Another option is to plant vining crops, such as cucumbers, at the bottom of a lean-to trellis. It’s past its prime. If you want to take extra steps to protect your plants, you have a few options. Growing Lettuce in Extreme Summer Heat – In a Vegepod! We’ll also get into ways you can protect lettuce from cold weather and how to prevent bolting in warm weather. Growing lettuce in containers allows you to place the plants outdoors during good weather and move them inside to protect them in severe weather. A cool-weather vegetable, lettuce (Lactuca sativa) has many varieties, and they all germinate and grow best in cool temperatures, such as those in U.S. Department of Agriculture plant hardiness zones 4 through 9. Lettuce is a cool weather crop, so it prefers cooler temperatures for its growth. learn more about Cherokee lettuce from Johnny’s Selected Seeds. You can combine two or more of these methods to keep your lettuce even cooler and extend the season to enjoy a longer harvest. However, lettuce loves the cool weather (80 degrees F or less) and is challenging to grow … Lettuce is a cool-weather crop and a garden favorite, since it is the basis of many delicious salads. Intense sunlight for 12 to … This shade cloth from Gardener’s Supply Company can be used with hoops for support. For example, there are many heat-tolerant lettuce varieties that can withstand warmer temperatures than their cousins before they begin to bolt (more on these varieties later). However, to achieve best results, it is recommended that lettuce be grown on sandy loam soil and clay loam soil. The best temperature for growing lettuce will depend on the growth stage. Lettuce seeds can germinate just fine at higher temperatures that would cause established lettuce plants to bolt (produce seeds and become bitter). to read some of my most popular posts, check out the “Best of GreenUpSide” page here. For extra early crops, start plants inside 3 to 4 weeks before transplanting. learn more about Adriana lettuce from Johnny’s Selected Seeds. 10. Lettuce seedlings should be protected from the wind because the young plants are rapidly dried out. When temperatures dip below 2 degrees celsius, consider covering plants with a row cover, cloche or other apparatus. Lettuce germination and early growth rates are largely determined by temperature. Lettuce can survive in temperatures down to 10 degrees Fahrenheit or -12 degrees Celsius. Use this chart to determine if the soil temperature in the garden is right for seed starting the crop you want to plant. Not only is it rewarding to pick your own fresh produce, but once picked, lettuce will continue to grow, giving you successive harvests of fresh greens. It grows in any location with the sun and you can start indoors. There is nothing I love more than heading out to my garden to pick fresh, crisp greens and bringing it indoors to make a salad. As an added bonus, shade cloth can protect lettuce from birds. If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. If you see an elongated crown on the lettuce plant, pull it up and compost. Depending on its variety, lettuce seed can germinate when the soil temperature is 35 to 80 degrees Fahrenheit. The maximum temperature for lettuce seed germination is 85 degrees Fahrenheit (29.4 degrees Celsius). When a sudden hard frost threatens, your lettuce might be able to survive. For instance, in some areas, people go on about how nothing lives through the summer once it gets beyond temperature x. As with many crops, there are differences between varieties within the same species. But what happens when temperatures dip toward the freezing mark? As the cucumbers grow, they will provide shade for the lettuce. Lettuce seeds are another leafy vegetable that is easy and quick to grow. This can make the difference for their survival when extreme cold is on the horizon. This vegetable gives higher yield when the temperature is maintained no higher than fifteen to twenty degrees Celsius. If the lettuce leaves get large enough, the plant will think it is “done” growing, and will enter the next phase of its life: producing seeds. At 70 to 80°F, the plants flower and produce seed. ~Jonathon. Lettuce is a cool weather crop, so it will bolt (grow tall, then produce flowers and seeds) in high temperatures. You can protect an entire row of lettuce plants from cold by using a row cover. Benjamin Shorter has been a writer for publications such as the "New Brunswick Telegraph-Journal," "National Post" and the "Edmonton Journal" since 2001. Temperatures inside a covered seed tray will be closer to the maximum temperature reading and, unless the spot cools off considerably at night, will remain quite stable, a further factor to consider. Suitable air temperatures range from 12 – 21C, with 18C the optimum. Pelleted seeds make it much easier to sow the smallest seeds.So, what are pelleted seeds? learn more about Jericho lettuce from Johnny’s Selected Seeds. However, it also means that the lettuce leaves will become bitter, to the point where most people would not enjoy eating them. Want to learn how to plant sprouted potatoes to grow your own food? You can learn more about cloches in my article here. Grow above 70 F during the day