Growing Herbs Indoors
This time of year, we get lots of questions about growing herbs indoors. Growing herbs is easy and fun to do but it can be a challenge to do indoors. You may not be successful growing all of the herbs during the entire winter season but try to think of it as a short term extension of the garden and see what works well in your indoor climate. Most kitchens will have enough light but there are a few that just cannot grow anything but African Violets, don't try to grow herbs under very low light conditions without a bright growing fluorescent light fixture. Special bulbs are available which give off the full spectrum light and helps with the overall quantity of light. These are not enough on their own but a window even one shaded by trees can still be bright enough when supplemented by the grow light. Find a window located on the south or west side that captures the most light possible. Sunrooms and Greenhouse type windows are other alternatives which work great.
Keep in mind that in order for the herbs to actually grow, as opposed to going dormant, you will need to keep them warm as well as sunny. Don’t worry about trying to grow Sweet Basil during the middle of January but you can have it last into December and then start again early in March. Make sure you do not place the herbs near heating ducts or fireplaces as they can really dry out the leaves even though you water them frequently.
Large pots are crucial, 8-10" pots seem to do best for long term growth. Those cute little pots marked with the name of the herbs are very short term. Drainage is also important so watch for trays that catch water and keep the roots wet all the time. Your plants will not appreciate the wet feet. Rosemary, Thyme, Sage and Oregano must have a period of dry soil before they are watered again so make sure the soil gets dry most of the way down by only watering when the soil is very dry to the touch. Overwatering is the number 1 killer of indoor herbs. You can add gravel to trays or saucers and fill them with water for humidity, or mist the leaves of the plant once a week with a spray bottle. Pick your herbs frequently as it stimulates new growth but limit your cuttings to very small amounts, you don't want to cut too much of the plant away at one time.
There are a few indoor pests that bother herbs in wintertime, mostly fungus gnats and whiteflies which need to be treated with soapy water. Fungus gnats can be a problem since they live in the soil. The best thing to do is to try to remove the top 1/2" or so of soil and replace it with fresh. If you still have a problem, drench the pot with soapy dishwater. That should get rid of them but if not, you can purchase Safer soap or some of our Neem II and spray the soil with that. It may take a couple of treatments with the soap. Also, let the soil dry out almost completely before watering again, that seems to discourage them. Whiteflies should be sprayed with Neem II or sprayed with soapy water making sure to get the soap actually on the flies to kill them.Fertilizer is hardly needed at all during the winter, only use some good compost or Worm Castings in the soil mix when you plant and add it again to the top of the soil about half way through the season. Good luck!