Let’s take a look at how to grow greens indoors. For the sake of this post we are going to focus on fast-growing greens like lettuces, arugula, and spinach. While it is possible to grow kale and other dark leafy greens indoors, it will be an exercise in patience at best. In my experience, kale does not grow well indoors at all – it is slower growing and will end up spindly regardless of how much light and nutrition you give to the plants. If you want to grow kale over the winter I suggest planting it outdoors in raised beds in the fall and overwintering it with a cold frame or other protection.
When it comes to growing vegetables inside, lettuce greens are some of the easiest to grow. They require very little maintenance so long as the conditions are favorable for their growth, which is great for freshman gardeners. Here’s how to do it:
2. Sprinkle seed atop the soil and cover by sprinkling with more soil to a depth of about 1/8”.
3. Water lightly but thoroughly and place container in a cool, well lit area.
If you are using an artificial light source, situate the container as close to the light as possible. When growing seedlings indoors for spring transplanting, I keep the light source about 3” away from the plants. Allow for 8-10 hours of light per day, but don’t be surprised when your indoor-sown lettuce seeds don’t grow as quickly as they do outdoors. They will grow, but they will do so much more slowly.
To ensure that your lettuce gets adequate hydrating, keep the soil moist but not wet. I find that using a simple misting bottle daily is often enough to do the job.
As a general rule, you can expect to add as much as 2-3 weeks to the growing time when growing lettuce indoors, but growing it in winter can bring much-needed fresh green to the table in the colder months.