3 main conditions for growing herbs indoors
Three conditions that are very important for indoor herbs are air circulation lighting and humidity. Most herbs like a fair amount of humidity and a lot of homes lack that, especially during winter. Without air circulation, fungus and mildew can set in, plus the movement of the air helps to stimulate the plant to drink in water and nutrients from the soil as well as help strengthen the stems.
If you’ve ever had plants that had a white fuzzy mold or a mildewy growth on the top of the soil, then the likely reason is that you didn’t have enough air circulation around the plant.
Provide good air circulation for herbs
Providing air circulation to your plants is easy and can be done in several ways. First of all, if you live in a warm climate, you can always rely on an open window or set your plants outside for part of the day to get a good natural breeze and some sunlight.
But, its more likely that you are interested in growing herbs indoors because you want fresh herbs during the winter months and opening a window or putting your precious plants outside is not feasible. In this case, there is a simple solution – a small fan.
Use small fan for air circulation
Simply buy a small oscillating fan or stationary fan and put it on a very low setting to create a breeze for your plants. You need to be careful though as you don’t want a big wind that will blow the plants over. Be sure to place the fan at a distance that will create only a slight breeze on your plants – you don’t want them to be bent down but just gently moving.
If you have an oscillating fan, this is perfect because it will create a varied breeze instead of a steady stream of air. Moving the fan to a different part of the room each day will help create a breeze and provide air circulation from different angles much like the plant would get if it were growing outdoors.
Provide humidity for herbs
If your plants need more humidity, try misting them regularly but be careful not to get them too wet as you don’t want to invite mildew. If you mist your plants and don’t have adequate air flow you will most likely find fungus or mildew growing.
Another thing you can do to make the area around your plants more humid is to rest them in a tray of water. You don’t want the actual bottom of the plant pot to rest in the water though or your plant will draw too much of it up into the soil. The best thing to do is put some pebbles down so that the plant pot itself is not touching the water but the water is in the container around the pot. This way, as the water evaporates up to the side of the pot, it will create a little flow of humidity for the plant.
Most herbs love sunlight and it can be a challenge for you to provide enough of that for your indoor garden, especially if you live in a region where there are short winter days and the sun is very weak.
Since sun-loving herbs often require 6-8 hours each day of sunlight, the indoor herb gardener often needs to use supplemental lighting from artificial sources to keep them growing vigorously.
Growing herbs indoors with artificial light
Low-intensity fluorescent lights have long been used by home gardeners to start seeds and to grow herbs indoors. Standard fluorescent lighting is typically a 4-foot unit with two 40 watt bulbs. Special tubes are used for growing plants or a combination of warm-white and cool-white tubes will work well. Keeping your herbs 6 inches from fluorescent bulbs is recommended if 700-foot candle-power is needed. If you want stronger lighting, high-intensity discharge lamps are available for home use.
These lights work well even if they are farther away from your herbs. High-intensity lamps are recommended for serious herb growers, especially during the winter months when natural light is less intense. The most efficient high-intensity lighting is high-pressure sodium lamps. These bulbs start at 150-watts and go up to 1,000-watts. While high-intensity lighting works the best, it is more expensive to purchase the bulbs and to operate them. Avoid using this type of lighting during peak energy usage hours to keep your electric bill as low as possible.
How much light do indoor herbs need?
No matter which type of herbs you are growing, they must receive at least 6 hours of direct sunlight each day. Herbs that receive high-light, will have noticeably thick and strong leaves. If the amount of light is too low, the leaves will appear thin and delicate.
If you are bringing your herbs indoors for the winter, be aware that many herbs have a difficult time making the transition from the high-light available outdoors, to lower indoor lighting, so you might want to start your indoor garden from scratch.
Allow plants to adjust to lower indoor
Certain types of herbs such as rosemary are especially susceptible to the effects of low indoor light. When bringing your herbs indoors during the winter, it is a good idea to gradually allow the plant to adjust to lower indoor lighting by placing it in partial shade for two weeks before bringing the plant indoors. Move it to even deeper shade for another week before bringing it inside, which gives the plant time to adjust to lower lighting conditions without causing sudden browning, leaf drop, and death.