Grow Lettuce Indoors
Lettuce is a surprisingly easy crop to grow indoors. It has a short-term but plentiful yield and only requires minimal care: standard potting soil, a little water, and a lot of sun is all it really takes. This vegetable is so easy to grow, in fact, that you can skip traditional potting altogether and sow your seeds into disposable plastic bags.
Contents
Steps
Method 1: Traditional planting
Part 1: Preparation
- Choose a lettuce variety well-suited for container gardening. Loose-leaf varieties are the easiest to grow indoors, especially if the name includes "baby" or "little."
- Select a medium-sized plastic pot. Lettuce does not have a particularly deep root system, so a medium container should offer plenty of room. Plastic works better than terracotta clay pots, since clay absorbs water and dries out the soil faster than plastic.
- If using a clay pot, line the pot with a plastic shopping bag before you plant your lettuce seeds. Make holes in the plastic bag to allow water to drain.
- Make sure that the container has drainage holes. These holes will allow excess water to escape if you water the plant from the surface. Holes also allow you to use a watering tray technique which is especially beneficial for lettuce plants.
- Clean your container, especially if it once held another plant or object. Bacteria and insect eggs could be lurking inside the pot, waiting to destroy your plants. Standard soap and warm water should kill most potential threats, but you can also wash your container out with a solution made of nine parts water and one part bleach for a more thorough cleansing.
- Select a standard potting soil for your lettuce. Loose-leaf lettuce is about as "no fuss" as a vegetable can be, so you don't need anything fancy. A standard all-purpose potting mix should work just fine. Avoid using dirt from your garden, however, since this may contain bacteria and insects that could damage your crop.
- Fill the pot with soil. Fill it high, but not to the very top. You should leave about an inch (2.5 centimeters) or so of empty space in between the surface of your soil and the rim of the container.
- Pour one or two dozen lettuce seeds into your non-dominant hand. Lettuce seeds are small, so the pile of seeds in your hand should look relatively small, as well.
- Pinch the seeds in between your index finger and thumb on your dominant hand. You do not need to get all the seeds with your first pinch. A small amount is enough to start with.
- Sprinkle the seeds in your dominant hand over the top of the soil. Try to avoid dropping too many in the exact same spot, but you do not need to worry too much about how far apart the seeds are spaced at this point in time.
- Repeat the pinching and sprinkling procedure until you use up your original pile of seeds. Pinch the seeds in between your index finger and thumb and sprinkle them over the soil.
- Sprinkle additional potting soil over the seeds. Only cover the seeds with 1/8-inch to 1/4-inch (1/3-centimeter to 2/3-centimeter) of soil. If you use any more soil than that, the seeds will not be able to receive the light they need to germinate.
- Use a spray bottle to spritz the seeds with water. The soil should be thoroughly moist, but not soaked.
Part 2: Care and harvesting
- Mist the lettuce seeds each morning. The soil needs to remain continually moist in order to germinate. Germination should occur within one or two weeks.
- Water the plant every other day to keep the soil moist. The lettuce may need more or less frequent watering, depending on how warm and sunny your home is. Check the soil frequently by sticking your fingertip into the top 1/2-inch (1 1/4 centimeters). If it feels dry, the lettuce may be due for another watering.
- Consider tray-watering the lettuce. Place a tray or saucer of water beneath the container and allow the water to travel into the soil via the drainage holes. By watering from the bottom up, you may have more success in preventing root rot and fungal disease.
- Keep the lettuce cool. A room temperature set at 60 to 70 degrees Fahrenheit (16 to 21 degrees Celsius) is ideal. Drop the temperature by 10 degrees Fahrenheit (6 degrees Celsius) at night to mimic natural conditions.
- Place the seedlings in the sunniest window you have. Lettuce seedlings need 14 to 16 hours of bright light in order to grow full, bushy leaves.
- Invest in a fluorescent grow light. If you cannot provide the lettuce seedlings with enough natural light, place the container 4 inches (10 centimeters) beneath a grow light and keep the seedlings there for 14 hours. Turn the light off once this amount of time passes, however, since lettuce plants will not do well under 24-hour light.
- Thin seedlings after they get their second set of leaves. Pull out the weakest seedlings, keeping a 3-inch (7.62 centimeters) space in between the remaining plants to give them adequate room to mature.
