Mulch or Cover-crop for Fall
Nighttime chill, holding the threat of frost, triggers changes in our gardens (and in us), prompting the close of the growing year. Experienced gardeners know that preparation for the next gardening year starts well in advance of its arrival. In dry spells, such as the one we have recently experienced, the more moisture-retentive organic matter in the soil, the better the survival and growth for the coming year.
In vegetable gardens, as crops are harvested and cleared, various “green manures” or cover crops may be sown. This is a term describing plants specifically grown to be tilled into the soil, instead of yielding harvestable crops. After protecting the soil surface they are incorporated into the soil; the breakdown of their root systems and green top growth supply the soil organisms with valuable nutrition.
Depending on the season, this might be a warm weather cover crop such as buckwheat, grasses, or legumes. Oats are used later on; they will winterkill but still hold the soil. Winter rye is one of the most commonly used cold weather cover crops; on the Vineyard it usually holds over the winter and resumes growth in spring. Blends are also available, either locally or through seed catalogues, containing mixtures of both legumes and other types of plants.
The aim is that, apart from cool weather crops still in place, the garden is completely covered, either with green, or animal, manure or mulched with organic matter from compost or leaf piles. An over-wintering crop, such as garlic or fall-planted potatoes, also benefits from being mulched.
Cover cropping is usually restricted to vegetable patches and agricultural soils, while mulching is what happens in the ornamental garden or shrub border. The goals are the same, however: to cover the soil surface and protect it from wind and water erosion; and to layer on organic matter that feeds and enhances soil organisms, whose action adds humus.
There is a style of mulching that resembles the application of a “mulch blanket,” which stays there, all season long, for the purpose of suppressing weeds and minimizing maintenance. This differs from the application of mulch that is worked and cultivated, so that it is continuously incorporated and digested by soil organisms.
Gardeners may hear about intricate rotational systems for vegetable gardens, and the green manures specific to the rotation. This is good husbandry but is confusing. Until one has gardened in a specific spot for a number of years and gotten to know it, much of this is guesswork, soil testing notwithstanding. If you adhere to the guideline of getting as much organic matter into the soil as you can, you will be improving it.
Take soil samples for testing now. Go to the UMass soil testing website for information,soiltest.umass.edu. Other soil testing labs that perform more intensive types of testing do exist; they may be found with an internet search. Be prepared to take the advice that is sent to you with the results, as part of your fall garden work.
Food Garden: Harvesting & Storing
Harvest seeds and herbs for drying, such as dill seed, peppermint, and sage, for use as teas, seasoning, and for seed to sow in the coming year. I cut sprigs and seed heads, tie them in bunches with garden twine, and place them in paper bags to dry. The bags catch whatever shatters, or breaks off. Harvest dry shell beans and finish drying on trays, to be shelled and stored when they rattle in the pod.
Plant garlic in prepared, fertile soil by separating the cloves and planting up to four inches deep and 6-8” apart in rows at least one foot apart. Sow hardy crops that will be grown under reemay or other forms of cover over the course of the winter. Dig and divide rhubarb roots: replant in soil that has been amended with good compost or well-rotted manure. Cut down asparagus tops when yellow and mulch the crowns with compost or well-rotted manure. (Rockweed — not eelgrass — and algae are dynamite if you can harvest some!)
Harvest squash and pumpkins; cure before storing. After frost has blackened tops, dig and cure dahlia roots; label well before storing. Harvest fruit that stores, such as apples and pears; only perfect ones may be stored; process the rest. Fall-bearing raspberries are bountiful; I pick and freeze about a pint each morning before work, by traying them in a single layer in the freezer, and then pouring into zip lock bags. Pull cabbages and store, roots and all, in cellars or other cool, darkened place. Four good-size cabbage heads yield about seven quarts of naturally fermented sauerkraut, which may be stored indefinitely in the fridge.
Cut-downs proceed as perennial plants finish their business. With the dry conditions, cutting down sooner than usual may be helpful to drought-stressed perennial plants. Re-work edges, weed, and cultivate, prior to top dressing with low number organic soil food and capping with mulch.
Here is a timesaving move: certain beds may be dealt with by using a power mower on them, blade set high. It speeds things up considerably. Rake up the resulting debris and compost it, top-dress with fertilizer, and then cover bed with mulch or compost. With cleaned up edges the entire bed looks tidy and well ordered for the coming season.
Peonies and iris, both bearded and Siberian, may be dug, divided, and reset, using compost or leaf mold to enhance the planting hole. (Refrain from fertilizing directly in planting holes.) Likewise, strong growers such as lysimachia, Shasta daisies, phlox, some hostas, and many asters may be cut down, dug, and separated into smaller pieces for replanting. The same goes for an ornamental grass that has become out-of scale for its location. Cut it down, dig the clump, and then divide it using the classic, “two spading forks back to back” to prize the root mass into smaller chunks.
Evergreens, especially the broad-leaved ones, such as rhododendron, pieris, skimmia, and sarcococca, continue to transpire all winter, and lose valuable moisture from their tissues during our up-and-down, freeze/thaw cycles. Newly planted trees and shrubs are at greater risk too. The unusual dryness of this fall is placing additional stress on these plants, since going into winter in a desiccated state is a real killer. Provide supplemental water and spray these plants with an anti-desiccant to help them hold onto critical moisture levels.