This is the first chapter in my forthcoming book Indoor Gardening: Growing Herbs, Greens, & Vegetables Under Lights — book #4 in The Hungry Garden series. I’m still all tangled up in the chapter about Lighting (there are a lot of concepts I haven’t dealt with before, so I’m trying to break everything down so you-all can understand it … which means I have to first break it all down so *I* can understand it) but I hope to have the book finished soon and out into the world at last!
“Honey, Where Are You Putting All These Plants?”
The problem with time and space as we know it means that we can’t have a house like Dr. Who’s Tardis. Outside, it looks exactly like a police box; inside, you have 500 square miles of space, plus a pool (I have no idea if Dr. Who had a pool) and a room for really long scarves (for Tom Baker).
So if you’re like me and you have a house that has, and this is a rough but accurate estimate, about 25 square feet of space — then finding a place for more plants is a challenge.
Not that this has stopped me from buying more indoor plants, oh gosh no.
But if you want to grow food plants indoors, then finding a good location for them is going to take a little more effort. At minimum you’ll need 1) a space large enough for your plants to grow to their full size 2) in a place that completely fills their light needs.
If you are design savvy, you’ll also need 3) all plants and materials to be aesthetically pleasing. This book probably will not give you very much on this score, for which I’m very sorry. My decoration ideas are like, “This space can be improved by piling a bunch of books on top of it, along with this cool rock I found.” So, I’m not exactly your go-to source for interior design inspirations.
But I’m here for all your plant information needs, so let’s gooooooo!
Plants grown for food instead of aesthetics will need full light, whether from the sun or from supplemental light. A flat of lettuce can survive on the kind of light you give to a dracaena or a pothos or some other low-light houseplant — but the lettuce plant won’t be happy, and it won’t bear the tasty greens that you planted it for. It will be tall and leggy and sad and pale, like ghost lettuce. You don’t want to make a salad that looks like Bunnicula has been raiding the vegetables in your fridge.
So, let’s start with the first step of garden prep, whether that garden is inside or outside: Assessing what you have and figuring out how you can make it work.
Assess Your Site/Window
This is no different than setting up an outside garden, beside the fact that there will be no digging. And you’re inside.
So take a look at the space you’ve decided to give to your plants. If it’s near a window, how much light will the window provide? Do you need to supplement that light with an artificial light source? And, if so, is there a plug-in nearby? If not, do you have an extension cord long enough to reach it? And can you place that cord where nobody is going to trip over it?
I really didn’t expect to have to do THAT much thinking over where to put a pot of herbs, but here we are.
But this is a big deal: Some of these plants are going to take a lot of light. I mean a LOT of light.
Higher levels of light will generally lead to higher yields for most plants, specifically, larger crops like tomatoes. However, if you’re growing some lettuce and sprouts, you’re not going to need to capture the entire sun and put it in your living room.
You might have to find a way to block the light from the rest of the house, like putting up a partition of some sort. You can put up a reflective layer facing the plants to bounce some of that extra light back on the plants, like a space blanket. Grow tents are another option for folks with a couple of bucks.
When it comes to costs such as grow lights, soil, shelves, and the electric bill — again, start small, especially if your financial resources are stretched thin. It’s just a good idea to start small, anyway. As any plant aficionado knows, it’s easy to add to the collection but harder than heck to trim down the population once you have plants heaped upon on every lighted surface in the house. So it goes.
Start with a couple herbs and some lettuce under a cheap grow light. Put a little pot of carrots in the window.
Use an old tray from a greenhouse to grow microgreens. Instead of buying pots, poke holes at the bottom of a cottage-cheese container and use that. Old milk jugs and 2-liter pop containers, cleaned out, can serve as pots or mini-greenhouses, depending on which side you put the soil in. Rotisserie chicken containers or large containers for lettuce make instant small greenhouses.
Gardeners have always been the ultimate reusers. They save bits of twine to tie up plants, reusing old pots, saving seeds from year to year to plant them again. Compost is simply the art of repurposing old scraps — you don’t even have to buy a compost-turner or a fancy bin.
