You can buy the most gorgeous plants in the land, but they won’t thrive if you plant them in the wrong stuff.
As the adage goes: “Look after the soil and the plants will look after themselves.”
The same goes for the compost in your pots and window boxes, so learning a little bit about this most unglamorous of subjects is the secret to having the most glamorous of gardens.
But it can be perplexing for beginners. How do we know if our soil is “good”? Do you have to replace the old compost in your pots every year?
If you’re confounded by compost and stumped by soil, follow these tips and you’ll reap the rewards in the year ahead.
Compost for containers
For plants in containers you need potting compost. Anything that describes itself as peat-free multipurpose potting compost will do.
Avoid composts grown with peat, and sadly this includes John Innes mixes, because ransacking vital carbon sink peat bogs to grow our geraniums is environmental idiocy and peat-free composts are just as good.
Urban gardening tips
One of the banes of an urban gardener’s life is having to replace the old compost from their pots, especially when they live several storeys up or have to carry it through a beautifully carpeted sitting room. The great news is that there’s no need to do this.
If you have a tree, shrub or long-lived plant growing in a pot, simply remove the top 5cm of compost each year — now is a good time — and replace this with fresh compost.
Maybe add a few slow-release fertiliser granules such as Miracle-Gro Continuous Release Universal Plant Feed, or organic chicken manure pellets (marshalls-seeds.co.uk, £11.99) while you’re at it.
If you have annuals that have died over winter, the compost in the pots will be compacted and full of old roots, but it’s not irredeemable.
Tip the pot out on to an old compost bag and remove the dead plant and as many roots as you can. Then crumble the compost with your fingers and put it back in the pot.
You’ll probably find the level has dropped considerably. Top up with fresh stuff and a handful of fertiliser pellets and mix together before planting.
When to add garden compost
If you have a garden, your plants will be healthier and more resistant to drought if you add garden compost when you can.
It will not only feed the plants but improve the drainage and soil structure.
This is particularly important in London where the soil tends to be soggy clay with added builders’ rubble.
What is garden compost? Not to be confused with potting compost, which you buy in bags from garden centres, garden compost is old plants, prunings, grass cuttings and kitchen peelings thrown in a heap and left to rot down in the corner of your garden.
It’s full of nutrients and, wonderfully, absolutely free. When the compost has turned brown and crumbly with the consistency of chocolate cake mix, it’s ready to spread on to your soil in a layer around 5cm thick.
What to buy now
Thee ultimate compost bin for small gardens is the Hotbin Mini Composter (suttons.co.uk, £149.99) that you can hide behind a shrub and, thanks to its thermal insulation properties, will produce compost in only 90 days.
Most compost takes about a year to be usable, so if you have space and patience, the Easy Load Wooden Compost Bin (primrose.co.uk, £34.99) is a great budget option.
No room for a bin? But how do you feed your soil if you don’t have a compost bin?
Head to your nearest homestore or garden centre and look for bags of a soil improver such as Miracle-Gro Premium Border Booster or good old farmyard manure — don’t worry, it’s rotted down and won’t have seen a cow for a very long time.
Mulch the surface of the soil with it and let the worms mix it in.