- Instead of throwing away the "reject" seedlings, transplant them into separate containers or harvest them for consumption. Lettuce seedlings are edible and taste very similar to mature lettuce leaves.
- Use a mild fertilizer, if desired. Lettuce is a hearty enough plant to thrive on its own, but a mild fertilizer, mixed with equal parts water to cut it down to half-strength, can increase your yield even more. Apply the fertilizer solution to the seedlings once a week for three weeks, and then discontinue use.
- Harvest loose-leaf lettuce as you need it or all at once. Immature leaves are just as safe and delicious as mature leaves.
- Immature lettuce tastes just as good as mature lettuce. As soon as the leaf size is to your liking, you can begin to harvest the outer leaves. Leave the inner leaves alone so that they can develop further.
- You may need to wait about 4 to 6 weeks for the lettuce to mature if you prefer to harvest a fully mature head of lettuce. Collect the leaves individually, pulling the outer leaves out first and gradually working inward. Mature lettuce "bolts" or produces seed quickly, however, and must be harvested before this occurs. Bolted lettuce has a bitter taste.
Method 2: The short-cut way
- Cut off the corners of a large gallon-size plastic bag. The holes should be small enough to prevent potting soil from falling out, but large enough to let water escape.
- Fill the plastic bag with potting soil. The bag should only be about 3/4 full, and the potting soil should be pre-moistened to help keep it inside the bag with its snipped-off corners.
- Place the plastic bag in a tray or on a plate. Excess soil and water can escape through the corner holes, which could create a mess if you allow it to sit out on the counter or windowsill by itself. Placing it in a tray will help you to capture and contain the mess.
- Pour one or two dozen seeds into your non-dominant hand. Pinch a few of the seeds in between the index finger and thumb of your dominant hand, and sprinkle them over the surface of the soil.
- Sprinkle additional potting soil over the seeds. Use no more than 1/8-inch (1/3-centimeter) of soil so that the seeds can absorb sufficient light.
- Spray the soil with water. You only need a light spritz; anything more than that will cause the seeds to drown and cause muddy water to come gushing out of the cut-out corners of the bag.
- Seal the bag mostly closed. Leaving the bag completely open will allow too much heat and moisture to escape, but sealing it completely shut will cause the air inside to grow stale. Leave at least 1-inch (2.5 centimeters) open, "zipping" or sealing the rest of the bag's opening.
- Allow the bag to sit out on a sunny countertop or windowsill. Alternatively, you may also use a fluorescent grow light to provide supplementary light. Even using this method, the lettuce seeds need around 12 to 14 hours of light each day.
- Open the bag after the seeds germinate. Germination should occur within a few days to a week. Continue spraying the soil to keep it moist, and provide the seedlings with the same amount of light as before.
- Harvest the leaves individually as they start to get large. This should only take a few weeks. Pick off the outer leaves first before gradually moving inward. Do not wait for the lettuce to mature into a full head when growing it in a plastic bag, since this short-cut method is not intended to nurture fully mature lettuce.
Method 3: Repurposing Romaine lettuce
- Once you've removed the leaves that you plan to use, pop the remaining stump into a ramekin with a bit of water. No more than 1/2" of water works.
- Place the replanted lettuce where it will get the light it needs, either artificially or on a sunny windowsill. You should notice growth within just a few days.
- Replace the water with fresh water every other day.
- Harvest when needed. While you won't regrow a bunch of lettuce, it's enough to toss fresh greens onto a sandwich.
Tips
- If you have young children or students, plant lettuce with them as an introductory lesson to gardening. Lettuce is so easy to grow that even kids can do it, as long as they have a little adult guidance. When growing lettuce with your child for the first time, begin with the short-cut method, since it is easier and produces results a bit faster.
Warnings
- When adding fertilizer to your lettuce, do not allow the fertilizer to get onto the leaves. Instead, apply it directly to the soil.
- Thoroughly wash any home-grown produce before consumption.
Things You'll Need
- Lettuce seeds
- Plastic container or pot
- Potting soil
- Plastic bag with a zipper top
- Scissors
- Spray bottle
- Mild fertilizer
- Grow light
- Shears or garden scissors
