Utilizing Compost and Vermiculture to Build Soil Fertility
Spencer Farm, Malaga, WA
March 30, 2015
For the first farm walk of the 2015 season, Tilth Producers and the WSU Small Farms Team visited Spencer Farm in Malaga, WA (a little south east of Wenatchee). The farm walk focused on this certified organic farms use of compost as their main source of fertility. In addition to the practical knowledge shared by Bruce Spencer, farmer/owner of Spencer Farm, in attendance was David Granatstein from the WSU TFREC who has decades of experience researching organic agriculture and fertility in orchard soils.
Bruce Spencer started the walk by explaining how he has built up his soil fertility over the past 38 years of growing. The site of his 6 acres is extremely rocky and not very tillable. Early on, he purchased top soil from alfalfa fields on the Waterville Plateau. Bruce has always practiced organic methods of production and was one of the first farms to become certified in 1987. In the beginning, Bruce used plenty of approved amendments for his soil. After twenty-years of purchasing inputs for his soil, Bruce calculated that he had spent nearly $250,000. While he recognized the value of healthy, fertile soil he decided that spending that amount of money was not sustainable. So he invested instead in making his own compost on the farm. The two basic ingredients of his compost are wood chips from the county and steer manure from a neighboring farm. Bruce will also add in crop residues and utilizes biodynamic inoculants. Through making their own compost, Spencer Farm eliminated the need for unnecessary amendments and has great soil fertility as a result.
As Bruce took attendees around the farm, he talked about how good soil will smell sweet and alive. He had attendees get a handful of soil and smell and feel it as he spoke about the importance of microbial populations in healthy soil. Besides the addition of four inches of compost to the vegetable areas every other year, Bruce plants a rye cover crop in the fall and turns it under the spring. He’s experimented with different cover crops over the years, but has found rye to be the hardiest choice and one that creates the most biomass. Bruce noted that managing the fertility of annuals versus perennials (as with his fruit trees) could not be more different. With annuals such as vegetable crops, you can learn a lot in one season about soil management whereas with fruit trees, it can take years to understand what is occurring within the soil. Bruce concluded that a person’s best bet is to consult with other fruit growers and current research to guide soil management practices within trees as there isn’t a lot of opportunity to get it right.
A few years ago, Bruce utilized a NRCS-EQIP grant to build a high tunnel for growing fruit trees. This fruit ripens a month to two months earlier than trees out in the field, allowing him some fruit to market earlier. To pollinate these trees, Bruce purchases a bumble bee hive which he sets in the middle of the high tunnel. Honey bees don’t work as well under plastic.
Bruce and Grace utilize vermiculture to clean their potting soil mix, allowing them to reuse it within the season and from year to year. The Red Wigglers will eat the root balls and other organic matter left behind, and adds in their nutrient rich castings. They also vermicompost food scraps from their home and commercial kitchens (where Bruce makes fruit wines). To build his vermicomposters, Bruce utilizes old, plastic fruit bins and he is sure to keep a balance of “greens” and “browns” so that the compost doesn’t get too hot for the worms to do their work.
To build the compost for the rest of the farm, Bruce gets steer manure from a neighbor and wood chips from the city and county. He’ll mix a bit of compost from the last pile to help inoculate it as well as biodynamic preparations from Peaceful Valley. He adds water to the compost if it seems dry and turns it regularly. He recently used chicken compost from an organic source in Canada, but was advised that it’s important to check the resulting compost for salt levels. If the salt levels or EC (electrical conductivity) is too high in compost, it can kill plant roots. Overall, Spencer Farm was a great example of how an organic farm can maintain soil fertility for both annuals and perennials, utilizing compost.
Summary by Angela Anegon.
This Farm Walk is supported in part by WSDA Specialty Crop Block Grant Program and by the Beginning Farmer and Rancher Development Program of the National Institute of Food and Agriculture, USDA, Grant # 2012-49400-19575. For more resources and programs for beginning farmers and ranchers please visit www.Start2Farm.gov.