You know all those grow-your-own basil kits sold online and in novelty stores? I do not understand them! For starters, they almost never work (or they do ... until they don't). And secondly, they're just totally unnecessary. Basil is actually not hard to grow, and you'll have a lot more success if you just do it sans kit.
Here's what you need to know about growing basil in your kitchen without a kit. Armed with this info, you won't ever have to buy one of those overpriced packs of basil at the grocery store ever again.
First, the Basics
There are all sorts of basils out there. Commonly, we use sweet basil or Genovese basil in cooking — this is the historically Italian herb that tastes of mint, clove, citrus, and anise all wrapped into one. There's also Thai basil, lemon basil, anise basil, lime basil, cinnamon basil, and more. The colors can range from lime green to deep emerald, and the leaf size will also vary across plants. Genovese basil produces big, puckered leaves that are fleshy, for example. Other varieties will grow as small bushes and produce small, pointed leaves.
If you're thinking, "Hey, didn't you guys already say mint was the easiest herb we can grow indoors?" You are not wrong. Mint is a perennial herb, which basically means you can grow it any time of year and it will keep coming back. Basil, however, is an annual herb and prefers warmer temps (plant it around May or June) and won't last much more than a couple of months.
That mint story: The Easiest Herb You Can Grow Indoors
Basil should be grown in a pot that's at least four inches deep. Of course, the deeper the pot, the more the plant will fill in, so keep that in mind when choosing. Fill the pot with potting soil so it's flush with the top — do not leave any space, as that would create a small shadow, blocking growing plants from sun.
Basil can be sown (planted!) from seed or purchased as a transplant (a plant that's already been started for you!). You can find sweet basil starter plants at the grocery store, but if you want to grow a less common type, you might have to look for seeds.
If using seeds, you can be super casual about it: Just sprinkle the seeds across the top of the soil with no particular pattern (it's called broadcast sowing). This method works for stem-y plants — like basil — that can grow close together without crowding.
If transplanting, the only real rule is to provide enough space for the plant to grow. Loosen up the transplants and be sure to separate out individual basil plants, allowing them room to come to full maturity. Trim any very long root systems to about three inches long and plant them into the potting soil, making sure you don't cover too much of the stem. Basil stems are delicate and will rot if planted too deeply.
More on seeds versus transplants: What's the Best Way to Start a Garden?
As with most container plants, keep the soil just-moist and water consistently. Aim to water your basil plants in the morning — the warmer they are, the happier they are. If you water them at night, their root system will cool down, which is not ideal!
Harvesting basil is always a process of great debate and strategy. Basil is an annual plant, and so its character is to flower and set seed. Once flowering, the plant won't grow many leaves, so it's important to keep them from flowering.
How do you do that? When the plants are young (about six inches tall) pinch off the top set of leaves every two weeks or so. The plants will branch out from here, filling in the pot. Do not wait for flowers to form before you pinch them off! Doing so will only create more flowering stems. (Whoops!) If it does flower, just pinch them off (you can eat them!). As you harvest, limit what you take to just up to 2/3 of the entire plant, so it can continue producing.
To make sure you keep yourself in good harvest stocks, sow a small spoonful of seeds every three weeks starting in June. This ensures as some plants are coming to the end of their lifecycle, more are growing behind it.
More on Basil
About me: I'm a cook and urban farmer, and I wrote a book called Apartment Gardening. I believe that growing your own food is a natural extension of eating healthy and eating well — and that anyone can do it, no matter how little space you have.