How to Grow Lettuce and Kale Indoors to Beat the Winter Gardening Blues
If you're in cold weather regions such as our home in Southern Colorado, gardening is a part time hobby at best. First frost to last frost can be 8 months or longer. However, just because your garden plot in the back yard looks more like “Ice Road Truckers” than “Square Foot Gardening” doesn't mean you can't have certain home-grown veggies for the table. And no, you don't have to build an expensive custom greenhouse. All it takes is a little planning, a few extra supplies and an unused space in the basement or utility closet.
My home's layout includes a utility closet in the basement, which also incorporates the space under the basement stairs as otherwise wasted space. I decided to use that space to grow relatively low-growing veggies such as kale and lettuce while waiting for the spring thaw.
Uniformly sized pots
Potting soil (we used leftover “Mel's Mix” from our Square Foot Garden experiment of last summer)
Lights (discussed more below)
Watering method (we are carrying over our gravity-fed drip line idea from last year)
Let There Be Light
The primary problem with growing food plants indoors is providing an appropriate amount of – and type of – light. If the light source is too high above the seedlings, they will get 'leggy' and the weak, long stem will collapse under the weight of the initial leaves. A light source too close and too hot will result in poor germination rates for most types of vegetables.
Another concern is making sure that the wavelengths of light produced by the source is appropriate for what you're trying to grow. Certain types of bulbs will create beautifully bushy, green plants but will never induce the plant to flower. Big problem for tomatoes, strawberries, peppers, etc.
Last year for our initial attempt at indoor growing, we purchased a relatively inexpensive fluorescent tube light from Home Depot. After some research on the right color / 'kelvin' rating for the bulb itself, (a topic for an upcoming hub) we purchased and set up our planting area. Due to budget constraints, we did not opt for the fancier and higher-powered grow lights that are available. Besides, some of those just screamed out 'DEA watch list.'
Finally, if you're going to grow your inside veggies in a basement or unused space, it's important to have a timer to regulate how much light they get. The goal is to replicate as much as possible the normal sunlight patterns they would get outside. Plants need darkness for their photosynthesis process as much as you and I need sleep. So a reliable way to ensure the grow light gets turned off and on regularly is vital.
What We Learned From Our First Time
We learned some of the key lessons last winter and are trying to adapt this year.
Use all uniformly sized pots: Since it's so vital to the plant's initial health that the grow light be a consistent and correct height, you can't have the seedlings starting out at different heights in different pots.
One variety of plant per light source: Related to the pot size issue, mixing tall and short plants will keep you from being able to keep your light source at the right height for different plants. We had onions and lettuce under the same light last year, and managed to kill both.
Use a gravity-fed drip line: There are few things more annoying than having to maneuver around a light source to water your plants. Especially with the risk of getting electrocuted if you mess up. We used leftover dripline and emitters from our landscaping project and a spare bucket to water the pots evenly and safely.
Pre-soak your potting soil: Since the only water your soil will ever get is that which you provide it, it's safe to say that watering the top of dry potting mix results in uneven moisture throughout the mass of soil. Water will find the path of least resistance from the surface to the little drain holes in the bottom. Drought-level dry areas in the center of the pot will be the result. Therefore, we thoroughly mix our potting soil with water by hand before scooping it into the pots. Wicking action once you water evenly moist soil will keep all of the cylinder of soil full of root happiness-inducing moisture later.
Better Than Store-Bought, but Still Not Quite the Real Thing
Keep in mind that while leafy vegetables grown indoors under artificial light will still be as pesticide-free and healthful as you choose to make them, it is not quite the same thing as growing food outdoors. Some of the health benefits of kale and lettuce, like antioxidants in vegetables are formed as the plant itself 'battles' changes in temperature, wind, etc. Too calm an environment keeps those from being formed. So once the spring thaw comes along, you still want to use your outdoor garden. But during the winter months, this method sure beats the carbon-intensive and non-organic process of shipping veggies thousands of miles to your local supermarket. If you are inspired to grow indoors during the depth of winter and organically outdoors in-between the frosts, you can learn how to grow organic kale in this article.