Friday, February 8, 2013

Grasses and the Food Garden

Backyard food gardeners seldom give much thought to grasses, unless they are struggling to keep Bermuda grass from invading a bed, or pulling up crabgrass seedlings. Nevertheless, it is fair to say that human civilization was built on a foundation of grass. In Mesopotamia, the ancestors of wheat were first domesticated. Rice was cultivated in Southeast Asia, and in Central America, the important grass was corn (or its ancestor). In Africa, the grass that provided needed nutrition was sugar cane. Domestication of all these crops, interestingly, occurred almost simultaneously, around 10,000 years ago. Humans have been utilizing grains for much longer, with evidence of flour production going back about 30,000 years.

Although it is theoretically possible to produce other grain crops on a small plot, the grain of most interest to backyard growers is undoubtedly corn. And we generally do not have room to produce anything but sweet corn for corn on the cob in the summer. Growing enough field corn to produce a worthwhile amount of cornmeal would be a challenge without additional space. Growing sugar cane or sorghum presents a similar problem. Except for a sweet corn patch, we won't be growing any grain crops.

While relying on commercial sources for our grain products, we nevertheless cultivate a substantial amount of grass in the form of hedges. When we first bought the house, there were two clumps of Japanese maiden grass (Miscanthus sinensis) standing sentinel at the front entrance. They were removed, divided and replanted elsewhere, mostly along the property lines, and over the intervening decade have increased in number to nearly 100 clumps. These are complemented by several clumps of pampas grass (Cortaderia selloana) here and there on the property. We love their towering plumes in autumn, and in spring before we harvest the plumes, they are much appreciated by nest-building birds as a source of lining material. Neither of these grasses sets viable seed in our climate. Over the course of ten years, we have discovered perhaps 20 Miscanthus seedlings and no Cortaderia. Given the large number of plants and the potential for seed production each plant offers, the number of Miscanthus seedlings is trivial. The plant is unlikely to become a pest, unless of course the climate gets a bit warmer.

In late January or February each year, it is necessary to cut the clumps of maiden grass to a height of about 18 inches. Trimming mimics the effects of dry season wildfires, removing old growth the make way for the new shoots pushing up in spring. In the case of the pampas grass, such pruning sets the plants back and prevents blooming the following season, so we now remove only the plumes. Our signal when the time has arrived to do this is that the plant begins to drop the plumes of its own accord. It is also worth mentioning that the blades of pampas grass have sharp, serrated edges, making it an excellent, nearly impenetrable hedge, but requiring caution and protective clothing when working with the plants.

Pampas grass plumes make excellent tinder for starting a fire. Most of the maiden grass we harvest we save as hay. Hay has multiple uses in a food garden. It provides a clean, weed-free source of mulch, and can easily be chopped into small pieces with a lawn mower to incorporate into the soil or compost. We constructed a holding bin out of pressure-treated deck railing to contain a supply of hay for adding to the composter. (Generally, when you add an inch of kitchen scraps, you should add a couple of inches of loose, dry material to your compost.)

We would encourage anyone with sufficient space to add a row of two maiden grass to the garden. The same plant can provide a privacy screen, a windbreak, a fall display and a supply of hay, depending upon the season. While it thrives on moisture and rich soil, maiden grass is adaptable and, once established, drought tolerant. Numerous cultivars are available, too. We like 'Zebrinus' which grows to about eight feet in height and has lime green stems with yellow markings. Importantly, maiden grass does not produce runners, forming only clumps that increase in diameter with each season's passing. It can therefore be grown in close proximity to crops without concerns about invasiveness.

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