The following 101 on growing lettuce comes courtesy of HOMEGROWN member and Ohio farmer extraordinaire Lucy. (Read more about Lucy and Boulder Belt Eco-Farm.) Thanks so much, Lucy, and please keep the good ideas germinating!
When most people think of lettuce, they think of what they see in the grocery store: iceberg, green leaf, romaine, and perhaps red leaf. But with more than 200 heirloom varieties available from places like Seed Savers and Fedco, there are so many other kinds out there. So why plant boring old green leaf when the sky is the limit? For your home garden, you might consider butterhead/bibb, lollo, oakleaf, and many more. There are speckled lettuces, such as forellenschluss; there are crispheads, such as igloo and red Grenoble; there are red and purple romaines; and so many more. A lettuce patch with many different varieties and colors is one of the most beautiful sights in the spring or fall garden.
WHEN TO PLANT
Lettuce is a cool weather crop and does best planted in the spring and fall, when the daytime high stays below 75F, and nighttime temps hover between 40 and 60F. That said, lettuce can take much colder conditions with some protection, such as a cold frame or a row cover (or, for more advanced growers, a hoop house), which lets you grow into the winter months and get started earlier in late winter/early spring.
Here at Boulder Belt Eco-Farm, we start planting lettuce in mid-March and replant every week or so through the beginning of May. For great lettuce, it’s crucial to plant at least 30 days before the temps get really hot (in southwest Ohio, that’s early June). Otherwise, the plants will get heat stressed and become bitter and usually bolt to seed, as well.
Likewise, you can grow lettuce throughout the summer, as long as your lettuce has ample shade and copious amounts of water. That means hand water morning and night, along with several mistings during the heat of the day. Because lettuce doesn’t really like heat, plants grown in temps above 85F tend to be bitter if allowed to grow to full size. If you want to plant summer lettuce, look for varieties that are described as slow to bolt and that can withstand hot weather. Green varieties do a lot better than red varieties in the heat.
Plant in an area that will get at least five hours a day of good sun—unless you’re growing in summer, in which case you’ll want a cool, well shaded area that gets indirect sun. (You can use a 50 percent shade cloth or shade structures if you’re short on trees or other shade providers.) Just to be clear, lettuce can take full sun in spring and fall but not in the summer.
HOW TO PLANT: STARTING SEEDS INDOORS AND TRANSPLANTING
Start seeds indoors 2 to 3 weeks before you want to transplant them. I use soil blocks, but paper cups or egg cartons filled with a soiless mix will work fine, as will Jiffy pots and similar products. Do not use garden soil to start seeds; you want a mix with no fertilizer in it. You will need grow lights (that is, shop lights outfitted with T-8 bulbs or LED grow lights) that can be hung from the ceiling or a shelf and adjusted as the plants grow. Once the seedlings are 2 to 3 inches tall, they are ready to be hardened off in a cold frame for 3 to 7 days before you transplant them. If you skip the hardening off period, expect to lose 75 percent of your seedlings a day or two after transplanting.
To transplant, you’ll need to have your planting bed ready to go. As for tools, you’ll just need a trowel and a full watering can, since the transplants need a good drink as soon as they go in the ground. To transplant, plunge your trowel into the soil and pull back towards your body. You now have a planting hole. Quickly pop the seedling into the hole and cover it up to the crown (the point where the leaves come out of the plant). Then go on to the next plant. When all the plants are in the ground, water them well. I like to put a soluble kelp product, like Maxi crop, in the water so they get a good feed, are less stressed, and can get on to the job of growing.
The advantages to starting seeds indoors before transplanting outside are that you can get started 3 to 4 weeks earlier and you can space your seedlings correctly when transplanting in order to get as large a head as possible. On our farm, we grow more than 25 different kinds of lettuce, with 250 to 300 plants in a bed, so we generally start all of our lettuce indoors in soil blocks. But that’s for our larger scale operation. Home gardeners shouldn’t stress; sowing outdoors is fine.
Much easier than starting indoors. Rake your seed bed smooth, make a shallow trench in the soil, drop a seed in the trench every 4 to 6 inches, and cover with about 1/8 inch of soil. Do not plant lettuce deeply, as it needs some light to germinate. Water immediately after planting.
HOW MUCH TO PLANT/
Some folks will get a packet of lettuce seed and plant en masse, with no thought to spacing. What those folks end up with is 100 to 150 small heads of lettuce that come in all at once and start to bolt within five days. (If you like bitter vegetables, the lettuce is very edible.) This leaves you stuck trying to consume many pounds of lettuce in a short period of time, which means most of the lettuce is wasted. Such a sad state of affairs doesn’t have to come to pass.
