Your Guide to Growing Lettuce in Containers
Containers Allow Freedom to Choose How and When to Grow Lettuce
For years I struggled with how and when to grow lettuce. So, I decided to try growing lettuce in containers. For three years now, we’ve enjoyed more lettuce than I could have ever imagined. Growing lettuce in containers makes it easy to weed, control disease and harvest seeds.
A Little History of Lettuce
Records of growing lettuce date back to at least 500 B.C. It was introduced here in America by Columbus. While there are many magnificent lettuce types, there are five basic groups: butterhead, celtuce, crisphead, looseleaf, and romaine.
Butterhead – They make a loose leafy head. The delicate, delicious flavor is divine.
Celtuce – Makes a stem and not much leaf, like celery. Grown for its stems instead of its leaf.
Crisphead – Probably the most recognized is Iceberg. These have large firm heads. These have less color, fewer vitamins and minerals, and a flat taste. They are perfect for industrial production, but are the hardest to grow in the home garden. They take twice as long to mature as leaf lettuce. Head lettuce can take 80 to 95 days and all those days have to be cool.
Looseleaf – These are the easiest to grow. There are a few varieties that are hot weather hardy. My favorite of these is Oakleaf and Deer Tongue. Yep, they’re named by the way they look. Loose leaf lettuce has a stronger taste and may require some adjusting to. It matures in 40 to 45 days.
Romaine – Comes in a wide variety of choices. Romaine spreads out from a tight center instead of forming a ball or remaining loosely disconnected. It can tolerate some heat, but not as much as the leaf lettuce. They take 70 to 85 days to mature.
Lettuce is a cool-weather crop. Your planting zone will determine if it is a spring, winter, or spring and winter crop for you. For spring planting, sow as soon as the soil is workable and the danger of hard frost has passed. For winter planting, plant when your soil temperature does not exceed 75°. Lettuce does not like to germinate in soil warmer than this. Be sure that your plants are shaded from long exposure to the midday sun.
Choosing your Container
First, you have to determine the size of your container and how much lettuce you want to grow. You can grow a few different varieties in a 10-12 inch pot. Remember that lettuce is mostly water so be certain that your soil is consistently moist, but not wet. Lettuce cannot tolerate wet roots, so be certain that your container drains well.
Growing lettuce in a container is about the size of the container, the soil, and the moisture. Whatever soil medium you choose, be certain it is loose and well worked. We use a 2:1:2 mixture of sand, composted soil, and dirt from the chicken yard.
How to Plant in a Container
There are two prescribed methods for starting your lettuce. I have used both and had success both ways. They are growing seedlings indoors for transplanting or direct sowing.
To start transplants for growing lettuce in a container, sow the seeds in your prepared trays. Lightly cover with no more than 1/4 inch of soil. I tend to scatter my seeds across the seed tray and brush dirt over them. Leave them where they get plenty of light. Keep the seedbed moistened until they sprout. Then water as needed.
Some seed trays come with lids, but I’ve lost mine over time. I cover mine with painters plastic. This keeps the rain off of them, gives them a greenhouse like effect, and keeps the moisture level just right. All this while letting in the light!
When they have developed two true leaves, I transplant them to my containers. Place transplants in your container by making a 1-2 inch hole. Place your transplant in the hole, replace the soil, and water them. Be careful not to crush the roots. Depending on what else is happening on the farm, I like this method.
Direct sowing into your prepared container requires you to do some thinning. Since the thinnings are tasty treats, this is not a problem. To direct sow your seed, place the seed 1/4 to 1/2 half inch deep in moistened soil and cover.
You can sow your seeds 4 to 6 inches apart. Remember to not let the seedbed dry out.
When growing lettuce in containers, remember that loose leaf and romaine need less space than head or stalk lettuces. A general rule of thumb is to set transplants one every 4-6 inches. Don’t worry about being exact, just be sure they have plenty of room. A one-gallon container can hold 2-3 plants depending on the variety you choose.
You may want to leave a nice edge around the edge for fertilizing, watering, and mulching. I don’t mulch my lettuce, but I know people who do. Learning how to lay mulch and applying it correctly does help keep the soil evenly moist when growing lettuce in a container.
Lettuce Growing Tips
1. Make sure your plants have adequate space.
2. Maintain adequate moisture, but not wet.
3. Ensure adequate drainage.
4. Do not fertilize unless you feel your soil is not supplying what your plants need. Your lettuce needs to be eight to 10 weeks old before you fertilize. It’s shallow roots make it susceptible to root burn.
5. When thinning, don’t disturb the roots of neighboring plants.
6. To keep your harvest going, replant at two-week intervals. This is called succession planting.
7. Harvest lettuce in the early morning. Exposure to the sun and heat can wilt tender leaves. Cutting them when they are in distress can damage the plant. The plants (not head lettuces) will continue to replace leaves you eat until bolting.
8. After harvesting, wash your lettuce and allow to air dry. Store in the refrigerator. I wrap mine in a damp dish towel and place in a vegetable bag or a plastic bag. It keeps for at least a week.
Bolting is the sudden maturing of the lettuce. It rushes to produce seed. Bolting is usually triggered by increased temperature and longer days with the coming of summer. Bolting causes the lettuce to become bitter tasting. Different lettuce types are more resistant to bolt than others.
While you can’t prevent bolting, you can prolong your season. Plant as early in the spring as you can, whether indoors or out. Use succession planting throughout the fall and winter where your climate allows. Be sure that your lettuce is protected from mid-morning to late evening direct sunlight.
Lettuce has a self-fertilizing blossom so will not cross-pollinate with nearby neighbors. Just so you know, there is a risk of cross-pollinating with wild varieties of lettuce like the dandelion, if you allow your plants to bolt. Remember bolting will make the leaves bitter. You’ll see the straight stalk shoot up. This will produce beautiful yellow flowers that will mature into seeds.
Once the flowers produce their seeds, you can place a paper bag over the stalk and shake it well. By doing this every few days, the mature seeds are gathered and the immature seeds remain on the plant until they’re ready. You can stop collecting seeds when you have all you want, but pull the plants. Given the right circumstance, you’ll have volunteers.
Another method is to allow about half of the seeds to develop then remove the entire plant. You can place it on a drop cloth are in a bucket. This will allow you to catch the seeds that fall and the remaining seeds should go ahead and reach maturity. A 1/8 inch screen works well to separate the seeds from plant debris. When stored in a cool dry place, lettuce seeds will generally remain viable for up to three years.
Although arugula is not a true lettuce, it is becoming a pretty popular salad green. Many are successful growing arugula from seed. If you’re like me, one of your favorite fall greens is cabbage. It’s good to learn how to grow cabbage. I have also grown cabbage in containers and it does quite well.
I like growing lettuce in containers. It frees up garden space and makes growing lettuce easier. It’s an excellent way for anyone with limited space to grow different lettuce types.
Do you enjoy growing lettuce in containers? As my grandfather taught me, “There’s as many ways of gettin’ a farm job done as there are farmers. Ya gotta be willing to listen, help, and learn from ’em, even if it’s just to see what not to do.” So feel free to share your tips and experience in the comments below. You can always reach me personally with questions or concerns by using the Contact Me page.
Safe and Happy Journey,
Rhonda and The Pack