Growing Lettuce in Containers
Growing vegetables at home is a great way to reduce your grocery bill and ensure a steady supply of fresh, nutritious foods. Lettuce is no exception and is an easy-to-grow crop that anyone can grow successfully. Learn everything you need to know about growing lettuce in containers here!
This post contains affiliate links. To view my affiliate disclaimer, click here.
Getting Started with Growing Lettuce
Lettuce is a really popular vegetable that is really easy to grow. Before we get into how exactly you’ll grow lettuce, let’s talk about the plant itself. Understanding the plant can go a long way in helping you to be successful when growing it.
Many crop plants are grown for their fruits. Think tomatoes, cucumbers and watermelons. When you grow these kinds of vegetables, you want to induce them to bloom and produce large amounts of fruits that you can harvest.
Lettuce is different. You’re growing lettuce for the leaves, not the fruit. You’re probably thinking “…so?”
This makes a difference in how you grow lettuce. The fact that you don’t want it to bloom will determine the environment that the lettuce needs to grow in and the nutrients that it needs. You can learn more about plant nutrition here.
It’s also important to realize that lettuce grows quickly and some types can be harvested in less than two months. Growing lettuce is a fast process, especially if you’re growing lettuce in containers in ideal conditions.
Buying Lettuce Plants or Seeds?
This is a question that always comes up. Should you sow seeds or plant seedlings?
In many cases, seeds are the most cost-effective option. There are several good reasons to sow your own seeds. It’s also very simple to start your own seeds at home. If you purchase seeds, not only will you save money, but your options will open up tremendously.
I don’t know about you, but the lettuce seedlings that I’ve seen in my local garden centers are few and far between. In fact, when I have seen them, they are often more expensive than purchasing a ready-to-eat head of lettuce, which defeats the purpose for me.
A quick flip through a seed catalog will show you that there are numerous types of lettuce available if you’re willing to start seeds. Let’s just visualize something for a moment. Are you a fan of the salad bar at Ruby Tuesdays?
If you aren’t, then you’re missing out. If you don’t have a Ruby Tuesdays near you, then you’re missing out. Sorry. They have the best salad bar with so many options. I love that they offer more than one type of lettuce.
Or maybe you’ve been to a restaurant that serves a really good salad with weird lettuce. Many chefs today prefer to make salads with lettuce that has bold color and texture. It stands up on the plate rather than lying flat like traditional iceberg lettuce.
For fans of the textured and colorful lettuce, you’ll most definitely want to grow your lettuce from seeds so that you have plenty of options. For those of you that prefer more traditional types of lettuce like iceberg or romaine, then you’ll still probably want to grow lettuce from seeds just because of the price factor.
It makes much more sense to pay $3.00 for a package of ~40 seeds than it does to pay $3.00 and get two lettuce seedlings. Not to mention the fact that you can purchase prepared lettuce for that much without having to grow it!
Equipment Needed to Grow Lettuce
Growing lettuce in containers is simple. You can easily grow lettuce indoors in pots, growing trays or even miniature hydroponics systems. Growing lettuce using hydroponics and aquaponics is an efficient way of growing lettuce, but it’s not the only way. If you don’t want to invest in an elaborate hydroponics or aquaponics system, try your hand at growing in regular containers or small-scale hydroponics systems.
To grow lettuce, you’ll need:
potting mix (if growing in containers)
a cool location
This really isn’t very different than what you would need to grow other crops, with the exception of a cool location. If you find that growing lettuce isn’t your thing, you can always reuse this equipment to grow other crops, herbs or flowers.
Where to Grow Lettuce
Location is important for growing lettuce. It’s not so much sunlight that matters as much as the temperature of the location. Lettuce is a cool-season crop. This means that you want to grow it when temperatures are cool, not warm.
If you plant lettuce in a space that is warm (>68 degrees F), then you’ll find that your lettuce bolts. Lettuce ‘bolts’ or shoots up and blooms when the weather is warm enough.
A bolted plant will start putting all of its energy and nutrients into flowering and not into the leaves of the plant. This causes the leaves to lose much of their nutritional value since nutrients are being pulled into the flowering parts of the plant.
It also changes the flavor and texture of the leaves. You can eat the leaves of lettuce that has bolted, but it’s not going to taste good. Lettuce that has bolted is usually bitter in flavor. Not good for that large chef salad that you had in mind.
Ideally, the temperature around your lettuce plants should be between 55-65 degrees at night and 65-75 degrees during the day. Lettuce that is exposed to temperatures over 80 degrees Fahrenheit will bolt quickly. You can purchase cultivars that are less likely to bolt, but it’s still a good idea to keep lettuce in a cool location.
