Crossville Chronicle, Crossville, TN

November 12, 2012

PLATEAU GARDENING: Autumn leaves are a gardener’s gold

By C. Rae Hozer
Chronicle contributor

CROSSVILLE — Perform garden sanitation whenever fall weather allows. Summer and autumn months are also good for gathering and saving seeds from desirable landscape plants. Get rid of weed seeds. Leaves are a gardener’s golden opportunity to enrich soil. Do not burn or bag autumn leaves.

A simple way to preserve seeds is to put seed heads in a paper bag until dry. Shake or tap the bag so seeds drop to the bottom. Then pour them into a container with a tight fitting lid. Store seeds under cool (30 to 40 degrees) conditions. Moisture shortens the life of seeds, so keep them dry. One reason weedy plants are unwanted is they spread and out-compete good plants in the landscape. Making many seeds helps them spread. Not eliminating weed seeds now, can lead to garden headaches in the future.

Don’t leave dead plant stalks standing in garden beds, either. Tiny bacterial and fungal spores on infected plant parts spread diseases to plants of the same type next year. (Spores can survive winter cold.) Collect then burn or bag and remove from the area diseased leaves, stems, dried fruit, etc. Insects, slugs and other garden pests take shelter in plant remains and woody trash. Destroy these plant-pest hotels.

In forests leaves fall to the earth, decompose and become humus. Similarly in a prairie or savannah, grasses grow up, then die back laying flat on the ground, then decompose and add organic material to the upper layers of the soil. Organic gardeners mimic these natural processes using plant materials like plant stems and leaves from garden cleanup along with grass clippings and fallen leaves to make compost or mulch. Even those who don’t claim the title ‘organic gardener’ can make compost. Once seeds and diseased plant parts are removed, the remaining waste from fall yard and garden cleanup are the raw materials. Moisture, air, nitrogen and carbon feed the microorganisms that decompose (rot) vegetation, weeds and tree leaves. Decomposition occurs more efficiently when plant parts are chopped up and mixed in the right proportion of carbon for energy and nitrogen for protein manufacturing.

Green materials like grass clippings and kitchen vegetable scraps are nitrogen sources. Fertilizer can be used, too. Dry tree leaves, bark nuggets, wood chips and sawdust are all carbon sources. About 25 parts carbon to 1 part nitrogen is the best carbon to nitrogen ratio (C:N ratio). Using a higher proportion of carbon slows the decomposition process. Too much nitrogen can make a compost pile stinky. Use hand pruners or garden shears to cut plant stems and leaves into pieces before putting them on the compost heap.

Use your lawn mower to mulch and bag fallen leaves. I do that then windrow the chopped leaves in my woods. They decompose by mid-summer the following year. It is a slow but easy method of composting. 

Research indicates some age-old gardening ideas are myths. Adding oak leaves does not make the resulting compost too acidic. Plant materials with a higher acid content like oak leaves and pine needles change to a neutral or slightly acidic pH (approximately 6.5) after decomposition.

Compost from oak leaves makes a good soil amendment or mulch. In his book ‘Weedless Gardening’ Lee Reich, a garden writer who has worked in soil and plant research at Cornell University and for the United States Department of Agriculture says don’t dig (or worse yet, double dig). Instead, top-dress gardens with organic mulches and compost. Reich contends the heavy work of turning garden soil with a shovel or a tiller is not necessary and brings buried weed seeds to the surface where they sprout and grow. Fewer weeds and less work are the benefits you reap from his mulch-don’t-till method.

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Plateau Gardening is written by Master Gardeners for gardeners in Tennessee’s Upper Cumberland Region.  UT Extension Cumberland County at P.O. Box 483, Crossville, TN 38557 (931-484-6743) has answers to horticulture questions, free publications and details on how to become a Master Gardener. Send email comments or yard & garden inquiries to Master Gardener Rae, mgardenerrae@frontiernet.net.