A summer herb garden produces more than most people can use fresh. The difference between a productive herb garden and an overwhelming one is knowing how to preserve the surplus. Different herbs require different preservation methods — what works brilliantly for rosemary is disastrous for basil.
Drying
Drying works best for herbs with lower moisture content and robust volatile oils — rosemary, thyme, oregano, sage, bay, and lavender all dry excellently and retain strong flavour. Harvest stems in the morning after the dew has dried but before the heat of the day drives off volatile oils. Tie in small bundles and hang upside down in a warm, dark, well-ventilated space. Good airflow is essential — stagnant air causes mould. Most herbs dry completely in one to three weeks depending on stem thickness and ambient humidity. Once dry and crumbly, strip leaves from stems and store in airtight glass jars away from light and heat.
Drying in an Oven or Dehydrator
An oven on its lowest setting (50-60C, or 120-140F) with the door propped open for airflow dries herbs in two to four hours. A food dehydrator gives more consistent results at lower temperatures. This method works for all dryable herbs and for large quantities when air drying is slow. Avoid microwave drying — it strips flavour and produces uneven results.
Freezing
Freezing is the best preservation method for soft, high-moisture herbs — basil, parsley, coriander, chives, dill, and tarragon. These herbs lose almost all their texture when frozen (making them unusable as fresh garnishes), but their flavour is largely preserved and they work perfectly in cooked dishes. The simplest method: blend fresh herb leaves with olive oil and freeze in ice cube trays. Once frozen, pop the cubes out and store in a labelled freezer bag. One cube equals approximately one tablespoon of fresh herb.
Herbed Oils and Vinegars
Infused oils and vinegars preserve herb flavour in a useful, long-lasting medium. Use dried herbs (not fresh — moisture in fresh herbs encourages botulism risk in anaerobic oil) to infuse into warmed oil. Steep for one to two weeks, then strain and store in sterilised bottles away from light. Herbed vinegars can use fresh or dried herbs — fill a sterilised jar with herb sprigs, cover with white wine or apple cider vinegar, and steep for two to four weeks. Both keep for three to twelve months.
Herb Salts and Sugars
Blending herbs with salt or sugar creates a versatile condiment that lasts indefinitely. Mix fresh or dry herbs with coarse salt in a food processor, then spread on a baking sheet and dry in a low oven before storing. Herb sugars work the same way with soft herbs like lavender, lemon verbena, and rose petals. Both make excellent cooking ingredients and gifts.
FAQ
Can I dry basil?
Basil can be dried, but it loses most of its characteristic fresh flavour in the process. Freezing in oil is far superior for preserving basil character. If you must dry it, do so quickly at low oven temperature — air drying in humid conditions produces mouldy, flavourless results.
How long do dried herbs last?
Whole dried leaves in an airtight jar away from light last 1-2 years. Ground or crumbled herbs lose flavour faster — 6-12 months. A rough test: if the herb smells faintly or not at all, it has lost its potency and should be replaced.
Do frozen herbs need to be blanched first?
Not for herbs that will be used in cooking. Blanching destroys some volatile oils and is unnecessary for the ice-cube-in-oil method. Blanching is useful if you want to freeze whole leaves for appearance in drinks (ice cubes with herb sprigs) but not for flavour preservation in cooking.
Is it safe to make herb-infused oil?
Using dried herbs is safe. Using fresh herbs in oil creates an anaerobic environment that can support Clostridium botulinum growth — refrigerate fresh herb oils and use within one week. Dried herb oils are shelf-stable for months.
What is the best herb to grow specifically for drying?
Oregano, rosemary, and thyme are the most practical choices — they dry easily, retain strong flavour, and are heavily used in cooking throughout the year. Bay leaves air-dry on the branch and are worth growing for the year-round supply alone.
See also: Best Herbs for Small Raised Beds and How to Grow Basil: The Complete Guide.