Replenishing the nutrients in the soil is key to a good garden. One way to do that is through composting. (Metro Creative Services photo)

Replenishing the nutrients in the soil is key to a good garden. One way to do that is through composting. (Metro Creative Services photo)

Mary Lowther column: Compost a key feature of getting ready for next year

With autumn comes the rituals of winding down the garden to overwinter

By Mary Lowther

The harvest fairs have come and gone. With autumn comes the rituals of winding down the garden to overwinter, removing spent plants to make the compost heap. Next year’s vegetable and fruit crops depend on human intervention for water, weed control and rich soil replete with all the minerals plants need, and compost is a vital part of this cycle. Through fermentation and breakdown of plant and perhaps animal material, compost returns nutrients to the soil for the next crop.

Many commercial growers never use compost apart from digging under spent plant debris and adding manure, preferring to buy chemical fertilizers that don’t add the trace minerals removed with the harvest. They may save on labour costs, but their soils gradually become bereft of these minerals, producing weaker plants until eventually the soil won’t grow anything. We can do better.

Organic growing methods use compost as the linchpin for creating great soil, but if we aren’t replacing trace minerals our soils will also stop supporting plant life and we’ll end up with another Dust Bowl. Food Print magazine writes “Some research has found that synthetic nitrogen fertilizer decreases soil’s microbiological diversity (that is, bacteria, fungi, etc.) or causes soil acidification and a buildup of salts, heavy metal contamination and accumulation of nitrate (which is a source of water pollution and also harmful to humans).”

Gardeners employ various methods for composting. One of my favourites was used by early Australian immigrants who kept their own manure in “dinny buckets” along with plant debris, dug holes in paths and gradually filled them up. Once all the paths were filled, they switched over to grow food in the paths and used garden beds as paths. This replaces trace minerals that leave with the harvest after we have consumed the crop. Author Joe Jenkins composts his family’s “humanure” in a composting heap that he built. His heap exceeds temperature and time required to kill any pathogens and the compost produced fine crops for the 20 years before he published his results.

I don’t compost our manure because of the “yuck factor” certain family members maintain, so I buy trace minerals and add them to the organic fertilizer mix that I spread on the soil at the same time as compost. I’m following two methods this year; the first is a heap near the house for vegetable scraps and the second is trench composting. I chopped up some blackberry vine and kept that beside the wire heap near the house so every time I add vegetable scraps I top it with some of the vines, figuring that the thorns would deter raccoons and such. So far it’s worked. Once this heap is full I’ll move the contents to a trench dug in a garden bed. I also bury the rest of our leftovers in the garden, with a temporary cover of mesh and heavy rocks.

I prefer this slow breakdown of compost because life forms in the heap capture the nitrogen produced and keep it in the compost. Quick, hot compost creators like the barrel method allow much nitrogen to gas off as ammonia so one ends up with less humus. The ideal size of a compost heap is four feet high and four feet wide. Lining the heap with a half inch metal mesh will keep out rats, and a lid also lined with mesh, will keep out rain. We want the compost moist, not wet, as our heavy rains will wash the nutrients away before they reach their target.

Please contact with questions and suggestions since I need all the help I can get.