There’s no shame in looking for cheap alternatives. Really, it’s an ecologically-friendly way to live. Spend your money for things you actually need, and MacGyver the rest!
What Plants Need
Now that you’ve found your location, let’s take a moment for a quick overview of the general points of what your container-grown indoor crop plants will need to thrive.
Light!! — This is the big issue in indoor gardening, so I hope you’ll forgive me if I save this part of the discussion for later in the book — I will be devoting several chapters to lighting, grow lamps, and a bunch of other interrelated details.
Air — Hopefully your home has plenty of this. If it doesn’t, I highly recommend moving, because being able to breathe really improves the quality of your life!
Seriously, have some air circulation around your plants. Have a fan running to keep air moving through the plants to discourage fungal diseases.
Soil — For indoor plants, soil is replaced by soilless mixes. The actual potting mix you get from the store is made of mixes of light materials such as peat moss, coir, perlite, and other sterile ingredients. Get a bag of light potting mix from the store. Don’t use top soil or dirt from outside, as this can bring diseases inside and will become too compacted in the pot.
Containers — Choose pots that are large enough for your plants to prosper. If you’re raising seedlings, use trays that you’d get from the local garden center. And make sure all pots have drainage holes!
I go into a lot of detail about soil and containers in my other book Big Yields, Little Pots: Container Gardening for the Creative Gardener, so if you have any questions about soilless potting mix and the wide array of pot materials that you could use, skip over and grab a copy of that book because it will load you up with all the specs.
Water — One aspect of container gardening that’s often overlooked is the water. To understand why, we need to talk a little bit about plant physiology and chemistry.
So plant roots basically are able to draw nutrients to them due to postitvely-charged ions. Specific nutrients (which are different chemicals) are attracted to these ions. The pH of the soil and water can affect how well these nutrients are absorbed — or can hinder them. Nutrients have pH ranges, within which they’re able to be absorbed. But if the soil or water are at the wrong pH, the magnetism between the nutrient and the plant root is reduced, so the root cannot absorb the nutrient.
We see this in oak trees that are planted in alkaline soils. The develop a condition called chlorosis in which their leaves turn yellow-green. Chlorosis is caused by the roots not being able to absorb the iron in the alkaline soil. If the oak tree is planted in acidic soil, it’s easily able to absorb the iron and the leaves are a nice green color.
So if your plants seem to be struggling, you might get a pH pen and use it to check two things: The water you are using to water the plants, and the soil in the pots. Then look at the pH requirements of your plants to see if you need to use filtered water, or change your potting soil.
Don’t overdo watering. It’s okay to let the soil dry slightly between waterings. Seedlings and seeds should stay moist but not continually soggy.
If you have rain barrels to collect rainwater, use this to water the plants. Cities treat drinking water to make it safe to drink, adding chemicals such as chlorine or chloramines to kill bacteria, and occasionally fluoride to prevent tooth decay. If you soften your water, that contains added salts. Rainwater contains few salts or chemicals, but actually contains a little nitrogen that was converted by lightning in the atmosphere, which is also good for plants.
Some plants don’t react well to the minerals in tap water — and saving rainwater is both cost-effective and just a healthy thing to do.
Fertilizer — Add a granular, slow-release fertilizer to the soil before you plant your seeds. Or you can fertilize the growing seedlings and grown plants with a water-soluble fertilizer every two weeks. Don’t fertilize more often, as fertilizer tends to build up over time in the soil in the form of salts, and can eventually make the soil inhospitable to the plants. Fertilizer might also affects the taste and smell of some plants.
Temperature — Best about 70 degrees. Don’t place plants next to a heating or cooling source.
Humidity — Plants need humidity! During winter, houses can have as little as 20% humidity — about the same humidity level as the Sahara Desert. Use a humidifier.
Check out Indoor Gardening: Growing Herbs, Greens, and Vegetables Under Lights — it goes live on December 1, 2022, at your favorite online retailers!