Indoor herb gardens

Abby sent me these questions about growing herbs indoors. 

I’m wondering about tips for an indoor herb garden.  How much light is required? Which types of herbs are easiest to grow?  How often do the herbs need to be watered?  And most importantly, do I need to worry about my cats eating them?

Here are some tips about growing herbs indoors.

Herbs you can grow indoors are: Annual herbs-parsley, sweet marjoram, basil, anise, coriander; Tender Perennial herbs- scented geraniums, lemon verbena, rosemary; and Perennial herbs- mint, chives, thyme, sage, lemon balm and tarragon. If you had not started the seeds in the summer or have not already brought the herbs into the house from outdoors, you should purchase the herbs as plants so that the plants are well established and happy in the pots that they will grow in over the winter. Otherwise the double shock of transplanting in the fall and bringing the plant indoors might be too much for the herbs to survive. Two good places to buy herbs are Russell Gardens 600 New Road, Churchville, PA 18966; (215) 322-4799; and this site. 

If you do want to try to grow the herbs from seed, the seeds to try are sweet marjoram, parsley,anise, coriander, compact dill, basil and Greek oregano. Be sure to request compact plants because some of the regular plants, like dill, need more room to grow. To start the seeds, just fill each pot with regular potting soil and put the seeds into the soil – the depth will be specified on the seed packet – and mist with water. It’s worth it to buy a mister for this purpose. Keep the pots in a sunny window, and keep the soil damp. Don’t be afraid to mist the soil every day if necessary. This is especially important if you are in an over-heated, dry apartment. Each day, the soil should be damp to the touch, but should not be soaked. Once you see sprouts, be careful not to over water, because over watering can cause the roots to rot.

The growing herbs in your house need LOTS of light. Plenty of light and a minimum of 4-5 hours of sunlight is essential, so the best site for the herbs is in a southern or western exposure. Some people use grow lights to be assured of enough light. You may want to rotate the herb plants once a week to be sure that all the leaves are getting adequate sunlight.  Another suggestion, if you don’t have grow lights, is to place a lamp with a 100-watt bulb or larger near the plants and keep the lamp lit from sunset to about 10pm daily or all day on grey, overcast days.

Herbs like good air circulation and cool nights- preferring 55 degree night temperatures. Keep herbs away from locations in the house where they will experience extremes in temperature; do not put your indoor herb garden right in front of a radiator, the heating vent or right next to the kitchen stove.

Six-inch pots are best. Clay pots are preferred if you potted them up with garden soil because clay pots allow good air and water circulation. If they are in a soil-less rooting medium (a soil-less rooting medium  is a mixture of vermiculite, peat, and perlite. There should be directions on the packages as to how much to use, or you can ask at the greenhouse where you buy the soil-less mixes), plastic pots are better to prevent the plants from drying out too rapidly. But any pot with good drainage will do. Be careful of over watering, especially when the herbs are in plastic pots. It is best to plant each kind of herb in a separate pot so that you know what herb is in each pot. Herbs, when growing, prefer to be kept a little on the dry side- they don’t like to be over watered. Poke the soil with your finger to feel if it is dry and needs watering. But herbs do like sufficient humidity so kitchens can be a good place for them or in other rooms, keep them sitting over, not in, a pebble tray with water. 

For maximum  herb leaf flavor, don’t over-fertilize. Monthly feeding with 1/2 teaspoon of a 20-20-20 water-soluble fertilizer per quart of water is ample for plants growing in soil-less rooting media. If you are growing your herbs in clay pots filled with soil, you do not need to fertilize them at all.

Don’t be afraid of using the herbs for cooking. Snipping the herbs for use in cooking will make your food more exciting and will keep the plants from blooming and turning to seed or getting too large. The more you cut the plants the more they will thrive.

When it is warm enough, in late spring, to take your herbs outdoors, take them outdoors in their pots (or replant them in slightly larger pots) and leave them next to your kitchen door so that you can easily get the herbs to use in cooking. Or you can sink the herb plant while still in its pot into the ground (or repotted in a slightly larger pot). Then in the fall the pot can easily be dug up and brought back into the house for next winter’s kitchen herb garden.

Don’t feel frustrated if your herbs do not do well in your house. Herbs need that proper amount of light/sunlight, warmth in the day and coolness at night, humidity, good air circulation and care. Homes are not really the ideal environment. Rosemary is particularly finicky. But with experience you will learn which herbs thrive for you in your home.

To answer your question about your cat and the herb garden: Cats go crazy for Valerian, catnip or cat mint and certain grasses. You might be able to grow these in your house for your cat; but keep the cat’s herbs away from your culinary herbs. I don’t know how curious your cat is about plants that come into your house, but if your cat starts getting into your culinary herbs, use that mister you bought for your herb seeds and mist your cat. This is a benign way for the cat to learn to stay out of the herbs.