Testing and amending your soil

Before you buy a single bag of compost, test what you have. A cheap pH kit from any garden centre will tell you in ten minutes whether you are working with acid, neutral or alkaline ground. Most soils in the UK sit between pH 6.0 and 7.5. If you are below 6.0, you can grow rhododendrons, camellias and blueberries easily but will struggle with brassicas and most salads unless you add lime. Above 7.5, and you are on chalk or limestone — lavenders and Mediterranean herbs will thrive, but ericaceous plants will slowly starve.

Structure matters as much as chemistry. Clay soils are fertile but airless when wet, concrete-hard when dry. The solution is not sand — adding sand to clay gives you something close to brick — but organic matter and grit in quantity. Dig in 5–8 cm of compost or well-rotted manure each autumn, plus sharp horticultural grit at one-third by volume if drainage is truly poor. This is hard graft, but it transforms clay within two seasons.

Sandy soils drain so fast that nutrients leach away. The fix is the same — compost — but applied more often and in lighter dressings. A 3 cm mulch every spring keeps organic matter levels stable. If your plants yellow between the veins despite feeding, suspect a trace element deficiency; sandy soils lack the clay particles that hold micronutrients. A seaweed-based feed supplies them quickly.