Growing Salad Leaves in Small Spaces

Small Space, Big Rewards

You do not need a vegetable patch to pick your own salad. A pair of window boxes, a single trough on a sunny step, or even a few deep pots on a balcony will give you handfuls of fresh, tender leaves from spring right through to the first frosts. Salad leaves are quick, forgiving and genuinely happy in containers — in many ways they do better there than in open ground, because you can control the compost, the watering and the pests.

The secret is to grow the right kinds of leaf — the ones that regrow after cutting — and to sow little and often rather than in one great flush. Do that, and you will rarely buy a bag of supermarket salad again.

Choosing Containers That Work

Depth matters. Lettuce, rocket and spinach all have relatively shallow roots, but shallow compost dries out fast on a sunny windowsill. Aim for at least 15cm of compost, and 20cm if you can manage it. A standard trough 60cm long and 20cm deep will happily hold a row of lettuce or a thick ribbon of rocket.

• Drainage: check for holes before filling. Standing water rots roots faster than anything else.
• Colour: dark containers absorb heat and warm the compost earlier in spring — useful in March, less welcome in July.
• Weight: a full trough is heavy. On a balcony or windowsill, use a saucer underneath and think twice before filling a large pot with heavy soil-based compost.
• Material: terracotta dries out quickly; glazed pots and plastic troughs hold moisture far better.

Use a peat-free multipurpose compost, and mix in a couple of handfuls of garden compost or well-rotted manure if you have it. Salad leaves are hungry, fast-growing plants.

The Best Leaves for Cut-and-Come-Again

Not every salad crop regrows neatly. Hearting lettuces are one-cut wonders; loose-leaf types keep producing. Look for these on the seed packet or plant label.

• Loose-leaf lettuce: 'Salad Bowl', 'Lollo Rossa', 'Green Oakleaf' and 'Red Salad Bowl' are classic cut-and-come-again varieties.
• Rocket: wild rocket is punchy and hardy; salad rocket is milder and faster. Both crop repeatedly.
• Spinach: 'Perpetual' (also sold as spinach beet) is the most reliable in containers, cropping for months. True spinach 'Medania' is tender but bolts quickly in heat.
• Extras: mizuna, pak choi, corn salad, chard and mustard greens all work on the same principle.

A mixed sowing gives you the best of everything: sweet, peppery and earthy all in one cut.

Sowing Little and Often

The single most useful habit is succession sowing. Rather than filling the whole trough in April and having more leaves than you can eat for three weeks, sow a short row every two to three weeks from March to August. That way something is always at the perfect stage.

Sow thinly — roughly 1cm deep and a couple of centimetres apart — and cover with a fine layer of compost. Water gently with a rose attachment so you do not wash the seed about. Most salad leaves germinate in seven to ten days at around 15-18C, which is roughly a cool windowsill or an unheated greenhouse.

If the seedlings come up thickly, thin them to about 5cm apart for lettuce and spinach, closer for rocket. The thinnings are edible — treat them as your first harvest.

Water, Feed and Keep Them Cool

Consistency is everything. Dry spells followed by soakings encourage bolting, bitterness and split leaves. Check containers daily in summer; they may need water twice a day during a hot spell.

• Water: in the morning, at the base, so leaves are dry by nightfall. This reduces mildew and slug damage.
• Feed: a weak liquid feed every fortnight keeps leaves sweet. Too much nitrogen makes soft, sappy growth that pests love.
• Shade: in July and August, move troughs into light shade at midday. Lettuce and spinach bolt in heat.
• Pests: slugs and snails are the main enemy. Check under the rim after rain, and use copper tape or beer traps on a small scale.

If a plant does run to seed, cut the flower stem off at the base — sometimes it will produce a few more leaves, and the flowers themselves are edible and pretty.

Harvesting Without Stopping Growth

Cut with scissors about 2-3cm above the compost, taking the outer leaves first, or take the whole row at once for a bigger haul. Never cut into the growing crown in the centre of the plant, or it will not regrow.

After cutting, water well and give a weak feed. Most loose-leaf lettuce will give you three or four cuts; rocket two or three. If a plant starts to look tired and woody, pull it out and sow the gap afresh — you will have new leaves within a month.

In mild areas, winter varieties such as corn salad and winter purslane will keep you picking right through to March. Cover with a cloche or fleece when hard frosts are forecast, and you can stretch the season well beyond the autumn.

There is something quietly satisfying about stepping outside with a bowl and a pair of scissors, and coming back with a salad that was growing ten minutes earlier.