Beginner’s Guide to Growing Lettuce in Containers

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It is not a secret that the most widely used vegetable in the world is lettuce. The most popular salad, Caesar’s, has lettuce as its main ingredient. That’s why it is safe to say lettuce can be a great green to grow. Whether it is for your consumption or selling, it is certainly worth learning how to grow it yourself. But we’re not interested in growing lettuce the usual way. Instead, you’ll be growing lettuce in containers, a slightly more challenging yet more satisfactory way to grow lettuce.

This method is not rocket science, though. We wanted to make it as easy to understand as possible, so we assembled a comprehensive beginner’s guide with everything there’s to know about it. So, want to learn how to start growing your lettuce in pots? Then keep reading!

When to Grow Lettuce?

growing lettuce in containers

Most people think lettuce is an easy-to-grow vegetable. And while that’s partly true, you should be aware of certain aspects regarding its growth seasons. Why? Because lettuce requires a specific temperature to thrive. And that means anything lower than 75-degrees Fahrenheit is ideal, but anything higher can be disastrous. For example, lettuce doesn’t grow in winter as frosts can be damaging to the leaves. What’s the best season then? It is early spring. After the last frost, you’re ready to plant lettuce. But if you live in a warm area, then fall would be your best bet. However, this is only if you are genuinely planting in a warm place. Otherwise, you will expose the lettuce to the dangers of winter. 

Should You Use Seeds or Seedlings?

You can grow lettuce as a transplant or directly from seed. Of course, the process is a bit different. For example, transplanting requires little effort. You can buy the sprout and transplant it whenever you want on a container. But you’ll have to pick the type of lettuce available in seedlings (which limits variety), and it can be somewhat expensive. 

In contrast, growing from seeds is a lot of work. But it comes at half the price, and with the ability to pick the seed you prefer. You won’t be stuck with whatever the plant nursery has available. More importantly, you’ll be able to enjoy the process from the actual start. In short, it’s all up to you. Go for what feels more fitting for your needs and demands. 

What Do You Need to Grow Lettuce?

Whether it is in seeds or seedlings, you’ll want to know what factors matter the most when growing lettuce. Below, we explain some of those to save you some time and effort in the process.

  • Enough Space

growing lettuce in containers

Few things matter more when growing lettuce than ensuring ideal space. Even if you’re growing them in small containers, you’ll have to ensure they have enough space to thrive. Luckily, lettuce is not a space-driven plant. Meaning, they need about 6 inches of free space around to grow. The largest types of lettuce typically need above twice or thrice that (up to 18 inches). But as little as 4 inches should be enough for most. A small pot should suffice. 

  • Proper Sun Exposure

While lettuce is known as a cold-temperature veggie, it is also a sun-starving plant. Especially in the coldest places, it will need enough sun to thrive. That’s why lettuce mostly grows in areas where it can receive constant sun in the morning and late afternoon. In midday, where the sun is scorching hot, it’s better to place it under shade. 

  • Winter-Like Temperature

growing lettuce in containers

As explained before, lettuce loves cold environments. Most lettuce types will grow bolt, bitter up, or not grow at all with temperatures higher than 75 degrees Fahrenheit. If it is exposed to higher temps than this, it will produce seed prematurely and become brown, causing a bitter taste. To prevent that, ensure the temperature is ideal. Otherwise, keep the plant watered continuously.

  • Constant Watering

When growing in small containers, it is easy to keep moisture flowing. But even then, it is ideal to do it right. You must prevent the water from flowing out too fast. And it would help if you also controlled the moisture from over-flowing the pot, causing rot. Generally, watering twice a day is more than enough for lettuce. Thrice a day if you leave in warm environments. 

  • Fertile Soil

growing lettuce in containers

Potting soil with tons of organic matter, well-drained, and with the right pH. That’s enough to grow lettuce. We recommend well-composted soil with peat, loamy that doesn’t hold much water, and a pH between 6 and 7. If you want to add some manure to the mix, then that also works. Just be sure it drains well to prevent any over-moistening that causes rot. 

