Autumn Leaves Become Compost Thanks to Microbes

Leaves in autumn colors of red, yellow, orange and brown are falling. There was a time that piles were made in yards and on the street for children to play in. Nothing could compare with jumping in them and it was a sad day when they were burned for the season.

Today, leaf piles are still fun for kids to play in but for the most part they are no longer burned. Now we know that burning leaves creates fire danger, smoke and environmental hazards. Also, we have learned that composted leaves are one of the best nutritional tonics for our gardens.

Fall leaves, composted and dug into your garden will improve the soil and keep it productive longer each year. Digging in the compost makes gardening less expensive because less water and fertilizer are needed.

A simple compost bin can be set up in an area that is only 3-feet by 3-feet.

Leaves are high in carbon and low in nitrogen, so add nitrogen. Use fertilizer or organic matter such as grass clippings, manure, garden debris such as weeds, or green waste from the kitchen. Vegetable and fruit peels or scraps, coffee grounds, tea bags and similar non-meat, non-dairy products are best.

To add nitrogen fertilizer, put one-fourth cup of lawn fertilizer between layers of leaves. Or put a layer of weeds and kitchen waste between each layer of leaves.

“Piling the compost pile in layers is easier, but mixing everything with a pitch fork and watering the pile is better,” said Misch Lehrer, manager of Soilutions in Albuquerque NM. Soilutions (www.soilutions.net/) is an organic materials recycler.

Watering is required if you want to be sure to have great compost by spring. If you don’t need the compost for next spring, just let the pile sit for two years until it is ready.

Using the lawn mower to chop leaves can make them so fine that they form a compacted pile that doesn’t have enough air for the bacteria to grow. To open up the pile and add air space, mix in some small sticks and twigs or green matter.

When they are dug into beds, decomposed leaves and organic matter, feed the soil.

Lehrer said, “Compost is created when micro-organisms feed on organic materials and begin the biological process of breaking them down into a form that plants and soil organisms can reuse. Heat in compost is generated by the metabolism of the micro-organisms that are eating the plant material.”

“Technically, compost feeds the microbes. Microbe digestive waste and cadavers feed the plants like fertilizer,” Lehrer said.

You can also use leaves as mulch before they are decomposed. In this form they smother anything that could grow under them. A pile of leaves prevents sun, water and weed seeds from touching the ground. The leaves protect the ground from heat, cold, evaporation and wind.

Leaves left whole or in piles on the yard over winter will smother the grass underneath. Leaves piled onto an area where you want to make a vegetable or flowerbed next year will smother the weeds and encourage the soil below to soften.

Fall planted, spring blooming bulbs benefit from a layer of leaves on top by preventing rain from soaking in and rotting the bulbs.

If composting piles of leaves is not practical, fill trash bags with moistened leaves, close the bag and poke a few air holes in it. In the spring you can dig leaf compost into beds or use it as mulch around plants.