Tricky stuff

Some types of garden waste require caution. One of the undoubted virtues of “hot” composting is that weed seeds and pathogens are killed. But traditional, hot composting is hard to achieve in the average garden, so what do we do with such problematic ingredients? Fungal and bacterial pathogens are the worst, but we do need to keep a sense of perspective.

Pests and diseases that live on leaves and stems don’t enjoy life in the compost pile, so you don’t need to lose much sleep over them. Mildew and black spot are unlikely to survive a long spell

in the average compost pile. On the other hand, most soil pests are quite at home in the pile, and are all too likely to survive and be spread around the garden, as are overwintering diseases. There really is no alternative to keeping material with these problems out of the compost pile.

Not very satisfactory solutions are to burn them or bury them in an unused corner of the garden. It’s better to add them to a habitat pile, a heap of miscellaneous woody waste intended

primarily to provide a wildlife habitat.

When looking at the examples listed opposite, bear in mind that they are for guidance only: no list could possibly be complete, and most available advice on what can be safely composted

is anecdotal and contradictory. Also, the longer a pile is left, the smaller the chance that anything horrible will survive. And last but not least, beneficial microbes in mature garden compost are quite effective at controlling many common diseases. But,

if in doubt, leave it out.

What goes in Material damaged by aphids, black spot, brown rot on fruits, canker, gray mold, leaf miners, leaf mites, mildews, potato blight, sawfly larvae.

What stays out Material that might harbor carrot or cabbage root fly pupae, clubroot of brassicas, eelworms and their eggs, honey fungus, pests that overwinter in soil such as pear midge grubs, root rots of beans and peas, rusts, and viral diseases.