What to plant
Growing Herbs in Raised Beds
Most culinary herbs thrive in a raised bed with 6 to 8 inches of well-drained soil and at least 6 hours of sun. Space small herbs 6 to 12 inches apart, shrubby ones up to 24 inches, and keep mint fenced in.
| Herb | Spacing | Life cycle | Plant out |
|---|---|---|---|
| Basil | 12 in | Annual | 1–2 weeks after last frost |
| Cilantro | 6 in | Annual | Sow 2–3 weeks before last frost; again in late summer |
| Dill | 12 in | Annual | Sow around last frost |
| Parsley | 8–10 in | Biennial | 2–3 weeks before last frost |
| Chives | 8–12 in | Perennial | Around last frost |
| Thyme | 12 in | Perennial | Around last frost |
| Oregano | 12–18 in | Perennial | Around last frost |
| Sage | 18–24 in | Perennial | Around last frost |
| Rosemary | 24 in or more | Tender perennial | After last frost |
When to plant
Herbs fall into two timing groups. Cool-tolerant ones such as parsley, cilantro, dill and chives can be sown or set out a few weeks ahead of the last spring frost. Cilantro bolts fast once days turn hot, so sow a second round about six to eight weeks before your first fall frost for a cooler-weather crop.
Basil and rosemary want warmth. Wait until one to two weeks after the last frost, when nights stay above about 50°F. Cold nights blacken basil leaves and stall it for weeks. Thyme, oregano and sage transplants can go in right around the frost date.
Spacing and depth
Herbs vary from pencil-thin chives to rosemary that can reach 3 feet across in warm climates, so check the table and give each its mature room. A 4x4 section of bed comfortably holds one sage, one rosemary, two thyme, two parsley and a basil or two. Crowding cuts airflow and invites mildew. Annual herbs also tuck well into vegetable beds: basil fits between pepper plants, and chives or parsley make a neat edging along a row of lettuce. Our crop planning guide shows how herbs fit into a whole bed.
Most herbs root shallowly, and 6 to 8 inches of loose soil over dug native ground is enough. Woody perennials you plan to keep for years do better with 10 to 12 inches. Our guide to raised bed depth explains when deeper is worth the extra soil.
Soil and feeding
Herbs from the Mediterranean, like thyme, oregano, sage and rosemary, grew up in lean, gritty ground. Rich soil and heavy fertilizer make them soft and leggy with weaker flavor. Start with a standard raised bed soil mix, then blend extra pine bark fines or perlite into their corner so water drains quickly.
Leafy herbs are hungrier. Basil, parsley and chives appreciate an inch of compost at planting and a light feed of fish emulsion or half-strength balanced fertilizer every four weeks once you start cutting.
Watering
Group herbs by thirst. Let the top inch or two of soil dry between waterings for thyme, sage, oregano and rosemary; wet feet cause root rot faster than drought hurts them. Basil, parsley, cilantro and chives need soil that stays evenly moist, about an inch of water a week and more in heat. A drip line with separate runs, or simply planting the two groups at opposite ends of the bed, makes this easy. More on schedules is in watering raised garden beds.
Crop specifics: perennial vs annual herbs, mint control, harvesting
Perennials and annuals
Thyme, oregano, sage, chives, tarragon and mint come back each spring in most climates. Rosemary survives winter outdoors only in milder regions, roughly zone 7 and warmer depending on variety; elsewhere, grow it in a pot you can bring in. Basil, cilantro and dill finish in one season, and parsley flowers and quits in its second year. Put the perennials at one end of the bed so replanting annuals each spring does not disturb their roots.
Mint control
Mint spreads by underground runners and will fill a bed within a couple of seasons. Plant it in a bottomless 5-gallon pot or a section of pipe sunk into the soil with the rim standing 2 inches above the surface, then snip any stems that root over the edge. Lemon balm is a cousin that spreads mostly by seed, so cut its flowers before they mature.
Harvesting as you go
Regular cutting keeps herbs bushy. Pinch basil just above a pair of leaves and remove flower spikes as they form. Never take more than a third of a plant at once.
Harvest
Cut in the morning after dew dries, when leaf oils are strongest. Use scissors on soft herbs and pruners on woody stems, leaving green growth behind; woody herbs rarely regrow from bare wood. Stop heavy cutting of sage, thyme and rosemary about a month before your first fall frost so new shoots can harden. For drying, bundle stems loosely and hang them out of direct sun, or freeze chopped basil and parsley in a little oil.
Common problems
Basil leaves yellowing with gray fuzz underneath
That is basil downy mildew. Pull affected plants, give the next ones more space and choose resistant varieties.
Rosemary or lavender turning brown
Usually soggy roots. Add grit to the soil, water less often and keep mulch away from the stems.
Cilantro flowering early
Heat and long days trigger bolting. Sow small batches in spring and late summer, and let a few go to seed for coriander.
Thyme gone woody and bare
Older thyme thins out in the center. Trim lightly after flowering and replace plants every three or four years.