Courtyard gardening is one of the most rewarding ways to grow in a UK home, whether you have a narrow Victorian yard in Bristol, a sheltered suntrap behind a London terrace or a paved nook off a Scottish flat. But pots behave very differently from borders. There is no subsoil to draw on, no worms working through the mix, and no buffer against a hot afternoon or a fortnight of rain. The compost you choose is, quite literally, the whole world your plants live in.

Why Compost Matters More in a Courtyard

In open ground, roots travel until they find what they need. In a 30cm pot on warm paving, they simply cannot. Courtyards are often sheltered and enclosed, which sounds like a blessing but brings its own challenges: reflected heat from walls and stone, poor air movement that encourages damping-off and mildew, and rain shadow from overhanging eaves. A compost that holds moisture too greedily will waterlog roots after a downpour; one that drains too freely will leave plants gasping by mid-afternoon in July.

The ideal is a mix that holds water like a wrung-out sponge while still letting air reach the roots. That balance, more than any fancy ingredient, is what separates compost that lasts a season from compost that collapses by August.

Loam-Based or Peat-Free: The Two Real Routes

Most garden centre bags fall into two broad camps, and both can work beautifully if you understand their quirks.

• Loam-based composts are heavier, containing sterilised soil, peat or a peat substitute, and grit. They hold nutrients and moisture well, resist drying out, and give pots welcome weight so tall plants do not topple. They are excellent for shrubs, bay trees, roses, herbs and anything you plan to keep for more than one season.
• Peat-free multipurpose composts are lighter, cheaper and more sustainable. Modern versions based on bark, coir and green waste have improved enormously, but many dry out faster and can become hydrophobic if left to dry completely. They suit fast-growing annuals, salads and bedding, provided you water attentively and mix in a little extra loam or grit for structure.

If you are buying a single bag for a mixed courtyard, a quality peat-free multipurpose with added loam is a sensible compromise. For permanent pots, spend a little more on a loam-based mix.

Reading Beyond the Label

Bag descriptions can be vague, so look for the details that matter.

• Nutrient content: good composts list an NPK figure and state how long the feed lasts. Three to six weeks is typical; after that, you are feeding the plant yourself.
• Texture: squeeze a handful. It should crumble with a little pressure, not clump like putty or trickle through your fingers like dry sand.
• Grit or perlite: visible pale flecks mean better drainage and aeration, which matters greatly in courtyards where pots sit on hard surfaces.
• Weight: very light bags are convenient for balconies but need more watering and more staking.
• Freshness: compost is a living product. Avoid torn, damp or musty bags, and use them within a season or two.

Blending Your Own Mix

Making your own blend gives you control and often saves money. A reliable courtyard recipe is roughly six parts peat-free multipurpose, two parts loam, one part grit or perlite, and one part composted bark or leafmould. Mix it on a tarpaulin, dampen it slightly, and pot up firmly but not brutally, leaving a 2cm gap below the rim for watering.

For plants that hate sitting wet, such as lavender, rosemary, thyme and most Mediterranean herbs, increase the grit to two parts. For hungry, thirsty plants like tomatoes, courgettes, dahlias and fuchsias, add a handful of slow-release fertiliser and a little extra bark to hold moisture through hot spells.

Feeding, Top-Dressing and Refreshing

Compost nutrients are exhausted long before the compost itself is spent. From around six weeks after potting, start a liquid feed programme: a balanced feed for foliage and flowers, and a high-potash tomato feed once buds appear. Little and often beats a fortnightly drench, especially in rainy spells when nutrients leach away quickly.

Each spring, scrape off the top 5cm of old compost from permanent pots and replace it with fresh, enriched mix. Every two to three years, tip the plant out, trim the rootball slightly, and repot into a mix that is one part new compost to two parts old. This keeps structure and nutrients topped up without the shock of a full change.

Matching Compost to What You Grow

Think about the plant's temperament before you fill the pot.

• Mediterranean herbs and succulents: gritty, free-draining, loam-based mix.
• Salads, herbs and annual bedding: peat-free multipurpose with added grit.
• Small shrubs, bay, olive and citrus: loam-based mix with slow-release feed.
• Roses and climbers in permanent pots: loam-based with extra organic matter and regular feeding.
• Acid lovers such as blueberries and camellias: specialist ericaceous compost, refreshed annually.

Get the compost right and everything else becomes easier. Watering, feeding and even overwintering all work better when roots have air, moisture and nutrients in the right proportions. In a small courtyard, where every pot counts, that foundation is worth a little extra thought at the till.