Now that the days are getting shorter and cooler, it’s time to think about bringing some herbs inside for the winter. What herbs make the best candidates for coming inside? I bring in tender plants that would not survive outdoors such as rosemary and lemon verbena. I also bring in the fresh herbs I like for cooking, parsley, mint and if I have enough room, some thyme. Thyme, sage, and oregano dry well and maintain their flavour so there is less need for fresh plants indoors. These three herbs survive well in our zone 5 gardens.
Before bringing plants indoors, check for insects and diseases. Dig up the plant or remove it from its existing pot. Most herbs will be pot bound if they have been growing in a pot all summer. You may need to score the root ball and tease the roots out. If it has been growing in the garden and is going into a small pot to come inside you may need to prune the roots and trim some foliage to help it fit into its new pot. Remove most of the existing soil and repot using fresh potting soil.
You will need a sunny window or a grow light to successfully grow herbs indoors. They require at least six hours of sunlight. I keep my herbs in our cool basement under grow lights on a timer where they receive 10 hours of light a day. In this cool environment plants need less water than they would in a sunny window in a warm room. Our homes tend to be dry in winter. If you are growing herbs in a warm dry environment you may need to increase the humidity by setting your pots on a tray of gravel filled with water. Make sure your pots are never left in standing water.
It always helps to know something about the plant you are tending. For years, I failed to successfully over-winter lemon verbena. I watched as it dropped all its leaves and became a pot of dried sticks. One year, I stumbled upon an article that mentioned that lemon verbena is actually deciduous. The next year when the plant dropped its leaves instead of tossing it into the compost, I waited giving it minimal watering in its dormant state. When the days started to lengthen, sure enough the sticks started sprouting new leaves. As the leaves grew, I increased the amount of water but allowed the plant to dry out between waterings. I’ve now had the same lemon verbena plant for several years.
Rosemary is a Mediterranean plant. It needs lots of light and good air circulation to avoid getting powdery mildew. It’s important not to overwater. Too wet seems to be more problematic than too dry but it’s best not to let the plant dry out completely. A great herb for flavouring soups, stews or with poultry or meat.
Parsley is a biennial, which means it takes two years to complete its biological cycle. There is no point in taking your old plant back outdoors in the spring because it is more interested in setting seed than in creating tasty leafy foliage. I bring in one pot of parsley for the winter but when it starts to dwindle after a few months, I start a new pot from seed.
Divide the plant and bring a portion indoors. Mint is a vigorous plant that adapts well to its indoor environment. Lots of light and regular watering will keep it thriving through the winter.
What about other favourites such as basil, cilantro, and dill? These are annuals best grown from seed. I usually wait until the longer days of spring before starting these seedlings or simply wait a little longer until I can direct sew them in the garden.
Submitted by Nancy Burnett