Q Can you recommend a soil-testing kit for the home gardener? Roger Jackson, Derby

A Different DIY soil-testing kits are available from garden centres or the internet for a few pounds. They usually include tests for pH and major plant nutrients – nitrogen, phosphorous and potassium. Kits are easy to use and give a reasonably good indication of pH, but always follow the sampling directions given by the test.

All work on the same principle of adding an indicator to a mix of soil and distilled water and comparing the colour reaction with a chart. Two Wests & Elliott Ltd (www.twowests. co.uk; tel: 01246 451077) offer a mini soil-testing kit for £18.75. It’s claimed it will do up to 50 tests.

Testing can be done at any time but spring is best. Importantly, wait three months if you have added lime, fertilisers or organic matter.

Alternatively, the RHS can provide a professional laboratory base analysis, which also details the steps necessary to address any soil deficiencies. It costs £30 (£25 members) (tel: 01483 479700; www.rhs.org.uk).