Grow Closet Herbs

Below is a very brief summary on how to grow closet herbs. At a high level, it covers the basic process for growing soil-based herbs indoors.

Herb soil – It’s best to use nutrient-rich potting soil (Fox Farm, Miracle-Gro) in 8 clay pots. If you have to use regular dirt, microwave it first on the high setting for about 20 minutes to kill off any bugs, insect larvae, molds, spores, and other unwanted things.

Use the best quality herb seeds – Quality plants begin with quality seeds. Seeds for many high quality herbs can easily be mail-ordered. “Feminized” seeds are the best, as they virtually guarantee your plants to be feminine in gender and not the worthless male plants that should be thrown away.

Germinating herb seedlings – Poke a hole about 3/4 deep into your potting soil, drop one seed into it, cover lightly with soil, and water. It’s important to keep the soil moist – but not necessarily soaked – at all times during the germination stage, which can last as long as ten days. (Some growers insist on germinating seeds on wet paper towels and transplanting them once they’ve sprouted, but it’s unnecessary work and you run the risk of killing your delicate sprouts if the paper towels dry out.)

Use fluorescent and HPS lighting – During the early vegetative growth stage, fluorescent lights work well for getting rapid growth out of your herbs. Later on, when your herbs are ready for the flowering stage, switch them to high pressure sodium (HPS) lighting which has a shorter, redder wavelength. You can use fluorescent throughout your growing cycle, but it will reduce your ultimate herb yield when it’s time to harvest.

Nutrients for herbs – All plant fertilizers contain nitrogen (N), phosphorous (P), and potassium (K). When you read the label, you’ll see the ratios of each of those nutrients listed in an order similar to 2-4-8, 2-1-1, or something similar. While in the early vegetation stage, herbs need more nitrogen and phosphorous than potassium. In the subsequent flowering stage, the plants need more potassium to help their flowering process. You can use either powder-based or liquid fertilizers with equal confidence.

Water your herbs – Using tap water is perfectly fine as long as you allow the chlorine in it to evaporate overnight, and it must be at room temperature when watering your plants. Once you’ve mixed your nutrients with the water, make sure that the ph balance of the mixture falls somewhere in the slightly acidic range (between 6 – 7 ph). If your mixture is too alkaline, add phosphoric acid to it, or something similar like white vinegar.

Grow closet temperature – Herbs are hardy and can usually tolerate a wide range of temperatures. Herbs will flourish if you keep them anywhere between 10C (50F) and 32C (90F). Higher temperatures require more water.

Using CO2 with your herbs – It’s been shown fairly conclusively that pumping CO2 into your grow space speeds up the vegetative growing process by as much as 20%.

Pruning your herbs – Since herbs’ broad leaves are the photosynthetic engine for plant growth, you don’t want to lose too many of them. Many growers only trim leaves to allow greater light levels to reach lower into the plants.

Flowering your herbs – When growing outdoors, the plants will automatically begin to flower when they sense fall approaching (the days get shorter and dusk comes earlier each evening). If growing indoors, simply switching from an always-on light schedule to a 12 hours on / 12 hours off schedule will trick the plants into thinking fall is approaching, and herbs will begin to form.

Harvesting / trimming your herbs – Once your herbs have flowered fully, cut them down, and trim off any leafy material that doesn’t look like fresh herb. Use a sharp pair of garden shears to do the job quickly.

Drying and curing – It’s important to fully dry your herbs before using, so once harvested, hang them upside down for a couple of weeks. Put them in a dark space with good ventilation. To check them for readiness, bend a stem; if it snaps off cleanly, your herbs are ready.

Pieter Grundolf writes regularly about his interests in indoor gardening, horticulture, and other related topics. In this article, Pieter shares his knowledge of how to grow closet herbs and, in general, how to grow in a closet efficiently and for practically no cost.