Most herbs worship the sun! As transplants from the Mediterranean, herbs do not take kindly to being grown in environments that do not replicate their origins, or in areas with less than sufficient sunlight, such as inside houses. Herbs do not thrive in east, or north facing windows, as these sides of the house seldom see adequate sunlight.
Let There be Light:
Even if you can arrange your herb gardens in windowsills that face south or west, and your plants are getting the required 4 hours of sunlight a day minimum, it is advisable to provide additional supplementary lighting. Choose grow lights designed specifically for indoor herb gardens; the light intensity needs to be good and strong, and the light spectrum needs to be right as well.
Plants can produce two types of leaves, depending on the quality of light they receive. Leaves that get an abundance of good, strong light in the proper spectrum, will be strong, thick and narrow. Leaves that do not receive enough light, or light from the wrong spectrum, will be weak, thin and broad. Narrow leaves are less efficient at converting the light source into plant food than the broader leaves. If a plant gets accustomed to receiving ample sources of adequate light it can turn brown and shed leaves during indoor growth cycles. This happens due to the fact the plant is incapable of making enough food to survive. In response to this condition the plant will shed the lower inefficient leaves and sprout newer, more efficient leaves at the top of the plant, closest to the light source. If you bring herbs indoors to grow, this shedding of leaves and lengthy growth cycle can occur in a matter of days, or even within a week or two. Some varieties of herbs are incapable of making the transition from outdoors to indoors.
Rosemary provide a prime example of this condition. As an herb, rosemary grows very slowly, stifling the opportunity for the plant to make the necessary changes to the light it receives. One of the greatest complaints about growing rosemary indoors is the sudden and immediate death of the plant. To prevent this from happening, simply adjust the type of light the herb is receiving while still outdoors. Put it in a slightly shaded area approximately 6 weeks before bringing them indoors. Three weeks before bringing them indoors move them again, this time to an area with even more shade. This will allow them to gradually adapt to the lower light conditions they will be receiving once moved indoors and placed in an appropriate windowsill. When new growth starts to show, your plant is ready to make the transition to its indoor growing location.
Water, Soil & Fertilizer:
Soil condition is the second most important factor when growing herbs indoors. Herbs prefer a growing medium with above average drainage. Most herbs produce their best when grown in soil with pH levels around 6 or 7. We recommend combining a good compost based soil mixture with perlite and sand, as this will produce the drainage most herbs require when grown inside.
Herbs produce the best flavor when grown outdoors under optimum conditions. When grown indoors, your herbs will require supplementary feedings. We recommend using an organic fish emulsion once a week during the active growth cycle. If the plants are dormant, do not feed them!
Herbs do not require an abundance of water, nor do they necessarily prefer moisture at all times. We recommend watering them once a week when the soil is dry, rather than overwatering them. Once the soil is dry, water the herbs until it begins dripping out of the drainage holes on the bottom of the pot/flat. If water doesn’t drip through, there is a problem with the condition of the soil, or a blockage that needs to be removed. Consider replanting them in soil with better drainage.
Are you growing an herb garden indoors this winter? Drop a comment below and let us know how the garden is growing and share any helpful hints, tips, and tricks you might have. We would love to hear from you!