Sandy soil is the mixed blessing of the coastal garden. It drains within minutes of a downpour, warms up early in spring and is a pleasure to dig whatever the weather. It also holds on to almost nothing, so the compost, feed and water you lavish on it can vanish by the following season. The encouraging news is that sandy ground responds beautifully to steady improvement, and you can grow a superb range of plants on it while the soil is still maturing.

Understanding what you are working with

Sandy soils are made of relatively large mineral particles with plenty of air space between them. Water runs straight through, taking dissolved nutrients with it, which is why plants on light coastal ground so often look pale, stunted or quick to bolt. The same openness means the soil dries and warms fast, and it can be worked far earlier in the year than heavy clay.

Two coastal quirks are worth knowing. First, soil near the sea is often thin, sitting over shingle, chalk or rock, so you may be gardening in little more than a foot of workable ground. Second, salt-laden winds scorch foliage and add to the stress that free drainage already puts on plants. Many seaside soils are also on the acidic side, especially where heathland or pinewoods sit inland. A simple pH test kit from a garden centre will tell you whether you need lime for brassicas and clematis, or ericaceous compost for camellias, hebes and pieris.

Adding organic matter: little and often beats one big fix

Organic matter is the single best investment you can make. It acts like a sponge, holding water and nutrients in the root zone and releasing them slowly. On sand it also breaks down quickly, because the soil is warm and full of oxygen, so plan on topping it up every year rather than treating it as a one-off job.

• Well-rotted manure or garden compost, spread 5–8cm thick and forked into the top 20cm, is ideal for new beds.
• Leafmould is excellent for lightening the soil further and is free if you have space for a leaf bin.
• Spent mushroom compost is useful but alkaline, so avoid it around acid-lovers.
• Seaweed gathered from the strandline is a traditional seaside resource, but rinse off the salt first and never take it from protected sites.

Autumn is the best time to dig in organic matter, giving worms and weather the winter to work it through. If your bed is already planted, simply lay the material on the surface and let the soil life do the mixing.

Mulch is the coastal gardener's best habit

A permanent mulch does three jobs at once: it slows evaporation, smothers weeds and feeds the soil as it decays. On sand, a layer of 5–8cm of composted bark, leafmould or garden compost will transform how long moisture lingers after watering. Keep it clear of stems and crowns to avoid rot, and top it up each spring.

One warning for exposed gardens: light, fluffy mulches blow away in a coastal gale. Use a chunky bark, or scatter a thin layer of gravel or grit over the top to weight it down. Gravel alone also suits Mediterranean plantings and reflects light back up into the foliage.

Watering and feeding on free-draining ground

Little and often is the wrong approach here. Shallow sprinklings encourage shallow roots, which then suffer the moment the weather turns dry. Water thoroughly and less frequently, aiming to soak the root zone so plants are pushed to root deeper. Early morning is best, and a drip line or soaker hose under the mulch saves both water and effort.

Because nutrients leach away, feed in small doses through the growing season rather than one heavy application. A slow-release general fertiliser in spring, topped up with a liquid seaweed or tomato feed every fortnight in summer, suits most flowering plants and vegetables. Resist the temptation to overfeed: soft, sappy growth is exactly what salt winds and coastal sun damage most.

Plants that relish sandy, salty conditions

Rather than fighting the soil, stock the garden with plants that have evolved for it. Grey, silver and woolly leaves, waxy surfaces and deep taproots are all clues that a plant will cope.

• Shrubs: lavender, rosemary, cistus, santolina, tamarisk, escallonia and elaeagnus.
• Perennials: sea thrift, sea holly, sea kale, sedum, crocosmia, verbena and euphorbia.
• Grasses: stipa, blue fescue and pheasant's tail grass, which move beautifully in sea breezes.
• Shelter: a permeable hedge of griselinia, olearia or hornbeam filters wind far better than a solid fence, which simply creates damaging turbulence behind it.

Plant in autumn while the soil is still warm, water through the first two summers, and give everything a generous mulch. Within a few seasons you will have a bed that looks settled, smells of the coast and needs far less of you than it did on day one.