This is the most important task in the herb garden in spring. Early spring is the best time for sowing seeds of hardy annuals and perennials that are easy to grow from seeds, in trays in a cold greenhouse. Annuals that can be sown in early sprig are: borage, summer savory and pot marigold. You can also sow parsley now if you can provide constant heat for germination. Perennials that can be sown now include: fennel, sage, pot marjoram, winter savory, horehound, common thyme and wild thyme. Basil, sweet marjoram, nasturtium and any other herbs that dislike being transplanted like: dill, chervil and coriander, will be sown only in late spring, when they can be grown directly outside. Also hardy annuals and perennials that are easy to be raised from seeds should only be sown outdoors in late spring, when the soil has warmed up.
The rest of the herbs that cannot be raised from seeds should be propagated by vegetative methods like: root cuttings, layering or division. Herbs that can be propagated from root cuttings in spring include: mint, tarragon, bergamot and chamomile and they do not need any extra heat. Thyme and sage can be propagated by layering. Mound up earth around them to encourage new shoots or bed a single branch into soil until it roots to form a new plant. Herbaceous herbs and fibrous-rooted ones can be divided all spring long to make new plants.
Seedlings that were raised in trays will have to be pricked out and potted separately into 7.5 cm pots so they can develop and harden off before they are finally planted out in the garden when all the risks of frost have passed. Seedlings that were grown directly outdoors need to be thinned out so that the plants left to have enough space to grow. Plant out pot-grown herbs that you have bought from the nursery once the weather has warmed up a little and the soil is still moist.
Keep your herb garden in good shape by hoeing weeds and any unwanted plants out of the paths and beds immediately as they appear as this way will be much easier to control them. If you hoe them as they appear they will not be allowed to set seeds or to grow too big and kill your herbs. You can also suppress weeds and conserve moisture around the plants by spreading now a layer of mulch around your herbs. The mulch is most effective when the soil is damp.
Prepare the soil
Spring is the time for you to prepare the beds for planting by forking over and incorporating lots of garden compost or some slow-release fertilizer. If your garden soil is heavy you have to improve it by digging in manure or bulky organic material.
Pruning is an essential task that need to b done in the herb garden in order to stimulate new growths, but be careful not to start pruning hard too early in the spring when frosts are still likely to come because the new growths that will appear will be injured or killed by frost. Once the weather is suitable and all risks of frost have passed you can start pruning back to new shoots the shrubs and silvery herbs that have suffered winter damage. Cut out dead and straggly growth on sage and thyme but trim thyme only lightly after flowering as they do not respond well to hard pruning. You can cut back hard rosemary but leave it until it has flowered. Trim box hedges, bay and all formal topiary shapes.
Herbs in containers
Keep in shape the herbs that you are growing in containers by trimming out any dead or old growth. Start to give them more water as the weather is getting warmer and give them a liquid feed once the new growths appear. If necessary you can replant them now into larger pots with fresh growing compost.