Start With the Soil, Not the Plants

Spring in a small garden is a game of inches. Every pot, every square metre of border and every windowsill needs to work harder than in a larger plot, which means the growing medium underneath everything deserves your attention before the first seed packet is opened. After a wet British winter, compost in containers is often exhausted, waterlogged and slumped below the rim, while border soil may be compacted from months of rain and footfall.

Wait until the soil is workable. Squeeze a handful: if it clumps into a sticky ball or glistens, hold off for a week and let it drain. Working wet ground smears the structure and sets you back a season. Once it crumbles, you can get going.

In beds, fork over the top 10–15cm lightly, removing weed roots as you go, then spread a 5cm layer of garden compost or well-rotted manure as a mulch. Don't dig it in — the worms will do that for you, and you'll avoid disturbing dormant perennials that are just starting to push through.

Refresh Compost in Pots and Containers

Container compost has a hard life. It dries out, gets leached by rain and loses its structure in a single season. If you can, tip out the top 5cm of old compost from each pot and replace it with fresh, peat-free multipurpose compost, mixed with a handful of slow-release fertiliser and a little horticultural grit for drainage.

For long-term plantings such as shrubs, small trees, agapanthus or rosemary, aim to replace roughly a third of the total volume where root space allows, teasing old roots out gently first. If a plant has filled its pot completely and the roots are circling, it's a repotting job rather than a refresh.

A few rules that save time and money:

• Never reuse compost from a pot that held a diseased plant — bin it, don't spread it.
• Terracotta dries out fastest; glazed pots hold moisture much better in a small, sun-trap garden.
• Check drainage holes before filling. Blocked holes kill more container plants than cold ever does.
• Top-dress with a thin layer of grit to deter slugs and keep the surface from splashing.

Prune Out Winter Damage

Now is the moment to be honest with a pair of secateurs. Cut back any stems killed by frost, snapped by wind or blackened by wet cold, working down to the first healthy green bud or clean, cream-coloured wood. If you're unsure whether a stem is alive, scrape a little bark with your thumbnail: green underneath means keep, brown and dry means cut.

Hydrangeas can have their old flower heads trimmed back to the first fat pair of buds; on mopheads, leave the framework intact. Penstemons, salvias and fuchsias benefit from having last year's growth shortened to a low, tidy shape, removing any soft tips that won't survive another cold snap. Bush and shrub roses should have dead, crossing and spindly stems removed now, leaving a clean open centre that lets air move through — vital in a cramped garden where disease spreads quickly.

Don't compost suspect material. Burn it, or put it in the council green waste bin, rather than risk spreading problems around a small space.

Sow Hardy Annuals for Early Colour and Cover

Hardy annuals are the small garden's best value. They germinate in cool conditions, tolerate a late frost, flower within ten to twelve weeks and can be grown in gaps, at the front of borders, in window boxes and between slower perennials that are still asleep.

From March to mid-April, direct sow into a prepared, raked tilth where plants are to flower — they resent root disturbance, so sowing in place suits them. Keep rows or patches small, roughly 20–30cm apart, and thin seedlings to 15–20cm once they're large enough to handle. If slugs are a problem in your patch, start them in modules or root trainers under cover and plant out after hardening off for a week.

Reliable choices that cope with British spring weather include:

• Calendula — quick, cheerful and edible petals for salads.
• Cornflower and nigella — excellent for cutting and for filling bare gaps.
• Larkspur and sweet pea — tall options for a wall or obelisk, where vertical space is free.
• California poppy and poached egg plant — low, self-seeding and happy in poor, dry soil.

Support Early, Plant in Layers

Put supports in before plants need them. Pushing a cane into the ground beside a mature dahlia is far harder than placing it while the soil is loose and the stems are short. Pea sticks, hazel or birch twig panels and simple metal grids all but disappear once foliage grows through them, and they cost nothing in visual space.

In a small garden, layering is a design strategy as much as a planting one. Underplant shrubs with spring bulbs and hardy annuals, grow climbing beans or sweet peas up a wall while salad crops occupy the ground below, and use the vertical plane: fences, railings, trellis and hanging baskets. Use dwarf or patio varieties of tomatoes, courgettes and runner beans where a full-sized plant would swallow the border.

Protect, Feed and Hold Back on the Hose

Keep a roll of horticultural fleece to hand until late May. A single cold night can undo weeks of growth, and a double layer of fleece or an upturned cloche will protect tender new shoots without any real effort. Move pots of tender plants back under cover if a frost is forecast.

Begin feeding only when active growth is clearly underway — usually late March for containers, April for most borders. A balanced liquid feed every fortnight suits pots; borders with a mulch layer rarely need more than one granular feed in spring.

Finally, resist the urge to water daily. Spring rain usually provides enough, and roots grow deeper and stronger when they're made to search. Water thoroughly when you do, until it runs from the drainage holes, then leave the pot alone until the surface is dry a couple of centimetres down. That single habit will do more for your plants through summer than any other job you do this month.