CHOOSING YOUR COMPOST
Some plants need specific types of potting compost to ensure they grow well in containers. Opinions tend to vary on the exact mixes, but here are my preferences
Annuals and vegetables will do well in peat-free multi-purpose compost, as long as you also give them a liquid feed every week, from a month after planting right the way through summer. The same compost is suitable for hanging baskets and temporary residents in containers that are not going to remain there for more than half the year.
Alpine plants need gritty compost that can provided fast drainage, so add sharp grit and sieved compost into clean topsoil, as well as a light dusting of blood, fish and bonemeal.
Lime haters, such as rhododendrons, azaleas, camellias and blueberries, require ericaceous (lime-free) compost.
Trees and shrubs need a weightier mix in their containers that will provide greater stability and also hold on to nutrients for longer. Multi-purpose compost with added
clean topsoil and an extra dusting of fertiliser will do the trick, or you could use a peat-free, multi-purpose compost that has added John Innes. This is one way to go peat free, while still using a compost that has a rich mix of ingredients such as loam.
Permanent residents in pots and tubs should have the top few inches of compost scraped away each spring and replaced with fresh. You can add a sprinkling of slow-release fertiliser granules too, to give them a boost. I prefer to stick to blood, fish and bonemeal, worked into the surface and carried down to the roots by subsequent waterings. It’s organic and really does the trick. You should try to repot long-term plants every three or four years, knocking them out, chopping away some of the outer roots and compost, then replacing it with fresh. They’ll remain far healthier and last far longer as a result, even though it might be a bit of an operation.