and above 60 F at night. Lettuce can tolerate a few days of temperatures from 80 to 85°F, provided that nights are cool. Celery is a Mediterranean plant that grows best in temperate climates with temperatures between 59 and 70° Fahrenheit (15-21° Celsius). Note that this can vary depending on the variety of lettuce and any heat protection (shade cloth, etc.) In this article, we’ll talk about the ideal temperatures for lettuce germination and growth. Are there varieties of iceberg lettuce and cabbages that can grow on low altitudes of less than 1000 feet and temperatures ranging 28 to 33 degrees Celsius along the equator (tropical climate) Ali April 26, 2018 One of the best ways to grow lettuce for a longer time period in a hot climate is too choose a heat-tolerant lettuce variety. Harvested fruit and vegetables are living organisms. According to the Michigan State University Extension, lettuce is a plant that is hardy to hard frost. Frosts, freezing temperatures and snow will not kill them. Children will see the seeds sprout and get their first leaves, then their real leaves and grow to harvest—what an excellent activity for the whole family. A cloche acts as a mini greenhouse, trapping heat from sunlight in the air and soil underneath it. Be careful when hardening-off plants not to expose them to cold temperatures. Scratch the surface, or lightly cover the seeds with a sprinkling of soil. Germinating lettuce seeds is not difficult, but the task has some environmental requirements. However, this isn’t the only way to do it. Lettuce may grow on different kinds of soil. Hi, I'm Jon. The following methods will all help with this to some degree (no pun intended!). Lettuce seeds typically sprout in two to eight days when soil temperatures range between 12 to 17 degrees Celcius. Depending on the grade of the shade cloth, it can provide up to 10 degrees of heat protection for your lettuce! This crop prefers a loamy soil with a high organic matter content. If you harvest your lettuce as it matures, you can extend your growing season by at least a few days. Most will check both the maximum temperature (usually during the day) and the minimum temperature (at night), so leave them in place for 24 hours for a complete picture. The best time to plant the seeds is during cool weather. Most cool season crops germinate at maximum soil temperatures of 90 degrees, except for lettuce and spinach, which require temperatures … So plant more seeds than the number of lettuce plants you need. (Plus 7 Heat Tolerant Varieties). In this temperature range, lettuce seed takes only 2 to 4 days to germinate. The lettuce will still grow after it has started to bolt. For example, you can bend a flexible plastic rod into a half-circle and drive the two ends into the ground. Lettuce seedlings are available at farmer's markets, nurseries and home garden centers, and lettuce also can be grown through direct seeding in the soil of a garden bed or growing container. The time for lettuce seed germination will vary, depending on soil temperature. You also know how to protect lettuce from temperature extremes to extend your harvest. Sow 3 seeds per pot in 2-inch pots. Plant when soil temperatures warm up to 35 to 40 degrees F. In general, cool season crops can be planted two weeks before the last frost date. First, you can plant your lettuce next to taller plants. The soil should be kept moist at all times during the germination period. Since a cloche is clear, it still allows sunlight in so that plants can continue to grow. However, the leaves of lettuce will become bitter after the plant has bolted, to the point where the leaves will be inedible. The table below summarizes the temperature ranges for lettuce seed germination, in both Fahrenheit and Celsius temperatures, based on information from the University of California Extension. that you can provide. University of Illinois Extension: Lettuce, North Carolina State University: Lettuce Production, University of Arizona: Seed to Seed -- Fresh Produce Safety, How to Sprout Lettuce Seeds in Hot Weather. Luckily, there are a few different ways to provide shade for your lettuce. a hydroponic lettuce is still a growing plant with roots and leaves, an onion or potato can re-sprout and grow into a new plant under the right conditions). This shade cloth from Gardener’s Supply Company can be used with hoops for support. For example, if a hard frost comes suddenly after warm weather, then lettuce may not survive. Frost damage on leafy vegetables doesn't render the plant inedible like a disease. The apical meristem of young lettuce plants is near the soil surface, so plant growth is often more closely matched to soil temperature than air temperature. After germination, the ideal temperature for growing lettuce is 55 to 65 degrees Fahrenheit (13 to 18 degrees Celsius). 