Home of the Food Bowl Solution!
Spinach, lettuce, endive, Swiss chard and other leafy greens are cool weather crops and can be sown by seed, into containers that are 10 to 12 inches or more deep (they have deep roots). Seed and growing containers are available at any garden center, or from online catalogs. Leafy greens do better in temperatures around 65 to 70 degrees, although lettuce enjoys even cooler weather. Seeds will not germinate indoors or outdoors if the temperature is 80 degrees (27 C) or warmer. Sew the seed directly into the growing pots and do not attempt to transplant them. Once they germinate and start to grow, they will bolt and go to seed swiftly if it gets too hot. Lettuce is more tolerant because hot weather varieties are available.
If you want to enjoy repeated cuttings over extended periods of time, then maintain ideal growing conditions indoors. When growing indoors you will want to grow your greens where both day and night temperatures, as well as and the amount of light available each day are appropriate, as described above.
Most leaf greens like spinach lettuce, endive, and Swiss chard will tolerate daytime temperatures in the low to mid 60's and even do well with cool nighttime temperatures that dip into the upper 30's.
Light is also an important consideration; leafy greens require at least 6 to 8 hours of sunlight. Tender leafy green plants are susceptible to cold that radiates from the windows; therefore, keep them back somewhat from windows if temperatures outside are too cold.
If you don't have a bright area in your home or porch that enjoys sunlight, then you can supplement lighting with a combination of cool-white and warm-white fluorescent lighting. Growing lights can be purchased very affordably at any local garden center or online. They are inexpensive to buy and use, and they are easy to set up.
For indoor vegetable gardening, do not use rich soil with lots of compost, as you would if you were planting outside; rather, use lightweight soil mixes that drain and breathe better. For example, use 1 part potting soil, 1 part vermiculite, 1 part peat, and 1 part perlite. Again, your gardening center can help you.
Water the spinach and lettuce and keep the soil evenly moist, but not wet; allow soil to dry out some between watering because the soil needs to aerate in order to prevent the seeds from rotting. When growing inside it is important to fertilize every two weeks with an organic fertilizer such as a 15-15-15 or a 20-20-20 that can be obtained at a gardening center.
When growing indoors, pests that are common to houseplants are also attracted to vegetable plants. These pests include the whitefly, spider mites, and mealy bugs and perhaps others, depending upon where you live. From your garden center obtain a treatment for your plants similar to what you would use with houseplants and they can help you use treatments best suited to your area. However make sure that what you use is safe for edible plants.
Disease is more common when growing indoors because of the lack of diversity in temperature, which kill off various pathogenic organisms during the different seasons of the year--when it gets really hot or really cold. When growing indoors, pick varieties that are more resistant to disease and go with a recommendation from your local garden center. Lettuce is more hardy than spinach and any variety should generally yield good results.
Plant according to directions for both depth and spacing; germination varies between about 7 to 14 days. Once germinated, thin spinach to one seedling every 3 inches and lettuce to one seedling every 6 inches. Spinach and lettuce are ready to harvest when the leaves are big enough to pick. You can either pick or cut the leaves away from the base of the plant. Then cool the leaves immediately by washing them in cool water before eating them or storing them in a refrigerator. They store well up to about 14 days, although when growing your greens indoors there is no need to cut more than you will eat daily.
As long as you fertilize every two weeks, you can enjoy multiple cuttings from the same plants; they will continue to grow back indefinitely, or until exposed to hotter temperatures that will cause them to bolt and go to seed. Give indoor or outdoor growing of leafy greens a try and learn just how easy it is.
I wish I would have been able to read this article last October....I would have tried growing greens inside. People (including me) have been asking just this very thing - wondering what it would take to do it. Thanks for posting it. My mind is churning.....