Baby It’s Cold Outside …

By Paris Wolfe, Blogmaster, The Herb Society of America

Did you bring herbs into your house for winter? How do they look? It may be discouraging if you’re in Northeast Ohio like I am. But, leggy or slowly fading herbs aren’t your fault.  And, there may be hope. Operative word: “May.”

The indoor herb garden requires extra effort in colder climates, according to Karen Kennedy, education coordinator for The Herb Society of America. By extra effort, she means supplemental light and attentive watering.

Briscoe White, co-founder and head grower at The Growers Exchange, an all-natural, online garden center that specializes in rare and traditional herb plants for culinary, aromatic and medicinal use, says,   “Most herbs require six to eight hours of sunlight per day. We recommend an unobstructed, southwest or east-facing window.”

And, that’s more likely in areas further south.  In growing zones six and seven, winter sunshine can be elusive. In fact, if sun powers the plant’s energy production, imagine reducing that power 78 percent, from nine hours per day in July to roughly two hours per day in January. Not only do days get shorter in Northeast Ohio, actual sun siting dwindles.  Less sunlight means reduced photosynthesis and sun-loving herb plants starve.

rosemary-winterSo, what might look like success in October and November, could fail in January and February. That’s fine, if you have Kennedy’s expectations. “My goal is to keep some herbs alive through the holidays, when I use it most,” she says of rosemary.

Post-holiday success is when modern light sources become important. That’s because traditional incandescent lighting is too hot and lacks the blue rays that plants need to move electrons and produce their own food. Grow lights, most often fluorescent, can supply the right waves.  But, even then the precious light must be within inches of the green, and so the bulbs must be elevated gradually as the plant grows taller.

Over the years I’ve found that bay trees are the most likely herb to survive a Northeast Ohio winter indoors without a grow light, while basil, a hot weather annual, is least likely. Still, with careful coaxing by grow light, Kennedy has nurtured enough basil for a caprese salad in February.

Skeptical of the effort, White suggests buying this gift of summer from a grocer during the snowy, cold winter days. And, Kennedy says it’s unlikely to take root in a pot from the living plug sold at the store. So, keep your expectations low if you decide to try.

White offers tips to help your indoor herb garden succeed

  1. Find a permanent location, somewhere away from hustle and bustle of socializing, kids, and pets. Moving plants often can unsettle their soil and root structure, and weaken them.

  2. Locate away from cold drafts or hot air vents. Avoid dry air by either misting plants regularly or by filling the drainage tray with pebbles and adding water.

  3. Move plants into a brighter window if top growth gets leggy and thin. If you can’t, then pinch the ends to encourage bushier growth.

  4. Turn herb plants regularly so that all sides are evenly exposed to light.

  5. Clean tops and bottoms of leaves with a damp cloth to remove unwanted dust buildup or insect eggs that may hinder health.

  6. Remove pests with a mild soap solution. For a difficult infestation, try an all-natural pesticide or fungicide.

  7. Water with a weak but regular application of soluble fertilizer, but not if dormant. Too much fertilizer will decrease oil production. That means less flavor and aroma.


Don’t restrict yourself to nurturing last year’s plants to keep summer alive throughout the year. You can treat yourself to a pot from the Grower’s Exchange and enjoy it while it lasts. Many herbs can be started indoors in winter and transplanted outdoors in spring. Get seed catalogs and start dreaming.

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