  • A Quality Fertilizer

Even though lettuce often needs little to no food to grow (well-composted soil is enough), you can always use fertilizer to boost the process. Fertilizer helps to grow them more significant, healthier, and, more importantly, faster. Generally, a 10-10-10 mix of fertilizer should be enough. Applying it twice within the growing periods should get you an ideal growth. 

  • No Weeds Around

growing lettuce in containers

Lettuce is a somewhat resistant plant. But if weed overgrows the lettuce, then it’s likely to shy away and not grow at all. To prevent that, you’ll need to weed out the area consistently. If you’re growing on containers, then this is even more important. 

  • Eliminate Pests & Diseases

Pests are the number one enemy of any plant. And when it comes to lettuce, this is even more important. Due to the highly edible composition of this veggie, pests are more likely to seek it. The most common among these pests are aphids. They’re super small and hard to get rid of. Even worse, they are green, so they’re tricky to spot. Slugs and snails are also typical and hard to remove. 

The best way to prevent any of these pests is to use insecticidal soap or eggshells. Pesticides also work, but we don’t recommend it if you’re growing them on pots for health reasons. Another solution is to grow them alongside other pest-repelling plants like basil, coriander, mint, or even lavender. However, this can be a bit difficult in a container – so growing them closer can be worth a try. 

How to Grow Lettuce in 8 Steps?

With all the info necessary to start growing lettuce in containers, you’re ready t get your hands dirty. It’s now time to put on the gloves and prepare the supplies. Here’s what you need to do next: 

1. Choose the Ideal Type of Lettuce

First and foremost, make sure you have the right type of lettuce. It’s about picking a kind of lettuce that thrives in the area where you’re living and offers the type of leaf you’re looking for. To make it easier to pick, we’ve assembled a quick list of these lettuces with some info about each: 

  • Celtuce – Looks like celery and tastes a bit sweeter than typical lettuce. Its stem is crunchy and grows in warm environments. This one is hard to grow on pots.

How to Grow Lettuce

  • Butterhead – Boasts a milder taste than other lettuces while still having a loosehead. It is easy to prepare and thrives in cold areas. You can grow it quickly in containers.

How to Grow Lettuce 

  • Iceberg – The classic green ball, also known as crisphead lettuce, is available in most supermarkets. It is a crunchy and long-lasting species. Also, the taste is typically mild, so it works well on salads. It’s hard to grow on containers, though. 

How to Grow Lettuce

  • Loose Leaf – Also known as the hydroponic lettuce (as it is often used in hydroponic gardens), it is an excellent container growing choice. The lettuce is typically small with curly leaves with a sweet taste. 

How to Grow Lettuce

  • Red Leaf – An alternative to loose-leaf, but this one has a slightly more acidic taste. People use it to give a more veggie flavor to salads. It works well on small containers and hydroponic gardens.

How to Grow Lettuce

  • Romaine – The leaves start in the center and grow upward, making it easy to prepare. These leaves are typically super-crisp and tasty. It is also the go-to option for Caesar’s salad. Yet, it requires a bit of upward space. 

growing lettuce in containers

As you can see, not all types of lettuce will thrive on containers. You must be careful when picking. Generally, we recommend loose leaf, romaine, and butterhead as the best options. But you can still try your luck with other types with the right container.

2. Pick the Ideal Container

With the lettuce species ready, proceed to pick a container that gets the job done. Like explained, you’ll need a 6-inch container in diameter and at least the same amount in depth. For broad types of lettuce, go for pots of no less than 12 inches in diameter. They may also work at 6-inch depth with no problem, but try to go a little deeper if possible. As for the materials of the containers, it doesn’t matter much. We typically recommend plastic for its lightness and ease of use. Clay can also be helpful to keep the soil dry. Apart from that, be sure the containers come with sufficiently large draining holes. Otherwise, the soil will get overly-moist and cause root rot. 

