One of the blessings most North American gardeners enjoy is the cyclical nature of the pastime. While I have written about the joy of season extension and greenhouse production, having a season of rest makes the garden that much more appealing as spring approaches. You may be interested in knowing that an off season is very beneficial to the garden as well.
The benefits of a season of rest vary somewhat depending on what climate we are blessed to live in. But in every area of the country, it is simply good management to clean up the garden at the end of the season. Some insect pests would enjoy over-wintering in the residue of the crops they feed upon. Getting rid of weeds among perennial berries and other no-till areas will make spring much more enjoyable. And I can tell you from experience that pulling up mulch plastic next spring is NOT going to be easier than now.
Growers in the North country have two very separate benefits that come with winter. Some get one or the other, and some get both in most winters. The two benefits are frozen ground and snow cover. Frozen ground helps to alleviate compaction. As ground freezes, it swells. When it thaws, loose, open space is left. Snow cover is also very beneficial but from a different angle. Under the cover of snow, microbial life can flourish all winter long. In soils with a healthy microbial life, a winter of heavy snow cover can leave soils just as loose and porous as if they were exposed to freezing and thawing.
Growers in the South do not have the benefits of winter. Even there, though, a period of rest and slow plant growth helps to revitalize the soil. Only in tropical and subtropical areas where the counter cycle is drought rather than cold, does rest cease to be beneficial.
Outside of freezing action on soil structure, the benefits of the season of rest are all more or less related to microbial function on plant nutrients. Many nutrients in the soil reserves only become available to plants as microbes digest them. Phosphorus and calcium tend to bind to each other and be unavailable to plants. The metal elements found in soils such as copper, zinc, manganese, and molybdenum are often found only in oxidized or rusted state. As such they are totally unusable by plants. Microbes, primarily bacteria, will consume these materials to support their own life cycles, and, as they reproduce and die, the nutrients become available plant food.
The bacterial waste food for plants is also a food for fungi and many other soil-dwelling creatures both visible and invisible to the unaided eye. Many of these other soil dwellers are in direct competition with plant roots for the nutrients needed for growth and reproduction. Many of these nonbacterial soil organisms are very beneficial in long-term soil building. Particularly fungi are directly responsible for the production of humus and stable humic substances that are essential for building soil.
We can help this process all summer long by using foliar nutrition and other good gardening practices to keep our crops as healthy as possible. A healthy crop will exude more sugars and feed more bacteria than an unhealthy, struggling crop. More sugars and other root exudates equals more bacteria which equals more available nutrition. Hopefully this will result in enough for all the plant needs as well as the additional feeders.
But what happens when we remove plants from the equation? Ah, now we’re getting to the benefits of the off season. When soil microbes are not supporting the demands of growing plants, they have more ability to feed each other, making significant beneficial changes in the soil. With decreased plant growth there is a decreased supply of sugars. But even so, there is much more nutrition available for soil microbes when they do not have to compete with growing plants. Under the right conditions the results can be astounding. Many times I have seen amazing changes in soil structure from fall to spring when we take action in the fall to help speed up this process.
As the season winds down, what can you do to ensure that you will receive maximum benefit from your garden’s downtime? The most important thing, whenever possible, is to establish a cover crop. Not having significant nutrient competition from a growing crop is the major plus of winter, but that’s not to say that the soil should be devoid of plants. Having living plant roots in the soil all year long is greatly preferred. For many plants, root growth continues all winter long even when the tops are basically dormant. Having growing roots helps to feed and maximize diversity of many different soil dwellers.
Also many soil amendments are best added at this point. Do you need lime or additional phosphorus? If you do, the ideal time to apply it is between a killing frost and snow cover. This same window is also the best time to apply manure or unfinished compost. There are beneficial microbial inoculants that you can apply with good results in the fall. One rule for applying microbes is to always apply with a food source. A mixture of molasses and liquid fish works well. This is not meant as an exact formula, but, generally speaking, an ounce of microbial stimulation in the fall is worth a pound in the spring. There are various companies that recognize this point and have products designed specifically for fall. These vary somewhat but typically contain combinations of sugars and minerals to stimulate microbial activity.
Treat all your little creatures right this fall, and, while you are sitting beside the fire with a cup of hot chocolate and stack of seed catalogs, they will be busily building the garden of your dreams!