Autumn teaches the gardener to honor the need for rest and renewal, in ourselves and in the soil. October is a time to thank the garden for its bounty by cleaning it and returning something to the soil as an offering. These are the final jobs at the end of the gardening year.
Cleaning the garden
When killing frost has finally taken its toll in the vegetable garden, as it will most likely do sometime this month, pull up the plant residue and compost it. Mulches and tender plants like lettuce and spinach can be turned under directly, but the woody stems of tomatoes and vine crops will only tangle in the tiller. Except for the mulches protecting tender perennials, the garden should be free from plant debris. Mice, bugs and disease spores all like to winter over in dead plant material.
Turn organic matter into soil
Fall is the best time to improve the soil by adding organic material. Heavier soils contain a lot of clay, and clay soils take a long time to warm up and dry out in the spring. the structure of the soil can be damaged by cultivating when it is still too wet.
Premature tilling in the spring can compact a heavy garden soil into something resembling a giant brick. In fall, the soil is still moist and workable, but not soggy.
Whether your soil is clay, sand, silt or loam, the best addition you can make to your garden soil is organic matter. This means leaves, compost, manure, grass clippings, sawdust, bark, conifer needles, straw…anything that’s inexpensive, free of toxins and plentiful.
Organic material improves the structure of any soil, increasing the penetration of air, water and nutrients. It makes clay soil less sticky and sandy soil less arid. It supplies micronutrients generally unavailable in commercial fertilizers and improves the soil’s capacity to hold water and nutrients by as much as 30 times. This is complex soil chemistry at its best, and is something you cannot buy in a bag.
In the summertime, grass clippings and weeds provide easy nitrogen for our compost piles. In the fall, when nitrogen is really needed to break down all those crunchy brown leaves, that source dries up. Solution: coffee grounds (and the acid is an added boon to our alkaline soils). Talk to your friendly neighborhood barista and see what you can arrange.
Microorganisms use nitrogen to break down raw materials into the organic element of soil called humus (HUE-muss). This is not to be confused with hummus (HUM-us), the very tasty Middle Eastern dish made with chickpeas.
Essentially, whenever you incorporate organic matter into the soil, you’re composting right in the garden. Don’t use more than 500 pounds of manure per 1,000 square feet annually. Excessive use may result in salt problems or the toxic build-up of copper, zinc, arsenic, and heavy metals in the soil.
An annual application of two to three inches of organic material is sufficient and will steadily improve the solid each year. Turn it in with a spading fork (or a tiller) as deeply as possible. The depth determines how far down into the soil future roots will be able to grow.
Mulching after the ground freezes
With the vegetable garden cleared out and tilled, the last job is to mulch around tender perennial flowers. The purpose of winter mulching is to prevent the alternate freezing and thawing of the ground which heaves roots out of the soil and exposes them to drying—something like freezer burn on frozen food.
The best candidates for winter mulching are young perennials facing their first winter. Their shallow roots are more susceptible to temperature fluctuation near the surface than the older, more deeply established plants.
Wait until the leaves and stems are dead and the ground is frozen hard before applying winter mulch. A mulch applied before hard frost will actually cause more damage than no mulch at all. It prevents ground heat from radiating back to the plant at night and may delay dormancy.
To prevent snow damage
The one thing I do with roses before winter comes is to cut off the heavy candelabras that have formed during the summer, leaving sparsely branched stems that won’t break under the weight of heavy snow.
If snow arrives before the leaves have dropped from fruit and ornamental trees, put on a hat and go out and shake the branches. Snow trapped by leaves gets very heavy and can cause major limbs to break.
A version of this story appeared in CATALYST’s October 1990 edition. But this information is well worth repeating.