I have recently been reminded that not everyone who reads this newsletter is a skilled and experienced gardener, and that perhaps a few words about the basics may, occasionally, be welcome. What follows is for those of you who get flustered when NPK ratios are mentioned, and wonder if they’re something to do with a civil war in Turkey. (The experts can toddle off and read about Eco Houses and the £Lewes).

Plants need six macronutrients. The three most important are nitrogen (N), phosphorus (P) and potassium (K, presumably because when the periodic table was put together, P was already taken, so they used its Latin name: kalium). More…