Most herb aficionados agree that fresh grown herbs are much better than dried or anything purchased. However, winter tends to put a cramp in what can be grown outside. Take heart; there are a number of culinary herbs that can be easily grown inside with a little effort.
When growing herbs indoors, it is necessary to choose ones that will grow in smaller spaces and without full sunlight. Chives, parsley, thyme, basil, sage, winter savory, lemon balm, and oregano would all fit the bill. Most will stay less than a foot tall; the taller ones can be still grown if a dwarf variety is chosen.
Although when grown outside, herbs do well in poor soil, choose a good quality potting soil when growing them inside. Make sure the pots have good drainage; six inch pots are a nice size for most herbs. Water when they start to dry out, but do not keep them moist all of the time. Herbs do not like to have wet feet. Grouping the pots together will raise the humidity, however do not place them so closely that air cannot circulate. This will promote mildew and disease. If mildew starts to form, separate the plants a bit and put a small fan in the area to circulate the air.
Most culinary herbs are native to the Mediterranean area. They require full sunlight to thrive. When growing them inside, make sure they have 6 hours of sunlight by putting them in a south window. If that is unavailable, place them six to twelve inches from two 40-watt cool white fluorescent bulbs for 14 to 16 hours. Without adequate light, plants will become leggy and spindly. If grown on a sunny windowsill, rotate the plants periodically to make sure to get uniform growth on all sides.
Herbs enjoy the same temperatures indoors that people do. They like daytime temperatures of 70 to 75° and most can tolerate nighttime drops to 55 to 60°. Most herbs can withstand temperatures as low as 40°, although most people would not. Basil would be the exception; it does not survive anything less than 50°. Therefore, be careful about putting it too close to a cold window where the temperature may drop at night.
Because potting soil lacks any significant source of nutrients, herbs will benefit from a low dose of water soluble fertilizer every 2 to 4 weeks. Fertilizing any more frequently will result in an off flavor and reduction of aroma.
Herbs kept inside for any length of time will invariably attract pests. They are easily controlled by spraying with a soapy solution. Use 1 to 2 tablespoons of a mild dish detergent in a gallon of water and spray the plants weekly while the pests are visible. If the leaves show discoloration, reduce the amount of soap.
Harvest the herbs as needed. Frequent cuttings will help keep the plant stocky and compact. Leave a few inches at the stem for regrowth.
If this is a first-time indoor growing experience, the easiest one to start with is chives. Not only are they easy to grow, they are versatile and can be used in every meal from breakfast to dinner. If a challenge is the desire, go for basil. It is great to cook with, but tougher to grow indoors.
Happy gardening and happy cooking.
Certified Master Gardener