Growing herbs in small urban gardens

Why herbs are the perfect crop for tight urban spaces

If you have a courtyard the size of a doormat, a north-facing balcony, or nothing more than a windowsill and a bit of pavement, herbs are the most rewarding thing you can grow. They are compact, they earn their keep in the kitchen, and most of them positively thrive on a bit of neglect. A single supermarket bunch of basil or coriander costs the same as a packet of seed that will keep you in leaves for months, and nothing lifts a midweek dinner like a handful of fresh parsley snipped from a pot by the back door.

The trick in Britain is choosing varieties that suit our weather rather than fighting it. Our summers are rarely hot enough for the Mediterranean herbs to sulk, and our winters are mild enough that many of them sail through outdoors in a sheltered spot. Get the basics right and you will be picking fresh leaves from March to November, with a little extra through the coldest weeks.

Pick herbs that match your light and your patience

Before you buy anything, watch your space for a day. Most culinary herbs want at least four to six hours of direct sun, but a good number will manage in partial shade, which is useful news for the many urban gardens facing the wrong way.

• Full sun, hot spots: rosemary, thyme, oregano, sage, winter savoury and lavender. These are drought-tolerant, hate wet feet, and will reward a south-facing wall.
• Partial shade: parsley, chives, mint, sorrel, chervil and lovage. Ideal for a shady courtyard or a north-east facing window box.
• Sheltered and warm: basil. Treat it as a tender annual in the UK, grow it in a pot on a sunny kitchen windowsill, and it will crop for months.
• Quick and forgiving: mint and chives. Almost impossible to kill, which makes them perfect for a first attempt.

One word of warning: always plant mint in its own pot. Left to its own devices it will send runners through every container on the patio and reduce your carefully planned display to a mint plantation.

Containers, window boxes and the compost that matters

Size is everything. A 30 cm pot holds a decent rosemary or bay; a window box wants to be at least 20 cm deep with a good 6 to 8 litres of compost per metre of length. Terracotta looks lovely and dries out fast, so if you are out at work all day, glazed pots or plastic liners will save you endless watering.

Use a peat-free multi-purpose compost for leafy herbs, and mix in a couple of handfuls of grit or horticultural sand for the woody Mediterranean types. Good drainage is the single biggest factor in keeping thyme and rosemary alive through a wet British winter — they rot long before they freeze. Every container needs drainage holes, and it is worth standing pots on feet or broken tiles so water cannot pool underneath.

If you have a tiny bed rather than pots, dig in plenty of garden compost and raise the planting area slightly so it does not sit waterlogged. Chives, parsley and sorrel are happy here and will come back year after year.

Planting, feeding and cutting for a steady supply

Plant in spring once the worst of the frost has passed, or in early autumn while the soil is still warm. Space plants so air can move between them; cramped herbs in a window box are a magnet for mildew and grey mould, particularly in a damp spell.

Feeding is where many people go wrong. Leafy herbs such as parsley, chives and basil appreciate a weak liquid feed every fortnight through the growing season — a diluted tomato feed is ideal. Woody herbs need far less; a single feed in late spring is plenty, and too much richness produces soft, flavourless growth that flops.

Water little and often in summer, aiming at the compost rather than the leaves, and check containers daily during a heatwave. Cutting is the other half of the bargain: regular harvesting makes plants bushier and stops them bolting. Pinch out basil above a pair of leaves, snip chives right down to about 5 cm, and take parsley stems from the outside of the plant so the centre keeps growing.

Overwintering and keeping the pickings coming

Come October, move tender pots to a sheltered spot against a house wall, which gives you a degree or two of extra warmth and shelter from driving rain. Raise containers onto pot feet and cut right back on watering — soggy roots kill more herbs in winter than cold ever does. Rosemary, sage, thyme and bay will usually survive outdoors in most of the UK given decent drainage. Basil will not, so either bring it inside or accept it as a seasonal crop and sow fresh in spring.

To keep fresh leaves within reach right through the winter, sow a small pot of parsley indoors in late summer and keep a windowsill chive pot going. A little protection goes a long way: a cloche, a cold frame or even a clear plastic bottle with the base cut off will carry flat-leaf parsley and chervil through the harshest weeks.

Finally, do not overlook preserving. Freeze chopped soft herbs in ice cube trays with a splash of water or oil, dry thyme and oregano in a warm, airy room, and you will have your own supply long after the last leaf has dropped. Start with two or three pots, learn what your space does, and build from there — a productive herb garden in a small urban corner is entirely within reach.