Growing edible plants indoors is really not much different that growing houseplants. The concept is not a new one, dating back into Victorian times with atriums and greenhouses becoming popular in many homes. Housewives have been growing herbs on sunny window sills for centuries. Home gardeners have been starting plants indoors under lights for ages and now those systems have become even more popular. Essentially, the basic requirements of growing medium, nutrients, light, water and temperature need to be met in order to successfully grow edible indoor plants year round. Logistically, one of the biggest problems with growing an indoor garden is space as all the other growing conditions can be controlled.
There are table top soil based, hydroponics and aquaponics commercially produced growing systems are available but many home gardeners set up DIY systems that take advantage of natural light supplemented with artificial lighting. It is even possible to have small ponds indoors made rather easily with preformed pond shells. Think outside the box if using aquaponics or indoor ponds as the fish in the system can be used as food (eg. shrimp, bass) as well rather than decorative (eg. gold fish, rosy red minnows).
Houses are apartments can create growing restrictions based on their orientation and design. This is our sixth owned permanent Canadian residence. While we also own a vacation home in the US, we don't grow an indoor garden there. Of the six homes here, only one was almost ideal for an indoor garden because it was open concept with massive expanses of windows (south and west exposure to a fault) for natural light so supplementing with artificial lighting wasn't really needed. I am in the process of setting up my indoor gardens. While it is partially set up, it is very much a work in progress at the moment. This house has wonderful southern exposure, only one window facing west, a patio door facing east and the rest northern exposure. So while it is light, bright and airy, actual indoor growing space is limited. Ideally, I would like to take the other spare bedroom and turn it into a grow space but hubby already called dibbs on it as an extension of the games room. Here are some of the things I am taking into consideration in establishing my indoor garden:
- lighting - I'm taking advantage of two large windows with deep windowsills adjacent to each other on the lower level. One faces south and the other west so there is a lot of natural light. The windowsills are about a foot deep giving plenty of room for lots of pots. This area of the house is ideal for herbs, starting seeds, growing vegetables (eg. tomatoes, lettuces, peas) and overwintering geraniums. At the same time the light spills into this portion of the games room making it the perfect spot for larger potted plants to get plenty of natural light. I am in the process of setting up a shelf unit that was initially a small patio greenhouse (4 shelves) as a growing station that will be mainly artificially lit. Other than that, I take advantage of natural lighting by moving plants around as necessary.
- heating - Heating is a non-issue for the most part. We keep the ambient temperature at 20°C during the winter months with the exception of the period of time we are at our vacation home when the temperature is lowered to 13°C. The problem with indoor heating is it can be quite drying. In our previous houses this was a problem that I solved by using humidity trays and misting. This house has an air exchanger so the air does not get as dry. I use vent deflectors to keep the heat from blowing directly on the plants.
- watering - Fruits and vegetables grown indoors require more watering simply because there is not a natural source of water (eg. rain) but at the same time there is less water lost through evapouration due to winds, high temperatures and strong sun exposure. Overall, plants grown indoors require less water and they should only be watered as needed. Over watering of herbs, fruits and vegetables grown indoors will cause: mold to form on the soil surface, root rot that will result in the death of the plant, and promote fungal diseases. Not only is this bad for the plants, mold spores can trigger allergic reactions and asthma. Watering is done by hand but I do take advantage of water globes and self-watering pots to lessen the amount of watering I have to do.
- humidity - Plants grown indoors require humidity especially during the heating and cooling seasons, both of which can be quite drying. Humidity helps to keep the stomata on the leaves clean so the plant can respire properly. Outdoors this task is done by humidity and rain. Indoors, it can be achieved by occasionally giving plants a shower and routinely misting them to keep the leaves free of dust that will block the stomata. I also set up humidity trays for some plants, especially those close to any heating vents. A humidity tray consists of a shallow plastic tray with a layer of stones covering the bottom to which water is added then the potted plants sit on top of the stones.
- fertilizer - Any plant grown in containers whether indoors or outdoors requires fertilizer to replenish the limited supply of nutrients in the soil. I work in compost, coffee grinds, and used tea leaves into all of my houseplants including the edible ones. I also use an organic fertilizer.
- pollination - Plants grown outdoors are usually pollinated by bees and other beneficial insects as well as the wind although the home gardener may also manually pollinate certain plants. Indoors, there shouldn't be any pollinating insects and while there are air currents in the home, they likely are not strong enough to ensure pollination. In most cases, manual pollination is required using a small artist brush (dollar store) or q-tips.