Week 2 Newsletter

So far, the weather has been great. Temperatures have been balmy and we’ve only had a few days that reached into the upper eighties or lower nineties. While April was an extremely dry month for us (hardly any precipitation) and May moderately dry, June has brought quite a few welcome showers. The dry weather in late May and early June allowed for great field conditions to plow and plant and to bale up most of our straw and first cutting of hay. Finishing the first cutting before the first vegetable delivery greatly reduces the stress on the farm. Most of the hay is sold to a local beef farm, some of it is stored for winter use for our sheep, and the rest is saved to use as mulch in the vegetable fields. We grow hay not only for the animals: it is an integral part of the farm.

The farm is about 300 acres, about 90 of which are devoted to vegetable crop production, 100 to hay, and about 50 to permanent pasture. To maintain fertility on the vegetable land, we import compost and plow under a significant amount of green manure. Green manure is basically a crop that is specifically grown to be plowed under in order to provide fertility to what we call a cash crop (a crop that is exported off the farm). On other farms, sorghum, buckwheat, soybeans, oats, barley, rye, field-peas, red clover, crimson clover, and ladino clover are strictly grown for feed or sold off the farm. At Roxbury Farm you will see those crops cultivated (as well as chickling vetch, hairy vetch, sweet clover, and bell beans) but strictly to help build soil fertility. True, we don’t plow under all of our green manure crops – the rye and hairy vetch are cut and pressed into 900-pound, round bales.

All of our green-manure mixes consist of a member of the grass family combined with a legume. Cereals, such as rye, contain a lot of lignin, which brings stable carbon into the farm, while the legumes, through their symbiotic relationship with rhizobia, help fix nitrogen. Like the green-manure plots, hayfields consist of a mixture of grasses and legumes. That particular mix is nature’s way of being most efficient.

About seven acres of vegetables are planted in non-GMO (Genetically Modified Organisms), corn-based mulch. At first glance, the product looks just like regular plastic, but over time it behaves quite differently. At the end of the season, it breaks down and becomes part of the soil. The dark black surface of the plastic absorbs heat more readily than bare soil, holds the moisture, and helps maintain the organic matter level. Naturally available nitrogen and phosphorus are better available in relatively warm soil. Cold soils do not allow naturally occurring nitrogen and phosphorus to become available to plants, which greatly reduces our ability to produce early crops in the spring. So we fool nature with the use of black
plastic and row covers by increasing the temperature of the soil.

Weeds in between the plastic can be a great problem, as the wheel tracks do not get the proper shade needed to suppress weed pressure. This can be a real dilemma; we space crops such as peppers, eggplant, tomatoes, etc., widely enough to increase air flow and light, but all that light allows weeds to continue to germinate. Once the peppers or tomatoes reach a certain height, we can no longer cultivate the wheel tracks with our tractors. Before you know it, you have a jungle in between the vegetable rows competing with the vegetables for light and nutrients, and creating moist conditions that induce plant diseases.

Conventional growers use an herbicide in between the plastic while organic growers generally despair and seek their cleanest ground for plasti-culture. It is therefore a myth that organic growers use plastic mulch as a form of weed control; yes, it is very effective around the plant, but it creates a huge problem in between the beds. We have experimented with all sorts of solutions, including the seeding down of annual rye grass and Dutch white clover. The thinking is that providing shade by growing another low-growing crop will reduce germination of new weed seeds. This is called living mulch, as opposed to dead mulch like straw, hay, or woodchips.
The suppression works well, except in wet years when the grass and or clover become so vigorous that they become a problem too. Lately, we have switched over completely to the application of dead mulch. At first, we bought in straw bales from a local grower. When that became cost prohibitive (about $1,500 an acre), we started growing our own rye straw. When we don’t make enough rye straw, we alternatively use an early first cutting of hay that is free of weed seeds. The hay mulch has proven to be a great alternative to the use of rye straw.
Last fall, we only had a few bales of rye straw left and Jody wanted to keep some in the barn for bedding for the sheep and pigs. As a result, the garlic was mulched partly with straw and mostly with grass-based hay. This spring, we were pleasantly surprised with the result: the garlic has never looked this healthy. While straw tends to steal nitrogen out of the soil in order to break down, the hay proved to be a source of nitrogen, creating lush growth while suppressing the weeds. The disadvantage is that it takes about twice as many bales to provide the same weed suppression as straw, because the hay tends to break down faster – but, on the other hand, we don’t have to apply any other fertilizer, because the hay feeds the crop.

Hay fields are self-sufficient in their need for nitrogen and carbon. Vegetables take a lot of nitrogen, while they generally exhaust the soil carbon. Removing the hay and applying it as mulch on the vegetables, along with the cultivation of green manures, greatly helps us to reduce our dependence on imported compost and other fertilizer. ~Jean-Paul