How To Grow Lettuce Indoors

Grow lettuce indoors? The idea might surprise you. Maybe you don’t have space for an outdoor garden or you want a fresh supply of veggies on hand during the winter. Can lettuce successfully be harvested from pots? The answer is yes.

If you don’t have an outdoor growing space or you prefer not to work with winter growing methods, you can successfully plant and harvest lettuce in a pot from your home or in another space (more on that in a minute).

The first time we grew lettuce in our basement we were pleasantly surprised when we succeeded. We were just doing a trial run to see how well it would work because the cold temperatures of late fall and the coming winter were almost upon us.

Even though lettuce can grow under cover outdoors in the cold months, it takes at least an extra 3 to 5 weeks more to mature even in a hoop house like we have. We needed something faster than that and it worked!

In this post, we share tips on exactly how you can do it with a few simple steps and minimal equipment.

Find a Growing Space

To grow lettuce indoors effectively, you’ll need a grow light. We recommend this type of LED light from HTG Supply.

If you have an unheated or cool section of basement or an open space in a shed or other outbuilding, that will work well for you too. Temperatures for lettuce growth run between 50 and 70 degrees with ideal being 60 to 65.

Use a 1 or 2 gallon plastic pots. We recommend 2 gallon for each plant if you want to grow it to full maturity. We found the square ones are best but round works too if that is all you have. You can find these on Amazon or buy used from Ebay. They work well for us.

Soil

To grow the best lettuce indoors, use a good organic potting soil and mix it half and half with coconut coir. Be sure to get a premium coco coir that states it has been rinsed. We use this one from Plantonix.

Be sure that if you buy a different brand, the coir is rinsed. If it’s unwashed or unrinsed, it has a high salt content that results in stunted growth and poor results.

It’s by far the best we’ve found. Mixing in coir keeps the soil from compacting and hardening, giving room for excellent root growth. Our preferred soil for lettuce is a blend of peat moss, coconut coir, compost, and perlite.

As an added bonus we also use mycorrhizae in a fine powder form. This little gem really boosts the early growth period and sets it up for sure success. Sometimes you can find a good organic potting soil that includes this but the choice is yours to add this or not.

Seeding

Fill your pot to the top with the soil mix. Make a small hole in the middle, just enough for the seed to be lightly covered with soil when you’re done. Use a sprinkle of the mycorrhizae that we recommended above. Because lettuce seeds are so small, they don’t need to be planted very deep down, just slightly under a bit of soil.

After that, you should lightly pat the soil and then use a sprayer to moisten well

Transfer to your grow light and leave the light on. This will help the seedling emerge from the soil faster. Then sprinkle with a spray bottle once or twice each day over the seeded area to make sure the lettuce seed is moist but not drenched.

Here’s what to do as the seed begins to germinate and peek out:

Keep the soil moist during germination but be careful not to drench it with too much water, a little goes a long way. Lettuce likes it dryer than wetter. Once the seeds pop up you will continue to keep it moist around the seedlings. Once it is about 1 to 2 inches high, be sure to use enough water to let it soak down a bit.

As mentioned, lettuce needs light to germinate and grow, so the best option for indoor lettuce is a quality LED grow light such as this one. For small scale growing, you will probably only need 1 or maybe 2 light strips for your family’s needs. Generally, the LED light needs to be from 10-12 inches up from the pots until they are about an inch tall and then raise the light up to about 13 inches from the pot.

If you are using 1 gallon pots, lettuce will need to be harvested earlier than the listed maturity date on the package 1-2 weeks sooner. A good way to keep track of this is to write or record your planting date and when it gets to 5 weeks see where it is. Then decide if you want to let it grow a week more. We have found that approximately 6 weeks is average to reach the size we want it. The 2 gallon pots can go to full maturity if you choose full size lettuce.

Thankfully, lettuce is one of the easiest vegetables to grow. You can successfully grow it indoors with a grow light in your pots no matter the season. It doesn’t take a ton of extra maintenance and yields a nice head for harvesting.

Final Thoughts

There are many types of lettuce to choose from, but not all preform as well as others in a pot.

Some of our favorite varieties to grow that are especially good for pots are Salanova types found at JOHHNY’S SEEDS are great performers. These have butter and oak leaf types, mini romaines(both red and green), and several others.

We also recommend these easy to grow types:

Catalina (red tango type, very vigorous)
Cegolaine ( a mini romaine green and bronze)
Deer Tongue ( green tongue shaped leaves that curl )
Dragoon. ( a green mini romaine)
Ezflor (good early vigor and upright habit, red & ruffled)
Ezpark (same as Ezflor but green)
Outredgeous ( attractive smaller ruffled red & green romaine)
Pomegranate Crunch (Adaptable mid-size red romaine)

There are a lot of lettuces to choose from, but not all perform as well in the confined space of a pot.

The packets have about 200 to 500 seeds and if kept in their packages in a refrigerator in small glass jars, they can last several years. some of ours have lasted 4+ years!

So if you want a source of fresh leafy greens that you can grow in any season, give growing lettuce indoors a try. Find what you like and see what works best for you. The flavor is exceptional and it’s so fresh when you cut it yourself.