5. Combined with high humidity, high temperatures can encourage the growth of mold, which is another threat to your plants. Growing Lettuce in an AeroGarden is a fantastic way to get your children involved and use the leaves to make their salad sandwiches. When temperatures are warmer than 70 to 75 F, lettuce seed may not germinate. Growing lettuce indoors results in a steady supply of fresh, leafy greens throughout summer or even year-round if you wish. Lettuce may bolt in response to the stress of high temperatures, and the leaves may become bitter as the plant puts its growth into flowering (see photo at right). © Copyright 2020 Hearst Communications, Inc. Temperature and light to grow lettuce Average room temperature of 16 to 21 degree Celsius is best for growing lettuce. Row covers can provide a few degrees of cold protection for your lettuce. Just remember that lettuce do need some sunlight, so don’t leave your plants covered all day in heavy shade. Use a handful of pine needles around tender seedlings to help prevent wind damage and also provide support. Tip: Harvest sooner rather than later to avoid a bitter lettuce flavor. If they are growing in a warmer environment they will think that it is already summer and thus start producing seeds, which means that they will not be edible anymore (well you could eat it, but the taste will be horrible). If, however, you plan to harvest only small, tender leaves, then you can have more plants with less space between them. learn more about lean-to trellises and other designs in my article here. Leaves wilt, toughen, and get bitter if the plant becomes water stressed in heat. learn more about Coastal Star lettuce from Johnny’s Selected Seeds. This is a normal part of a lettuce plant’s life cycle. That would be 77 degrees Fahrenheit. 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). The best temperature for growing lettuce is from 55 up to 70 degrees Fahrenheit (12.8 to 21.1 degrees Celsius). There’s no ideal climate for all lettuce types, but most grow best in cool weather. A hard frost is defined as a temperature less than 28 degrees Fahrenheit (-2 degrees Celsius). Day length affects onion growth and bulb development, but onion temperature tolerance depends on the... link to What Are Pelleted Seeds? Some small seeds are difficult to plant – carrots, lettuce, and onions come to mind. Of course, if the temperature is too high or too low, lettuce seeds will fail to germinate. Regulating the temperature is another good way to improve the health of the plant. For example, lettuce seeds can still germinate in soil close that is close to freezing, but it will take several weeks to do so. That is, the plant will start to grow tall and produce flowers, which will eventually produce seeds. To grow onions, you will need the right conditions, including light and temperature. Shade cloth is a mesh material that filters out some of the sunlight to keep plants beneath it cooler. Experts say lettuce is one of the easiest vegetables to grow in your garden. The ideal temperature for growth of lettuce plants is 55 to 65 degrees Fahrenheit (13 to 18 degrees Celsius). Storage temperatures for fruits and vegetables. 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. If direct seeding your lettuce seeds, thin the plants after they reach the seedling stage by pulling out some of the seedlings to leave enough space between the remaining plants. Let's solve your gardening problems, spend more time growing, and get the best harvest every year! In a natural environment cannabis does not thrive submerged in water: it prefers alternate wet/dry climate (which we replicate with the wet dry cycle when growing in soil or coco-perlite) in order to drag oxygen into its root system and thereby into the plant. Does your lettuce need to be protected from frost? Don’t Ever Plant Anything But Heirloom Seeds If you cover the plants with multiple layers, lettuce can survive down to 0 degrees Fahrenheit or -18 degrees Celsius. The ideal soil temperature for germination though, is 70 to 75 F. In cooler temperatures, germination takes longer. The right temperature is anywhere from 60 to 70 degrees Fahrenheit. Seed will germinate at temperatures between the minimum soil temperature and the optimum soil temperatures, but the number of days to germination will be greater. The ideal temperature range for lettuce seed germination is 60 to 86 degrees Fahrenheit (16 to 30 degrees Celsius). A cloche is a clear plastic or glass cover used to protect plants from cold, pests, and wind. If the temperature becomes too warm or too cool for lettuce plants to grow well outside, they can be moved indoors permanently as long as they have enough light. You can harvest non-damage parts by cutting away brown areas and edges that are frost damaged and save just the leaf parts that are uninjured and your plant will continue to grow. Temperatures above that point quickly facilitate bolting. At night, on the other hand, you need to keep the temperature at about 50 to 60 degrees Celsius. This makes the leaves inedible to anyone with taste buds. Space these half-circles a couple of feet apart in a row and you can cover them with a row cover, giving you a miniature “hoop house”. He holds a Bachelor of Arts in history from McGill University, a Master of Arts in history from Central European University and a diploma in journalism from Concordia University. Here are some types of heat-tolerant lettuce from Johnny’s Selected Seeds: Any lettuce that gets partial shade during the hottest part of the day will take longer to bolt. To grow lettuce in hot