Best Way to Care for Herbs

The key to producing healthy herbs — or any other plants — is looking after the soil. Be sure to feed it regularly with organic matter such as compost or manure to replenish it with the nutrients it needs to feed the plants. Herbs are fairly easy to feed, since most of them need less fertilizer than other plants; spreading about 2.5 cm (1 inch) of compost over the soil each year provides all the nutrients that most herbs need. Those described as needing rich soil benefit from extra compost at some point in the growing season; alternatively, feed them with fertilizer at half the strength recommended on the product label.

During the growing season, in a formal garden, herb hedges will need to be clipped. Fast-growing herbs such as costmary and tansy may need to be pruned to keep them under control. Even in an informal garden, sprawling herbs may require occasional trimming. You may need to remove any unwanted self-seeders. Deadheading flowering herbs (removing the faded blooms) will encourage fresh growth and more flowers, but do not deadhead if you want to harvest the seed heads. Invasive spreading herbs such as mints can form dense mats of roots and take over the garden, but you can contain their vigorous roots by planting the herb in a large pot and sinking the container up to rim level in the ground.

Before the first frosts, bring tender herbs indoors or into the greenhouse for winter. Cut down herbaceous perennials once frost has killed back their foliage; wait until spring to cut back silver-leaved and evergreen plants. After a couple of heavy frosts, mulch loosely with straw to protect plants from alternate freezing and thawing of the soil, which pushes them out of the ground. Where the ground freezes during the winter, provide additional protection for marginally hardy herbs by covering with extra straw or a couple of evergreen branches. If you experience problems with winter survival of herbs that are supposed to be hardy in your climate, try improving soil drainage – for example, by building a raised bed. Many herbs do well in dry conditions, and even those that like moist soil usually prefer it to be well-drained. In fact, poor drainage over winter is fatal to many herbs, especially those that have grey to silver leaves.