparagus, rhubarb, beets, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, cress, rutabaga, spinach, endive, horseradish, kohlrabi, kale, leek lettuce, onions, parsley, parsnips, radishes, and turnips.
Can you eat lettuce after a frost?
Lettuce, chard, and other greens are usually able to withstand a light frost without a problem. Chard, mustard greens, collard greens and kale are typically fine after a frost. Use your eyes and your head; if it looks okay, it should be fine. Anything that’s wilted or brown, throw it out.
Can you still eat lettuce after it bolts?
Can You Eat Bolted Lettuce? Yes, you can eat bolted lettuce but you probably won’t want to. Once lettuce begins to bolt it starts producing compounds called sesquiterpene lactones. They are the plant’s natural defense mechanism to ward off pests so that it can successfully produce seeds.
How do you harvest romaine so it keeps growing?
Cut the romaine heads off just above the soil line and below the lower leaves, using a sharp, clean knife. Cutting the romaine allows the plant to possibly grow additional lettuce. If you aren’t interested in growing a second crop, you can dig up the entire lettuce plant.
How many times can you harvest romaine?
Keep an eye on the inner leaves of the romaine head and give them time to continue growing. Once they’ve opened up and matured, they’re ready to harvest. This process can happen quickly, so check on your garden daily. You’ll be able to get 3–4 additional harvests by picking only the mature, outermost leaves each time.
Why is my romaine lettuce growing so tall?
ANSWER: Lettuce plants that suddenly start stretching toward the sky and growing extra tall are likely to be bolting. In the bolting stage, a plant stops focusing so much on producing foliage and starts to turn its attention toward reproduction, sending out a flower stalk that will eventually dry to release seeds.
Are plants safe in the garage during a freeze?
For a long duration of freezing temperatures or if a hard freeze is expected, then it will be best to move plants to the garage or inside. In flower beds, covering sensitive plants with a heavy covering of leaves can also help provide some frost protection.
How do you keep lettuce alive in the winter?
Growing lettuce in winter is easier than you think! The key is to select frost-tolerant varieties and pair them with a season extender like a cold frame, mini hoop tunnel, or polytunnel.
How cold can cucumber plants tolerate?
A temperature of 32 degrees Fahrenheit (0 degrees Celsius) or below will result in frost, which will kill cucumber plants. Any temperature below 50 degrees Fahrenheit (10 degrees Celsius) will result in slower growth of cucumber plants, and will eventually damage them.
At what temperature does lettuce spoil?
LETTUCE, ROMAINE OR COS – FRESH, RAW
Bacteria grow rapidly at temperatures between 40°F and 140 °F; romaine lettuce should be discarded if left out for more than 2 hours at room temperature.
How do you keep romaine from bolting?
3 ways to delay bolting lettuce:
- 1) Grow bolt tolerant cultivars. Certain varieties of lettuce, spinach, radicchio, cabbage, and other bolt-prone crops have been selected or bred to be more resistant to bolting.
- 2) Give lettuce some shade. Less light means lower temperatures and often more moisture.
- 3) Water and mulch.
Why is my lettuce shooting up?
Bolting is the natural progression of the life cycle in the lettuce’s attempt to reproduce. When lettuce bolts, it’s attempting to flower, which once pollinated will turn to seed. Lettuce isn’t so much on an ironclad timetable but instead responds to its surroundings to know when it’s time to reproduce.