The solution is succession planting, wherein you plant multiple small rounds at one-week intervals. Instead of planting one or two entire rows of lettuce all at once, you plant 1 to 3 feet of lettuce, with plants spaced 6 inches apart. That gives you two heads of lettuce per row foot, letting you really control and lengthen your harvest from one week of way too much lettuce to six weeks of just the right amount.
To get a full head of lettuce, wait 40 to 60 days (the length of time depends on the variety; this information should be on the back of your seed packets), then go out and cut the head below the crown. You don’t want to wait too long, or the lettuce will begin to bolt and get bitter.
WHEN AND HOW TO HARVEST:
You can start to pull individual leaves at around 20 to 25 days, or when the leaves are about 2 inches long. Continue to pull leaves until the plant starts to bolt and develops a flower stalk.
If you want to harvest a full head of lettuce, I don’t recommend pulling off leaves. If, however, you want to harvest baby leaves, I do recommend planting seeds much closer together. In other words, remember that newbie mistake I mentioned up above? Do that: Take a packet of seed (or about 1 tsp), make a shallow trench about 2 feet long, pour the seed into the trench, cover shallowly, and water. You will get hundreds of closely planted lettuce plants that you can cut or pull leaves from. This method will yield enough lettuce for a decent-sized salad every day for about a week to 10 days. As with head lettuce, you can succession plant using this method, and you’ll have baby salad greens for months.
PESTS AND PROBLEMS
Lettuce has several natural foes and diseases, all of which can be controlled organically through various means. For more on pests, check out the Natural Pest Control 101, and for more on pest, diseases, and lettuce in general, download this PDF from the Cornell Cooperative Extension.
MORE THINGS TO GROW
Got a hankering for green leaf but don’t have a green thumb? Have a lettuce issue that’s coming to a head? Post a question for Lucy or share your own tips below. You can dig up more things to sow early and often in the Fall Planting and Winter Planting 101s, and you can always find more things to plant, grow, make, craft, cook, preserve, and water in the HOMEGROWN 101 library.
Thanks Lucy! The other day I was staring at my raised bed garden with lots of questions, and you've basically answered them all. And now we shall be lettuceless no more, but gain new ground to grow more lettuce! :)
I had an older retired scientist show me a way to germinate and plant lettuce that works incredible with very little work. First buy seeds that have been pelleted (Johhny's Seeds). It makes it possible to handle them without any issues from their size. You take a 540 count, round 1/2 diameter hole, plug try and fill it with a starter soil. Plant your seeds and water for three weeks. Then in the last week, during the day put them outside and harden off. Take a drill (cordless) with a 3/4 inch bit and drill a hole where you want to plant the head. Remove the plug from the tray by pushing it out from the underside with a 1/2" piece of wooden dowel and insert the plug into the hole, push the dirt around it to tighten and wah lah, you have a plant planted. I was able to plant 200 heads per hour and never had one die, except for the deer kill. It really works and very well. I took the plug tray and divided it into three equal parts and started each part one week apart for a spring season. I intend to do the same for fall as well. Good Luck and happy growing! :)
Hi William! This sounds very interesting. Could you perhaps upload these instructions as a "101" and include some pictures so we can better understand this technique? I am a technical person but you lost me at "540 count, round 1/2 diamater hole" and the rest I had trouble conceptualizing. If I had some step-by-step instructions along with some pictures, then I'd really like to try this.
Hi, Chris and William. William, thanks so much for sharing your method of lettuce germination! Like Chris, we'd love to hear more. Unfortunately, we can only create 101s here, from HOMEGROWN's back end, but if William is willing, he could create a new blog post and include photos and more detailed step-by-step instructions there. Fingers crossed he'll be game. We'll keep an eye out for it!
I would love to do a 101. I haven't photoed this process, so as I develop this spring's crop (in the next few weeks) I'll get photos and write a better description of the process. Until then, happy growing! :)
Thanks for the post! One warning about thinning lettuce: When finding the optimal distance between planting seedlings make sure that the spacing is proper to your specific variety. Many websites will state that you need to thin your lettuce 18-24" but if you are planting leaf lettuce, that is not right at all. Read the packages that the seeds came in and they should tell you the proper distance for thinning.
thank u! may i recommend this piece on lighting http://www.ledhorticulture.com/23/
very interesting, I thought - with some useful hints on light distances...