If you love your greens, then growing lettuce indoors should be a priority.
Lettuce contains several vitamins, minerals, and antioxidants which are vital for human health.
Growing lettuce indoors is also an intriguing pastime since there are so many different varieties. Each one has its own taste, aroma, appearance, and benefits.
Growing these greens indoors is also a straightforward process. When you have the correct container, soil type, and seeds, all you need is a regular supply of sunshine.
If sufficient sunshine is not an option, you can always add grow lights to your shopping list as a solution for growing lettuce indoors.
Why growing lettuce is good for you
Some people like hot vegetables while others like to eat their greens cold, in salads or sandwiches.
Lettuce is versatile, and people usually enjoy it cold, in salads, and as tasty, crispy additions to sandwiches, in soups, and when making a tuna, chicken, or pepperoni salad. Lettuce also makes a terrific addition to cold pasta meals and soups.
You also get a magnificent variety, catering to all growing conditions throughout the year for growing lettuce indoors. With such a large variety of this healthy green, growing lettuce indoors is a worthy pastime, especially when your greens are organic.
Here are several lettuce varieties that you can grow indoors throughout the year:
Kale (not entirely lettuce but similar enough to include in this list)
Arugula (rocket or Italian cress)
Frisée (belonging to the radicchio, endive, and chicory family)
Endives (part of the radicchio family)
A variety like the Romaine lettuce contains multiple nutrients, including:
Vitamins A, C, Folate, and K
Lettuce contains beta carotene, which the body transforms into vitamin A
Minerals like potassium, phosphorous, calcium, and magnesium
Lettuce contains low volumes of sodium, is low in fiber, carbohydrates, and calories
Elevated levels of antioxidants
Eating lettuce has several benefits due to its nutritional content. Certain of these benefits are appropriate for increasing bone and teeth strength.
These nutrients also support the immune system, cell, nerve, and muscle health and prevent blood clotting. In addition, eating lettuce is excellent for the reproductive system, eyes, lungs, kidneys, and heart.
Overall, there is every reason for you to start growing lettuce indoors for a year-long supply of healthy nutrition.
When to plant it
Nothing prevents you from growing lettuce indoors throughout the year.
This planting method is ideal if you enjoy your greens, enabling a constant supply of these healthy greens whenever you want to add them to your diet.
If your indoor space gets enough sunlight, you can have a supply of these fresh greens for twelve months. If not, you can always buy LED grow lights to support the growth of these plants in the winter.
However, if you aren’t growing lettuce indoors, the right time for planting is during the spring and fall months. So long as the soil is warm and you can work it, you can plant lettuce.
Ideally, soil temperatures should be at 40°F, but it should be as warm as 65°F for seed germination. Lettuce seeds will start sprouting within ten days.
If you buy small lettuce from a plant nursery, you can transplant them a little before expecting the last frost to occur.
If you start germinating your growing lettuce indoors, then you can transplant them into larger containers approximately fourteen to twenty-one days before the last frost. As long as the plants are sturdy, they’re ready for transplanting.
After planting your first round of lettuce indoors, you can sow seeds twice a month for a constant supply of these greens throughout the year.
Container or raised bed
Select shallow containers for growing lettuce indoors. Flat, rectangular, or square containers are perfect for this purpose.
You can even recycle containers for planting if they allow for good soil drainage. Otherwise, simply create holes in the bottom of the containers to create a sound drainage system.
Recycling containers such as take-out foods or those with transparent covers are ideal for growing lettuce indoors. These covered dishes create a greenhouse effect, which promotes rapid growth, especially in the winter months.
Containers for growing lettuce indoors should be at least four by six inches. If you prefer, you can use containers with multiple cells to start seed growing and then transplant the lettuce to larger planters once they are big enough.
Lettuce varieties typically have shallow root systems, so the depth of the container is not that important. If you have the space for raised beds, these will also be appropriate to grow lettuce indoors.
Ensure the container is large enough for at least six inches of dirt and can accommodate at least a gallon of earth. It will be enough to grow the lettuce. If the container or raised bed is large enough, it doesn’t matter which one you use.
