Fall is high season for making compost, the finest of all foods to feed your garden soil. Compost-worthy materials abound this time of year, so all you must do to make a batch is to pile up dead or dying plants, cool-season weeds, fruit and vegetable waste from your kitchen, and maybe some shredded leaves. Will such a simple project really make a difference in the performance of your veggies next year? You bet it will!
With no turning or other fussing, the heap I’m making now will be ready to use early next summer. Rotted but still chunky, the compost will be teeming with microorganisms that suppress dozens of soil-borne diseases. From root rots to more serious bad news like fusarium yellows of tomatoes, compost stifles troublemakers and triggers plants to do a better job of defending themselves.
For a disease-suppressive soil to continue working well, it needs regular additions of compost, so you always need more. In a recent study involving snap beans and corn, soil amended with composted manure reduced bean root rot by 30%, and slashed corn root rot by 67%. But sadly, the disease-suppressive properties of compost didn’t last. After 12 months, the soil needed more bioactive compost.
Compost is also the best way to load up your soil with micronutrients – yet another reason to layer up bean skeletons with beleaguered basil. In an 11-year study on the effect of compost on soil used to grow vegetable crops in Nova Scotia, the composted-amended plots did a far better job of providing essential micronutrients like calcium, magnesium and boron. In the garden, abundant micronutrients play out as far fewer tomatoes with blossom end rot, and broccoli without hollow stems.
The compost you make from your own garden and yard waste is free of unwanted chemicals, too, and this has become a major issue in recent years (see Jeremy’s article on The Trouble with Manure). Sad stories of food gardens in the UK and USA that have been ruined by herbicide residues continue to mount. Until DowAgroscience’s pyralid herbicides (clopyralid and aminopyralid) are removed from the public compost stream, commercial sources of compost and mulch cannot be trusted. Don’t sit back and think the fight is over. This month the suspension of aminopyralid sales was lifted in the UK. More than ever before, when it comes to compost, you need to make your own.
Barbara Pleasant and Deb Martin are authors of The Complete Compost Gardening Guide, which recently won a Silver Award of Achievement from the Garden Writers Association. Their website, dedicated to educational aspects of composting, is CompostGardening.com.