Also, limit the amount of direct sunlight that your lettuce gets. Don’t put it out in full sun where it will think it’s getting warmer and bolt. Lettuce can be grown in the shade or under larger crop plants that can provide it shade.
Thinning Lettuce Plants
I mentioned that starting lettuce from seeds is the best way to go. With that being said, lettuce seeds are TINY. You may have a hard time separating them and planting them far enough apart.
Because of that, you’ll need to be able to thin your lettuce plants when the time comes. Lettuce crops don’t take up much real estate vertically, but they do take up considerable space around them. This is especially true if you’re growing lettuce in containers. Heads of lettuce can take up as much as 12″ of space, so you’ll need to plan accordingly.
Thinning lettuce plants is simple. Look over your lettuce seedlings. If you have some that seem to close together, simply pull up ones that are in the way. I like to pull up the smaller seedlings that look less vigorous and leave the stronger-looking plants.
When you purchase seeds, the seed packet should tell you how far apart to space the plants. Use this as a guide to see how far apart your lettuce plants need to be. Some varieties, like Romaine, take up much less space around them than others. Sometimes when you order seeds from a seed company, the information on the seed packet is limited. In this case, you can refer to the seed company’s catalog or website to determine how far apart to space plants.
If you’re interested in thinning out plants and harvesting some lettuce at the same time, check out the video below:
How to grow lettuce
This is the fun part! Lettuce is one of those plants that grows quickly, so it’s fun to watch it grow. It’s an excellent plant to grow with children (or impatient adults) because it’s almost instant satisfaction.
If you’re serious about growing lettuce in containers, then you’ll want to grab a copy of my ebook Vegetable Gardening in Containers. Find out more information or to grab your copy here: Vegetable Gardening in Containers
Not only will you learn how to grow vegetables, but you’ll learn all the ins and outs to get started with a successful container garden EVEN IF YOU HAVE A BROWN THUMB!
Hopefully you’ll start with seeds since they are the most economical choice. Just in case you’re not, I’ll include instructions for planting seedlings as well.
Lettuce plants can be grown in many types of containers and potting media. You don’t necessarily have to grow them in soil, although I would recommend that for beginners since it’s the safest option.
Before you sow your seeds, you need to fill your containers. Put potting mix into your containers. Don’t pack the potting mix down. Instead, fill the container and thoroughly wet the soil. Let the water drain out before doing anything else.
Once your soil has been wetted and drained, you can plant your lettuce. For seeds, simply use your finger to poke a hole to the proper depth (varies with variety of lettuce, but usually 1/4″- 1/2″). Place one seed into the hole and gently cover it. Don’t pack the soil over the seed.
If you’re planting seedlings, you’ll want to change your method slightly. When you’re filling your container, don’t fill it to the top. Fill the container 2/3 of the way full. Wet and drain the soil like you would for planting seeds. Once the soil has drained, place your seedlings in the container on top of the soil. Fill in the space around them with additional soil, making sure to cover the roots completely.
Once the seedlings are nestled in place, give them a good watering. You may notice some spaces where the soil around the plant sinks and exposes the roots. Cover this up with soil as needed.
*Note- You may notice lettuce seeds are pink or another bright color when you open the seed packet. This is due to a colored coating that seed companies put around the seeds. Lettuce seeds are very small, which makes them hard to see and handle. The coating makes it easier to work with them. Some seed coatings are designed to help the germination rate of seeds. In my experience, there isn’t much difference on a small scale between coated seeds or non-coated seeds when it comes to germination. Seeds with coating are much easier to work with though.
Growing in Containers
Lettuce can be grown in many types of containers, including containers that don’t even have soil in them. So how do you know what type of container to use?
Choosing a Container
As a general rule of thumb, lettuce heads will need 6-12″ of space per plant in a container. Some varieties of lettuce, like iceberg or butterhead will take up the most space. Smaller lettuce varieties can be grown around these larger varieties to make the most out of your container space.
Normal flower pots can be used to grow lettuce. Check to make sure that the flower pot has holes in the bottom for drainage. You’ll be watering your lettuce every day and you don’t want excess water sitting in the soil. Too much water can cause root rot.
A window box or raised bed is also a perfect location for growing lettuce. These containers will give you the most space for growing multiple types of lettuce.
Hydroponic gardening involves growing plants in water, without soil. It may sound like a new concept, but it’s been used for thousands of years. In fact, the ancient gardens of Babylon used hydroponics for many plants.
