Tomorrow is World Earthworm Day, so why not improve your whole garden by helping worms?

These tiny, wriggly creatures are fascinating. While running a series of wormery workshops in Borders schools recently, I found that even the more worldly-wise girls were spell-bound, and most of the children didn’t realise the sessions were ‘school work’. Charles Darwin reckoned worms were the world’s most important animals, describing them in an 1881 publication as ‘nature’s ploughs’.

Between them, the 29 species of worms in the UK plough through the ground, breaking down organic materials, thereby producing nutritious wormcast and aerating the soil.

By looking closely, you’ll identify 3 main groups. The reddish epigeic species are surface dwellers and start working on organic matter. The anecic ones, with red or black heads and pale tails draw this material down into the ground. And endogeic worms complete the process by dispersing this goodness as they burrow through the soil. They may be grey, pink, green or blue. If you’re lucky, you might see a 30cm long worm.

Instead of complaining and being annoyed about fallen leaves, compost or use them as mulch to let the worms improve the soil in your garden.

Composting leaves adds fibre-rich carbon to the mix and complements wetter raw fruit and veg scraps and sappy green vegetation. I use the perfect tool to collect leaves from grassy areas: my rotary mower effortlessly sweeps and chops them up. I then cowp the grass box into a special leafmould bay [see my website] and will be rewarded with a precious pile of earth-like leafmould in 18 months.

Leafmould is so valuable that I’ve just finished building a new collection bay to replace its gently decaying predecessor. You can also collect and bag up leaves; avoid the problems many people encounter by leaving the bags open. For drainage, pierce the bag with a fork and place on the soil.

Leaves need a steady supply of winter rain to keep them moist, so a leafmould bay or bag should never be covered. The top layer will be unchanged, but there’s good stuff underneath.

There are so many ways to use leafmould. A sieved mix of compost and leafmould makes wonderfully nutritious potting compost. I also mulch pots and improve soil structure in any poor bed.

Even if the only nutrient my grass gets is a generous contribution from ducks and geese, you could use leafmould instead. To give the lawn a boost, thinly spread fine leafmould over the grass in spring, when growth begins.

Collecting leaves in my large garden is certainly pretty time-consuming, but if you don’t have the dedication of a gardening anorak like me, have pity on your garden and its worms.

Rather than breaking your back by meticulously removing leaves from a herbaceous border, leave them for the worms. You won’t have to buy mulching material if you tuck the leaves between clumps of perennials and emerging bulbs. Over winter, fallen leaves prevent soil compaction and by spring, the worms will have removed most of them and enriched the soil and improved its structure. With higher levels of tannin, beech and oak take a little longer, but could be hand-forked in next spring.

And don’t be tempted to throw out any leaves you’ve swept up or collected in a leaf blower. If you don’t make compost, use them as a mulch round shrubs, hedging, or more generally in a border. My willing recipients include a couple of peonies in a bed next to one path and cordon apples beside another.

All this inspires me to get the next batch of leaves in.

Plant of the week

Physalis peruviana ‘Little Lanterns’. Still cropping well under cover, provides a steady supply of tangy fruits. Pretty and delicious.