Lettuce is one of the few food crops you can grow at home year-round, so you can have it on hand at all times.
Spring can be a good time to grow vegetables outdoors, but at any time of the year, lettuce is easy to grow indoors. As with growing herbs indoors, you just need to ensure proper indoor growing conditions and be on your way to harvesting fresh lettuce from the comfort of your own home.
Whether you want to grow bitter or light leaves, tender or crispy, some salads are better for indoor growing than others. Use this guide to find the best indoor lettuce as well as simple steps to grow indoor lettuce at any time of year.
The Best Lettuce Varieties for Indoor Growing
- “Green oak leaves”: The green and green leaves of this loose-leaved salad are very easy to grow and tend to have a mild and crunchy taste.
- “Red oak leaves”: This loose-leaved variety, with its dark red leaves and slightly bitter taste, is ideal for seasoning salads.
- Children’s leaf varieties such as “Red Sails”, “Refugio”, “Parris Island”, “Defender” can be harvested in the early stages of growth.
A step-by-step guide to indoor lettuce cultivation
1. Choose your indoor growing location
Find the sunniest places in your home that provide at least six hours of bright sunlight per day. Choosing the area near the south-facing window usually provides the best amount of sunlight for indoor lettuce growing.
It should be noted that lettuce plants should not be exposed to direct sunlight in the hottest part of the summer sun, otherwise they will be burned. If you don’t have enough natural light, invest in grow lights designed specifically for indoor gardening.
2. Change the growing conditions
Lettuce prefers cooler temperatures, so you need to make sure the space where the seeds germinate is between 55°F and 65°F. Seedlings should be planted between 50°F and 60°F to prevent twisting (flowering). Due to the warm growing conditions, the plant can shift early, which makes the taste of the leaves unpleasantly bitter.
It’s also best to increase humidity around plants, as the air in your home is usually drier than in most outdoor environments. Help prevent indoor lettuce plant diseases by increasing air circulation by using a small fan that gently moves moist air around the plants.
3. Choose a suitable container
Lettuce has a shallow root system, so it grows best in a medium-sized container. A containerized lettuce garden works better in plastic than clay pots because clay dries the soil mixture faster than plastic.
An elongated container is great for a short row of salads. If there are no drainage holes in the tank, make a few small holes in the ground before planting.
4. Use the pot mix for vegetables
Plant lettuce seeds in fresh pot mixture intended for growing vegetables. This mixture should be drained properly and only a few fertilizers, if any.
You can also mix potting soil in equal proportions in bags, sterile compost, perlite and coarse sand. Starting lettuce seeds in a fresh, potted mixture helps reduce diseases, pests and weeds.
5. Buy lettuce seeds or seedlings
Lettuce seeds can be purchased year-round or seedlings in cell packs from the garden center from spring to early summer.
Don’t forget to look for lettuce varieties with loose leaves, as these are more suitable for indoor growing than lettuce varieties.
6. Sow lettuce seeds at a shallow depth
Fill the pot with soil so that there is about an inch of distance between the top of the tank and the bottom. Sow the seeds on the ground and make sure they spread instead of clumping.
Lettuce seeds actually need light to germinate, so either leave them on the ground or cover the seeds very little with potting soil.
7. Water the seeds with a misty bottle
Spray the seeds daily with water to keep the soil moist but not soak it. Watering the seeds directly with watering can cause the seeds to sink deeper into the soil or be washed onto one side of the pot. Depending on the type of lettuce, you can see the appearance of plants in about a week or two.
8. Water lettuce seedlings well
After the plants appear, continue to keep the soil moist, but do not soak it. Avoid overwatering by following best practices for watering houseplants. Prevent root rot by removing excess water that can accumulate under the pot.
9. Thin weaker seedlings
If multiple seedlings germinate close together, remove weaker seedlings so that stronger seedlings have more space to reach their full potential.
Check the seed packaging for the ripe size of the lettuce varieties and be sure to place them accordingly.
10. Harvest lettuce at any time
Cut the lettuce leaves as they grow to the desired size. If you prefer small lettuce leaves, cut them when they are about 6 inches long.
Avoid cutting the inner leaves of each of the lettuce groups so that the immature growth develops into larger leaves for later harvest.