AMES, Iowa – While the weather is cold outside, you can still cook fresh herbs. If you take advantage of the sunny window in your home, herbs can bloom all year round. In this article, Iowa State University Extension and Outreach gardeners answer questions about growing herbs indoors.
Which herbs are best for indoor cultivation?
Almost every herb has the potential for indoor cultivation. However, there are species that perform better under indoor growing conditions. These herbs tolerate lower light levels, low humidity and cooler indoor temperatures, making them the best herbs for growing herbs at home. Parsley, mint, chives, basil, oregano, coriander and thyme are all great for indoor cultivation. Although still relatively easy to grow inside, rosemary, sage, lemongrass, marjoram, cherries and laurel laurels are good species to try next time.
What cultivation conditions are best for indoor herbs?
Light is typically the most limiting factor in the successful indoor cultivation of herbs. Plants will need as much direct sunlight as you can. Most herbs need about eight hours a day of direct light when grown indoors. A south-facing sunny window is a great choice, but a bright east- or west-facing window can also be good.
The typical indoor temperature is ideal for herbs. Allow the soil to dry between each watering, as most herbs do not tolerate moist soil. Tanks must be the correct size. Too big ones stay wet for too long. Containers should have good drainage with a well-drained flowerpot mixture. Clay or terracotta pots are great choices for herbs because they are porous and dry more easily. Grow all types of herbs in their own pots, as it is difficult to create the best growing conditions for several types of herbs in a single pot.
Herbs do not require as much fertilizer as other container plants, but are good for intermittent light fertilization with a balanced, universal fertilizer solution at half or quarter strength. Fertilize in early spring through summer and avoid fertilizing during the winter months.
How can I provide more light to my herbs?
It is difficult to provide enough light for the indoor growth of herbs, especially during the winter months when the days are shorter. Some herbs tolerate up to six hours a day in direct light, but most want eight hours or more a day. If the light level is inadequate, the herbs will develop well under additional lighting.
Small, lightweight equipment is available from many online retailers and garden centers. Gardeners can also create their own growing light setting. These can range from compact fluorescent bulbs in a luminaire designed for a few plants, to a pluggable 4-meter LED shop light for larger herbal collections. Look for full-spectrum ascending lamps in high-performance luminaires. For greater light intensity, place the lamps 6 to 12 inches away from the leaves. Connect the lamp to a timer that runs for 12-16 hours a day for ideal growth.
How can I harvest and use indoor herbs?
Harvest the herbs indoors as you would grow them outdoors. Most are good at intermittent slaughter because they are needed in the kitchen. Leafy annual herbs such as basil, cherries and parsley can be strongly cut back at harvest. Use a sharp knife or pruning shears to cut directly over a leaf or pair of leaves. Leave about 4-6 inches from the stem for later growth. Do not cut back leafy perennial herbs as hard as annual herbs. On perennials such as chives, mint, oregano, and thyme, remove the top third of the growth.
After several harvests, it is advisable to discard the old annual herbs and start new plants from seed. After the threat of frost in the spring, perennial and young perennial herbs such as rosemary, laurel and marjoram can be placed outdoors, where harvesting can continue throughout the summer.
Will indoor herbs taste the same as those grown outdoors?
Many indoor herbs do not taste as strong or as intense as those grown outdoors. However, my basil will always taste the same as basil, whether grown indoors or outdoors.
Photo to share: Indoor herbs.