Most commercial lettuce is grown hydroponically in greenhouses because it’s very effective and a clean way to grow lettuce. There’s no soil to get the plants dirty, so harvesting and cleaning the lettuce heads is really simple.
If you’re interested in hydroponic growing, check out this post that will answer your questions about the basics of hydroponics. There are tons of hydroponic systems that you can grow lettuce in. Some of them are designed for intensive greenhouse growing systems, but you can find smaller hydroponic systems. Many of these smaller hydroponics systems can fit on a counter or tabletop.
The soil around your lettuce plants also needs to stay moist to help the plant think that it’s winter. Remember, if your plant thinks that it’s spring or summer, it could bolt and will cause it to be bitter and inedible. Water your lettuce daily. Lettuce leaves don’t mind getting wet, so don’t be shy about watering the entire plant and the soil around it.
Lettuce plants need to think that it’s winter to prevent them from bolting. Even a day or two of warm temperatures will cause lettuce to shoot up and become bitter. For the best outcome, lettuce plants need to be grown with night temperatures between 55-65 degrees F and day temperatures between 65-75 degrees.
If you have an abnormally warm day, you can help prevent bolting by keeping the plant watered. This will cool the plant down and hopefully squash any urges for the plant to bolt. Water the plant itself, thoroughly soaking the leaves to cool the plant off.
Lettuce plants thrive in soil that is rich. Once your seeds have sprouted, you can start fertilizing them. Choose a fertilizer with equal parts of nitrogen, phosphorus and potassium. 10-10-10 fertilizer is an excellent choice for growing lettuce.
Types of Lettuce
There are numerous types of lettuce that you can grow. There are so many colors and textures that you can create a lettuce container that is attractive.
Leaf, romaine, iceberg, butterhead, and frisee are the most popular types of lettuce.
There are three main types of leaf lettuce: red, oak and green. These lettuce varieties don’t create a ‘head’ of lettuce, but instead a clump of tightly grown leaves. Leaf lettuce can be highly textured and vibrantly colored. This is the lettuce that you usually find in a spring lettuce mix. Because leaf lettuce doesn’t make a head, it doesn’t last as long once it’s harvested.
Romaine lettuce creates a head, but instead of a rounded head, it creates an elongated head. You’ve likely seen romaine lettuce in the grocery store. Romaine lettuce is crunchy and is the main lettuce in most Caesar salads. You can expect romaine lettuce to last a little longer in the refrigerator since it creates a head.
Iceberg lettuce is the classic lettuce variety. It’s super crunchy and can keep for up to two weeks in a refrigerator. Iceberg lettuce makes a tightly developed head of leaves. This lettuce doesn’t pack much punch when it comes to flavor, but the high water content makes it an excellent low-calorie variety.
Butterhead lettuce falls somewhere in between iceberg and leaf lettuce when it comes to appearance. These leafy varieties create more of a head than leaf lettuce. There are two main types of butterhead lettuce: Boston and Bibb. Butterhead lettuce is somewhere in between crunchy and tender, with colorful leaves that are tightly packed and fluffy.
Frisee lettuce is fun. The leaves of frisee are very curly and usually vibrantly green. This lettuce will add tons of texture to a salad. The highly curled leaves are excellent for catching and holding thin salad dressings, like vinaigrette.
You may also see kale, spinach, radicchio and endives occasionally referred to as lettuce types. They can be grown along with lettuce in the same conditions and can be tossed into salads for extra flavor, color, texture and nutrients.
Most lettuce varieties are one-cut varieties. This means that once the head is ready to be harvested, you’ll cut it off and then replant in order to get more. Some of the leafy varieties can be cut multiple times since there isn’t a head to remove.
In order to get a steady supply of lettuce, stagger your plantings. Don’t plant all of your seeds at once. Instead, plant a few the first week, then a week later plant a few more. Planting seeds weekly will make sure that you don’t run out of lettuce.
To harvest heads of lettuce, you need a sharp knife. Find the bottom of the head where all of the leaves come together into the stem. Using your knife, cut through the stem just below the head of lettuce. Cutting the stem and not the head itself will help hold the head together and help extend the shelf life of the lettuce.
Leafy lettuce can be harvested a little at a time. Use a sharp knife or scissors to remove individual leaves from leafy lettuce.
Once harvested, you can clean it up and eat it right away. Lettuce that you’re not eating right away can be stored in the refrigerator. Heads of lettuce can be stored in containers with a little bit of water in the bottom to help prevent the plant from wilting. Leafy lettuce or lettuce that has been cut up will wilt quicker, so plan on using it within a few days of harvesting.