3. Starting Seeds Indoors

growing lettuce in containers

If you decide to grow seeds, then you can proceed to plant them in the pots. Sure enough, you’ll have to start by pouring the soil first. It’s recommended to use a seed-starting mix if you’re doing it from the very beginning. Also, try adding enough fertilizer to the mix. You should fill the pots at least 2 weeks before planting the seeds to let the soil establish. Once you have pots with soil ready, add the fertilizer and plant the seeds. They should be at no more than 0.25 or 1/4 inches deep. 

4. Water Consistently Until Germination

With the seeds on the containers, it is time to let them grow. But for proper growth, you’ll have to water them consistently. In this seed state, we recommend keeping the soil moist. That means watering twice or thrice a day. The focus is to prevent the soil from warming up while keeping it filled with nutrients. That’s why it is recommended to leave the pots indoors so that the soil can stay soaked. After a week and a half or two, the seeds should start sprouting out of the soil. 

5. Let Them Breathe & Tan

growing lettuce in containers

When the first few leaves start coming out, you should then place the pots under direct sun exposure. If you can’t ensure proper sun, then leave them under grow lights. If the pots are under the sun, the soil will start to dry faster. It would help if you kept watering consistently in that case. 

Another essential part of the growing process is air. Lettuce needs proper air circulation. You should leave it outdoors if possible. Otherwise, ensure an ideal atmosphere around with fans. To do all of this, you can always bring the seedlings outdoors for 20 minutes a few times a day. That should be enough to ensure proper growth. 

6. Transplant the Lettuce 

Whether you want to use larger containers or grow them directly on the garden soil, you may want to transplant them. Similarly, if you bought the seedling lettuce instead of seeds, this will be a necessary step.

This is a fun part, though. You’ll need a larger container following our above explanation. At the same time, you’ll need heavily composted and fertilized soil. If you’re transplanting directly on the soil, make sure the seedlings have at least 12 inches of space around to grow. On pots, make sure they’re larger than 10 inches in diameter. Transplanting is mostly about digging a small hole and placing the seedling in. Be sure to grab the sprout gently, especially the roots. Once you’ve transplanted them this way, you should water them. Add some fertilizer and start keeping the soil wet. Watering twice a day should be enough.

7. Harvest the Lettuce

growing lettuce in containers

After transplanting, you will see how lettuce will start growing at an accelerated pace. Most lettuce types grow within 3 weeks so that you can harvest them. When it’s time, you should grab a sharp knife and cut them directly with shears. Do it from the edge between the roots under the soil and the leaves that sprout out. Try not to cut the stem of the plant but only the part that’s exposed.

Some leafy lettuce types need to be harvested just a bit. For this, you’ll have to harvest individual leaves instead. Otherwise, they may not grow later on. Be aware that some varieties are one-cut. Meaning, you won’t be able to grow them consistently, cutting them and then letting them regrow. Instead, you will only have one harvest from each. But most of them can be transplanted afterward and will still grow further. Typically, they require about a month or two to grow back to the harvesting stage so you can repeat the process.

8. Store the Lettuce

Once you’ve harvested the lettuce heads or leaves, then you’re ready to store them. This process is as simple as it sounds. We recommend looking for a cool area like a refrigerator. But instead of placing them directly, clean them up first. Remove any brown or dark spot that looks like a disease. Don’t forget to use a plastic container or bag. The focus is to prevent contamination from other food in the fridge. 

Some types of lettuce may last up to 3 weeks in the fridge. Others you’ll need to consume within 2 weeks or less. 

Conclusion

See that growing lettuce in containers is not as hard as it seems? It is almost the same process as growing them in direct soil like garden beds or vertical gardensBut because it is easy doesn’t mean you should go at it without paying great attention to what you’re doing. A single mistake like leaving the lettuce way too much time under the sun or not transplanting properly could get you an entire year without harvest. However you proceed, make sure you do it right. If you follow this guide to the letter, that will be a piece of cake.

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