You can’t bottle sunshine, but with special care you can bring its vigor into your house during the long dormant season. Check the calendar — fall is here, but that doesn’t mean your gardening time has to end.
Overwintering perennial herbs — such as rosemary and thyme — are a multifunctional and fun way to tap warm weather vitality by boosting your spirit and pleasing the palate.
But, it’s not as easy bringing pots inside. The indoor herb garden requires extra effort in Northeast Ohio, according to Karen Kennedy, education coordinator for The Herb Society of America, based in Kirtland. Extra effort means providing supplemental light and attentive watering.
LIGHT, LIGHT AND MORE LIGHT
“Most herbs require six to eight hours of sunlight per day,” says Briscoe White, co-founder and head grower at The Growers Exchange, an all-natural, online garden center in Virginia that specializes in rare and traditional herb plants for culinary, aromatic and medicinal use. “We recommend an unobstructed, southwest or east-facing window.”
That advice is more likely to succeed in areas further south. In Northeast Ohio, growing zones 6 and 7, 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 strength dwindles. Less sunlight means reduced photosynthesis, and sun-loving herb plants starve.
So, 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 it 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.
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 LivingPlug root sold at the store. Keep expectations low if you decide to try it.
White offers these tips to help your indoor herb garden succeed.
1
Find a permanent location, somewhere away from the 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.
8
Give herbs plenty of room to grow by repotting during winter when cool temperatures are less stressful.
