Winter herb plant care begins long before winter arrives. A few weeks ago I was tending the herbs. Another year of growing beautiful, useful medicinal and culinary herbs. I picked off leaves that had fallen from the trees and checked to see if they needed water. I don’t plan to leave them outside to wither and die for the year. Some are perennials and others are annuals. Even the annuals were still so healthy. I will re-pot at least a portion of each plant and care for the perennial herbs through the winter. This has been my method for the last few years. It gives my herb garden a jump start in the spring, as many plants are already forming new growth. And, it gives me a ready source of fresh herbs over the winter.
The large lavender bushes in one garden stay outside, as does the well established sage bush. I trim them down low, cover with leaves and let them rest. Clustering some of your perennial potted herbs and covering with leaves or even an old sheet, will help them remain hardy throughout the winter.
I also left some of the hardy mint plants in the garden. It’s hard to kill mint, although I have done it before. I brought in some cuttings from the chocolate mint, the spearmint and the peppermint to enjoy fresh mint all winter long. The mint will return in the spring as the ground warms. All the plants get a good haircut!
When to bring them inside
When we bring plants out in the spring, we practice what is called hardening off. Gradually acclimating the plant to the outside temperatures by choosing warm spring days with good weather, in a sheltered area. The same is true of winter herb plant care for the cold weather. Before cold weather is even an issue, I make decisions on which potted plants will come back inside. The others will be trimmed down and covered with leaf mulch, allowing them to rest for the winter.
Winter Herb Plant Care
The potted herbs that will over winter in the glass enclosed porch, are gathered closer to the house. They are trimmed, and inspected for insects. You don’t want to bring ants or other crawly life into your home! As the weather begins to grow chilly, the pots are placed on the back porch. They can still get plenty of sun, but they are protected from any colder winds and heavy rains.
Before any serious frost, the potted herbs move once more, to their winter home. If we didn’t have this glass enclosed porch, I would place them in a sunny window area. Our porch does not protect them from the very coldest of temperatures. But most of the winter the plants do very well and receive plenty of sunlight.
When our outside temperatures drop to the teens and lower, I do need to give the herbs a little more care. Last year, during any extreme cold spells (for our area) I covered the plants with sheets of newspaper and placed more newspaper between the plants and the window. This worked to keep frost damage from occurring. If you try this, take the newspaper off during the warmer daytime. The newspaper might become damp from condensation. In that case, replace it with dry newspaper.
How much to water indoor herbs
Herbs like a drink. They do not like to have soggy feet. When carrying out winter herb plant care, make sure the top of the soil feels completely dry. Water the plant but do not soak it deeply. Keep in mind that the plants are in a resting phase, although still alive and possibly showing some growth. Over watering will kill the plant. I checked weekly but did not water weekly.
Should you still cut from the plants?
It is fine to use the plants as needed for cooking or other needs. I doubt you will see enough growth to actually harvest a large amount. But using the herbs fresh, as you need them, is perfectly fine.
Grow from seeds to transplant later
If you didn’t grow herbs outside this summer, fall is a good time to start an indoor herb garden from seeds. For a new indoor garden, keep the pots inside the warmer area of the house, water carefully as needed.
Herbs that Over Winter Easily Indoors
Even though many of these would do fine staying outside, bringing in a small pot of these gives me a ready source of fresh herbs during the winter, for cooking and medicine making. Sage, mint, lemon balm, lavender and chives would return in the spring if left outdoors.
What to do for Perennial Herbs Left Outside
Some of my larger perennial herb plants have grown past the point of coming indoors for winter. If we are going to have extremely cold weather I sometimes move the containers closer to the back door or simply cover the pots with a tarp. I don’t know if this is even necessary because these few large perennials seem to flourish no matter what I do. The lavender, sage, lemon balm, lemon grass, and mint are trimmed down to just a few inches above ground level. Each year they greet me in the spring with new growth. After a few years in the same container, my large sage and largest lemon balm are going to need to be repotted next spring. For me, winter herb plant care is just part of my whole plan for growing delicious, healthy herbs. In the meantime, sleep well herbs.
I live in southern Ontario, our winters are sub-zero on the regular. In zones warmer than 6, you can overwinter most of these herbs if planted in the ground. Basil is intolerant to cold and I’ve seen the leaves blacken with cold temperatures, even without frost- it invariably dies if left out in winter. Rosemary is a tender perennial that I pot up to bring inside and lavender can be a little tender for my region if we have a harsh winter but will often fair better during extreme cold weather if planted close to the foundation of the house. All the others you’ve listed will survive winters in the ground in my zone 6 region. The only maintenance I do for these is pruning for plant shape and to improve overall health and potting up some for indoor use throughout the winter as you describe.