It’s incredibly simple. Consistently moist soil makes for fast growing, happy lettuce. The Romans likewise claimed that it increased sexual potency. If you are planting in pots or containers, this process is a breeze. A couple of weeks later, direct sow another batch. Academic Calendar; College Documentation The hot summer heat tends to wilt and bolt lettuce. [52] A 2007 study determined that the vacuum cooling method, especially prevalent in the California lettuce industry, increased the uptake and survival rates of E. coli O157:H7. [55] This narcotic effect is a property of two sesquiterpene lactones which are found in the white liquid (latex) in the stems of lettuce,[30] called lactucarium or "lettuce opium". [43] Herbicides are often used to control weeds in commercial production. [11] The consumption of lettuce in China developed differently from in Western countries, due to health risks and cultural aversion to eating raw leaves. Lettuce flowers more quickly in hot temperatures, while freezing temperatures cause slower growth and sometimes damage to outer leaves. But what happens when temperatures dip toward the freezing mark? Individual plants require very little space, basic maintenance, and you can harvest leaves as needed once they reach a useable size. Lettuce, annual leaf vegetable of the aster family. Do not let seeds dry out until they germinate. integrata and L. scariola var. Depending on how much space you have, in combination with succession planting, this will lead to near-constant harvests once your seedlings take off. Optimal soil pH is between 5.8 and 6.5 for lettuces. [27], Western Europe and North America were the original major markets for large-scale lettuce production. If you struggle to grow crops, you should get along well with growing lettuce. The plant was thought to help the god "perform the sexual act untiringly. "[23] Its use in religious ceremonies resulted in the creation of many images in tombs and wall paintings. Choose the right variety for your needs and you won’t be disappointed. ALL RIGHTS RESERVED. See our TOS for more details. The plants can be spaced much closer together in the garden (4-6 inches (10-15 cm.)) Lactuca sativa is a member of the Lactuca (lettuce) genus and the Asteraceae (sunflower or aster) family. [40] Mammals, including rabbits and groundhogs, also eat the plants. [10] This word has become the genus name, while sativa (meaning "sown" or "cultivated") was added to create the species name. If your goal is to grow leaf lettuce throughout the summer, choose heat tolerant varieties. [24][25] Between the late 16th century and the early 18th century, many varieties were developed in Europe, particularly Holland. One rule of thumb for row planting leaf lettuce is 10 plants per foot. Thin seedlings out when they’re big enough to handle and keep the compost moist. Plant calendula away from your lettuce rows to attract slugs away from your lettuce. Iceberg/Crisphead – The most popular type in the United States, it is very heat-sensitive and was originally adapted for growth in the northern United States. [56] Folk medicine has also claimed it as a treatment for pain, rheumatism, tension and nervousness, coughs and insanity; scientific evidence of these benefits in humans has not been found. Optimal soil pH is between 5.8 and 6.5 for lettuces. Seeds can be purchased from True Leaf Market. However, when newly harvested lettuce seed is stored cryogenically, this life increases to a half-life of 500 years for vaporized nitrogen and 3,400 years for liquid nitrogen; this advantage is lost if seeds are not frozen promptly after harvesting.[35]. Although this trait can be a problem to home gardeners who attempt to save seeds, biologists have used it to broaden the gene pool of cultivated lettuce varieties. Cover with a very thin layer of compost or vermiculite. Pale to white lettuce, such as the centers in some iceberg lettuce, contain few nutrients.[18]. [10] Lettuce was considered a sacred plant of the reproduction god Min, and it was carried during his festivals and placed near his images. Not only have I harvested several salads from my lettuce crop but have many more leaves to harvest in the coming weeks. Get seeds now from True Leaf Market. Don’t forget to harden seedlings off before transplanting them into the garden. Once weeds begin to appear, lightly cultivate the soil so as to uproot the weeds, but not so heavily that new weed seeds are brought to the soil’s surface and given a chance to germinate. As described around 50 AD, lettuce leaves were often cooked and served by the Romans with an oil-and-vinegar dressing; however, smaller leaves were sometimes eaten raw. Outbreaks Associated with Fresh and Fresh-Cut Produce. You’ll love the pale green, tender leaves. Books published in the mid-18th and early 19th centuries describe several varieties found in gardens today. [10] Today, the majority of lettuce is grown for its leaves, although one type is grown for its stem and one for its seeds, which are made into an oil. Sow seeds every few weeks to keep an everlasting crop coming on all year. Each fruit contains one seed, which can be white, yellow, gray or brown depending on the variety of lettuce. [10], Lettuce appears in many medieval writings, especially as a medicinal herb. [41] Crowding lettuce tends to attract pests and diseases. ♦Please Note: add this information to your Gardening Journal. In addition to its main use as a leafy green, it has also gathered religious and medicinal signific… [46], In the early 21st century, bagged salad products increased in the lettuce market, especially in the US where innovative packaging and shipping methods prolonged freshness. This year I planted several red leaf lettuce plants from seed and have been blown away by the spectacular results. This method dramatically reduces the presence of weeds. Nitrogen and water interactions in subsurface trickle-irrigated leaf lettuce: I. than head lettuce, meaning no thinning needed and garden space is maximized. If possible, water in the morning so plants have a chance to dry off during the course of the day. sativa,[1] L. scariola var. Seeds are available from True Leaf Market. Leaf lettuce refers to varieties that don’t produce any type of head. Similarly, there are some varieties that tolerate frosts better than others. Lettuce spaced farther apart receives more sunlight, which improves color and nutrient quantities in the leaves. Direct sow another batch of seeds in the garden in a sunny location as soon as the soil is workable. By the late 1900s, Asia, South America, Australia and Africa became more substantial markets. [2] L. sativa also has many identified taxonomic groups, subspecies and varieties, which delineate the various cultivar groups of domesticated lettuce.