Soil to use
When growing lettuce indoors, several varieties are more suitable. Lettuce varieties with loose leaves are the best for a year-round supply. These types include Tom Thumb, Seeded Simpson, and Baby Oakleaf.
Arugula also does well indoors. You can plant the seeds of Winter Density, Arctic King, or Winter Marvel during the winter as they do well in the cool winter sunlight. Please do not attempt to grow head lettuce varieties indoors as they are typically not successful.
Other varieties that are excellent for growing lettuce indoors include:
Red Deer Tongue
Use a soil type that is suitable for seed germination. One product that does well for growing lettuce indoors is the Seed Starting Mix, for example.
Gardeners should also avoid using potting or garden soils as these are far too coarse for seed germination.
If you choose to use ordinary garden soil, then enrich it with old, well-rotted compost, a fish emulsion, or manure. You can use other additives, but you should allow the soil to settle for several months before planting, no matter what you use.
Amending the soil in this way gives the other mediums time to decompose properly, become embedded in the ground, and prevent nitrogen burn to your plants. Allow the earth to stand for at least three months before planting.
How often to water
Growing lettuce indoors is relatively maintenance-free.
However, these plants do well with a regular weekly soil soaking with water. If you provide these greens with regular but moderate volumes of water, they should thrive.
If you’re growing lettuce outdoors, the summer temperatures will mean that your plants need more water. Also, if your area is suffering from a lack of rainfall, more regular watering will be necessary.
Mulch the lettuce around the root area to keep the moisture in the soil. You can use a treated straw to prevent contamination for mulching purposes or a layer of compost.
Either of these mediums will ensure water retention without providing the plants with too much water, which can cause the roots to rot.
Because you can continue picking lettuce leaves from the live plant, you should provide these plants with plenty of fertilizer. Growing lettuce indoors means that they must have a constant food source to support leaf growth.
Growing lettuce indoors requires a rich, fertile soil for seed germination. The best fertilizer is a granular or water-soluble one with equal nitrogen, phosphorous, and potassium.
If you see fertilizers with the numbers 5:5:5, or 10:10:10, then they will be ideal for supporting lettuce growth if they’re in a liquid or granular form.
Fertilizing growing lettuce indoors or outdoors is particularly necessary due to ongoing harvesting. However, it is also essential to maintain the soil nutrients when growing these plants continuously throughout the year.
Mix the granular or water-soluble fertilizer with water in a ratio of 1:1 and feed this mixture to your plants fortnightly.
When growing lettuce indoors, a few pro tips are always helpful.
Pro-tip #1: Place your containers in a south-facing window to ensure your lettuce receives enough sunlight.
Pro-tip #2: If your home does not receive enough sunlight, consider purchasing plant grow lights to enjoy lettuce harvests for the entire year.
Pro-tip #3: Plant lettuce close together to prevent weed growth as lettuce does not like competition.
Pro-tip #4: Remove all large clumps from the soil as lettuce seeds are so tiny that they will struggle to bypass large elements in the dirt.
Pro-tip #5: Only plant seeds at a depth of one-eighth or a quarter of an inch, as these plants need loads of sunlight to germinate.
One of the most notable advantages of growing lettuce indoors is that you can harvest this vegetable all through the year. If you have some gardening friends who live in small spaces, coordinate your planting with them.
You can grow lettuce indoors, and they can grow other crops to complement each other. Using this strategy will provide several homes with fresh, organic produce and avoid the necessity of regular shopping for fresh food.
Tyler C Rich is the founder and chief editor at TopsyGardening.com. An experienced gardener and a professionally trained agriculture development expert, Rich has worked in the gardening and landscaping industry for more than a few decades. Although he has retired, his spark for developing the best urban and indoor gardens has not faded a bit. He uses TopsyGardening.com as a platform to come across enthusiastic gardeners and share the unique insights he has acquired through years of experience. Rich is interested in aquaponics and technology apart from conventional gardening techniques.