Growing vegetables in a coastal allotment

Why a coastal plot is its own kind of growing

An allotment within sight or smell of the sea is a gift and a challenge in equal measure. You will very rarely see the hard, ground-freezing frosts that stop play ten miles inland, and the light on a clear evening in late August can be extraordinary. Salad leaves keep going into November, and purple sprouting broccoli overwinters happily where inland growers lose theirs. But you are also gardening in moving, salty air, and that changes almost everything about how you plan a plot.

Salt spray is the thing newcomers underestimate. On a windy day, invisible droplets of seawater travel surprisingly far inland — a good gale will carry them a mile or more — and they settle on leaves, burning the edges, scorching new growth and setting plants back by weeks. Wind alone does its own damage: it dries soil faster than sun ever will, snaps stems, shreds soft leaves and causes what growers call wind scorch, where foliage goes brown and papery on the exposed side. Sort out shelter and soil, and the rest of the job is ordinary vegetable gardening. Ignore them, and you will spend the summer wondering why everything looks sulky.

Coastal soil tends to be thin, sandy or gravelly, free-draining and often low in organic matter. That is not a disaster. It warms up early in spring, it is easy to work, and it drains beautifully in a wet winter.

Pick varieties with some grit about them

Choose tough, wind-tolerant crops and you will halve your workload. Anything that evolved on a cliff or a shingle beach will shrug off what a coastal plot throws at it.

• Kale — 'Redbor' and 'Nero di Toscana' stand up to wind, keep cropping through winter and taste better after a frost.
• Chard and perpetual spinach — 'Bright Lights' looks superb and keeps producing for months. Both cope with salt far better than true spinach.
• Beetroot — 'Boltardy' or 'Detroit Globe' sown in early May will give you roots by August.
• Carrots — 'Early Nantes' or 'Flyaway' for a short, fast crop in light coastal soil. Sow thinly and keep them watered.
• Broad beans and peas — 'Aquadulce Claudia' sown in October or November overwinters well in a mild maritime climate.
• Potatoes — 'Kestrel' and 'Sarpo Mira' have good blight resistance, which matters in damp sea air.
• Leeks and onions — 'Musselburgh' leeks and 'Sturon' onion sets are reliable and unfussy.

Avoid tall, top-heavy crops on the most exposed beds. Sweetcorn, climbing French beans and cordon tomatoes will need serious shelter or a polytunnel. Save the windiest corner for a fruit cage, a compost heap and a shed.

Feed the soil and lift it up

Coastal soil is usually hungry, so organic matter is your single best investment. Add two generous buckets of well-rotted manure or garden compost per square metre every autumn, spread on the surface and let the worms pull it down. Do not dig it in deeply — you will only break up the structure and encourage the wind to dry it out.

Raised beds are worth the effort here, and not just for looks. Twenty to twenty-five centimetres of depth gives roots a reservoir of moisture that holds through a drying easterly, improves drainage in a wet winter, and warms up a fortnight earlier in spring. Fill them with a mix of topsoil, compost and a little sharp sand if your ground is heavy.

Mulch everything — straw, grass clippings, leafmould, compost — after planting. It keeps moisture in and stops the wind stripping the top few centimetres of soil dry. Rinse seaweed well before adding it to the heap if you are collecting from the beach, and only ever take seaweed that is already loose on the sand, never torn from the rocks.

Build shelter without building a wall

A solid fence or dense hedge is the wrong answer. Wind hits it, rises, and crashes down on the other side with more force than before. What you want is a permeable barrier that filters the wind and slows it down.

• Green windbreak netting at about 40 to 50 per cent porosity is ideal. Fix it to posts so the top sits roughly level with the tallest crop you plan to grow.
• Plant a low hedge of rosemary, lavender or sea buckthorn along the most exposed boundary, if your site allows it.
• Use temporary hurdles — woven willow, pallet collars wrapped in mesh, a row of sturdy old raspberry canes — around tender seedlings.
• Leave a gap at ground level. Air must move through, or you create a still, damp pocket where mildew thrives.

Even a 60-centimetre barrier around a seedbed makes a noticeable difference to germination and early growth.

Protect young plants from salt and wind

Seedlings are the most vulnerable stage, and a single salty gale can wipe out a fortnight's work. Harden everything off properly, then plant out on a still, overcast day and water well.

Fleece, cloches and homemade cold frames made from old windows are your best friends from March to June. After a storm, walk the plot with a watering can of fresh water and rinse the leaves of anything that looks scorched — a quick wash removes the salt before it does permanent harm. Plant slightly deeper than usual, earth up potatoes and brassicas, and stake anything taller than your knee.

Make the most of a mild, sea-washed climate

Once you have shelter and soil sorted, coastal growing starts to feel like cheating. Frost is rare, so you can sow overwintering broad beans, garlic and Japanese onions in autumn and harvest through the lean months. Autumn-sown salads often crop right through winter under a cloche.

Sea fog and fret do cut light levels, so keep crops well spaced and avoid overcrowding. Water in the morning rather than the evening to reduce slug damage, and fit a water butt to every downpipe you own — wind dries soil fast, and you will use more water than you expect. Do those things, and a plot by the sea will reward you with some of the earliest, sweetest and most hard-won vegetables you have ever grown.