Grow herbs indoors all winter

By Jim Janke | Aug 04, 2014

Local gardens are at their peak, producing lots of tasty veggies and gorgeous flowers. And that makes gardeners happy. But a few months from now the season will be over and those smiles will turn to frowns, or worse. So here’s a cure for the winter gardening blues: Grow your favorite herbs indoors until you can resume harvesting outside next year. Growing herbs indoors is easy, whether you start plants from seeds, rooted cuttings, or divide existing plants. Here are some hints for popular herbs (but don’t limit yourself to this list!)

Start seeds indoors. Sow basil seeds in early September, and transplant to individual pots three to four weeks after germination.  Small-leafed varieties like ‘Spicy Globe’ or ‘Boxwood’ will stay compact a lot longer than large-leafed types. Sow dill at the same time, and every 6 weeks thereafter for a continuous crop. In early October, soak parsley seeds for about a week before planting, then after the second sets of leaves appear, transplant a couple of seedlings to a 6 or 8 inch pot. Flat leafed varieties grow quicker but get leggy sooner than curly types.

Rooted cuttings. In August, cut 3 to 4 inch tender growing tips of herbs like oregano, rosemary, sage and thyme. Remove all but the top group of leaves, dip the cuttings in a rooting hormone, and stick into a soilless planting mix. Cover with clear plastic to keep moist, and place in a tray with a little water. A few weeks later when good roots have appeared transplant to larger pots.

Divide existing plants. In August divide any healthy perennial herb (like sage, chives, thyme, and mint) to get a golf-ball or larger size root mass. Wash most or all of the soil from the roots, remove the bottom half of the leaves, and plant in potting soil or a soilless planting mix (but not soil from the garden.) To acclimatize the plants to their life indoors keep them in a brightly lit but enclosed area (like a garage window or enclosed porch) for a couple of weeks, then bring them into the house.

Grow where there is adequate light. All these herbs like full sun, but will also grow in an east or west-facing window. Growing under fluorescent lights will make the plants fuller and more compact. Avoid too much heat — most herbs like cooler room temperatures, and actually prefer nighttime temperatures 10 degrees lower. Water regularly, but don’t allow them to get wet feet. Heated indoor rooms in winter tend to get quite dry, so place a shallow dish of water with stones in it amongst the herbs to keep the humidity up.

Watch for insects. You don’t want to bring insects indoors, so closely inspect cuttings and divisions. If you see bugs, knock them off with a stream of water. Or spray with insecticidal soap, making sure to hit all plant surfaces. After a few days rinse off the soap and dead bugs, and only then bring the plant inside.

Container options. Plastic containers will hold moisture better than clay pots. A window box can make a great herb garden — Grow the plants in individual pots that can be turned so they get an even amount of light on all sides, or replaced when necessary without disturbing other plants.

Don’t forget to grow a few extra plants; they make excellent mid-winter hostess gifts.

Jim Janke is an Extension Master Gardener volunteer in Haywood County. For more information, call the Haywood County Extension Center at 456-3575. © 2014 NC State University.

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