Our short growing season in Scotland makes it hard to get more than one crop a year in a bed. So as we start clearing away the summer veg, how do we fill any vacant space?

You can always sow a few quick-growing white turnips, radish, beetroot or salad leaves, but they don’t take up much of the ground that will need filling.

The golden rule is to never leave a piece of ground bare. Unwelcome weeds will quickly colonise it and winter rains will compact the soil and some nutrients will be leached away. So some kind of winter duvet is essential.

There are several options: free or very cheap material, one of the expensive online enticements, or a living mulch. And we have to remember that this has been the Year of the Slug. And, judging by all the anguished references to molluscs in the media at the moment, I’m not the only one suffering.

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So we should bear slugs as well as cost in mind when deciding on a mulch. Undoubtedly cardboard is the cheapest choice. After removing any perennials like docks and dandelions, simply cover the ground with a sheet of cardboard, minus plastic tape and labels. It’s none too sightly, but you should still have time to spread freshly mown grass on top of the cardboard.

If you have enough half-rotted compost, you could use that instead, with the added bonus that the cardboard will prevent any seed in the compost from rooting into the soil. By next spring, the card and its covering will have mostly rotted down. There’s just one problem: slugs love cardboard, it provides shelter and makes a decent meal, together with a grass salad.

And that’s the trouble. Most biodegradable mulches provide shelter for our garden pests.

Straw is another free or cheap possibility for some people. It does work well and is a little less mollusc-friendly. Specially treated Strulch is better, adds nutrients as it rots down, but is frankly very expensive if you have a largish area to cover. Sheep wool is ideal, especially as it does seem to deter molluscs. But it, crazily, is very pricey and is way beyond most of our pockets.

Living mulches, or green manures, are coming back in fashion. The best overwintering species are Hungarian or Italian grazing rye, vetch and red clover. The rye, when cut down and dug in, is straw-like and adds valuable structure especially in thin soil. Vetch and clover fix nitrogen, which is released into the ground.

Sow these green manures in the open ground no later than mid September. The plants provide cover, retain soil nutrients and prevent leaching. Approximately a month before using ground in the spring, strim down, allow to wilt and dig in.

(Image: unknown)

Plant of the week

Clematis ‘Allanah’ flowers from August until autumn weather spoils the show. The rich, velvety red flowers are large and have a brighter red stripe down the centre of each petal.

As with all clematis ‘Allanah’ needs rich, moist but free draining soil and to have its roots shaded by mulch or other vegetation. It needs hard pruning, cut to 30-40cm above ground level, in February/March as the flowers are produced on the current year’s growth.