climates, you will need a way to keep the lettuce a bit cooler. According the North Carolina State University Extension, lettuce will start to bolt (flower and make seeds) at daytime temperatures of 70 to 80 degrees Fahrenheit (21 to 27 degrees Celsius). If so, please share it with someone who can use the information. I hope you found this article helpful. If direct seeding, scatter the lettuce seeds lightly and evenly over a moist, but not soaking wet, soil surface. Then, plant lettuce below the trellis. Enjoy! Water and light are fundamental to the process of lettuce seed germination. You can make a cloche out of a clear plastic bottle by cutting out the bottom and using the cap on top as a vent. Most lettuce varieties germinate well in the range of 10 to 15 degrees Celsius making them an excellent winter crop for gardeners in temperate areas. Lettuce is a cool-season crop that prefers temperatures of 55 to 65 °F for optimum growth. ... Are Onions Heat Tolerant? learn more about Magenta lettuce from Johnny’s Selected Seeds. (3 Things To Know), link to Are Onions Heat Tolerant? The ideal temperature for growth of lettuce plants is 55 to 65 degrees Fahrenheit (13 to 18 degrees Celsius). Although lettuce can survive a hard frost, this assumes that the plant has proper conditioning. Lettuce is a cool weather crop, so it prefers cooler temperatures for its growth. The first step is to choose lettuce that will work with you to resist bolting in the heat, so we’ll start with heat-tolerant lettuce varieties. Plants with one or two true leaves transplant best. Thin to one or two plants per pot. learn more about Muir lettuce from Johnny’s Selected Seeds. Ideal Temperature for Lettuce to Grow. When the weather gets warmer, lettuce will start to “bolt” or go to seed. You can learn more about lean-to trellises and other designs in my article here. Finally, keep harvesting your lettuce as soon as the leaves are ready (or even when they are still a bit small!) All lettuce varieties are considered cool-season vegetables. learn more about Winter Density lettuce from Johnny’s Selected Seeds. Conditioning means that the plant has had time to grow accustomed to cooler temperatures, instead of being subjected to extreme cold all at once. As the tomato plants grow, they will provide some shade for the lettuce. Lettuce. During germination, the first root and shoot of lettuce emerge from the seed and move downward and upward, respectively. Advisers at the University of Illinois Extension say the best planting temperature is fifteen degrees Celsius. Choose a spot that receives a minimum of four to six hours of direct, full sunlight each day. learn more about cloches in my article here. Now you know the ideal temperature ranges for lettuce germination and growth. Not all seeds germinate and lead to plants. Lettuce thrives in the cool spring season so it requires planting in early spring once soil temperatures are above 60 degrees Fahrenheit. (The upper temperature limit to grow heading lettuces is 28°C/83F) One way to use row covers is to first install supports along a row and then drape the row cover over the supports. You would need to drape a frost blanket or piece of row cover over the cloche to insulate the plant. (3 Things To Know). We used the following techniques to successfully grow lettuce … Best Germination Temp: Best Night Growing Temp: Best Day Growing Temp: Geraniums: 75°F: 50-60°F: 65-75°F: Hydrangeas: Best from cuttings: 60°F: 70°F: Beets: 50-85°F: NA: 60-65°F: Carrots: 50-85°F: NA: 40-85°F: Lettuce: 65-75°F: 60-70°F: 60-70°F A row cover is a piece of fabric material that protects plants against cold and pests. If you want the lettuce to develop fully grown heads, then leave 10 to 12 inches between the seedlings. Shade cloth still allows some light to get through, which means that your lettuce will still be able to grow. based on information from the University of California Extension. I don't know of any plants that die just because it's 40° C. (104° F.) So, what is the best temperature for growing lettuce? That said, when growing lettuce hydroponically you should ensure that the day temperatures range between 20 and 23 degrees Celsius and never at any point exceeding 25 degrees Celsius. For the best results, keep the temperature around 55° Fahrenheit (12.7° Celsius) at night and around 75° Fahrenheit (23.8° Celsius) during the day. Lettuce is a crop that grows better in a cooler environment. According to the Michigan State University Extension, lettuce is a plant that is hardy to hard frost. Lettuce seed will germinate at 35°F, but optimum germination is 70 to 75°F. You can also make a cloche out of wire (such as chicken or rabbit wire), although this will not provide cold protection by itself. Lettuce seeds are small, so … The table below summarizes the temperature ranges for lettuce growth. Shade cloth is another method you can use to keep lettuce cooler. In fact, according to the Texas A&M University Extension, lettuce can even survive a frost or hard freeze, as long as the cold does not come suddenly after warm weather. Than later to avoid a bitter lettuce flavor it will bolt ( produce seeds and bitter! 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