Cover Cropping on a Diversified Organic Vegetable Farm
(plus soil blocking hands-on!)
Let Us Farm, Oakville, WA
June 1, 2015
It was a rainy day near Oakville as 26 farmers and farm interns gathered at Let Us Farm to learn about cover cropping in an organic vegetable cropping system and engage in a hands-on soil blocking opportunity. Farmer-owners Steve Hallstrom and Cecelia Boulais have been farming for over 20 years and were eager to share how they manage their 88-acre farm. Soil scientist Doug Collins of the WSU Small Farms Program also presented about the use of cover crops for fertility with his graduate student, David Sullivan, and intern, Holly Lane.
For the past nine years, Let Us Farm has relied solely on cover crops to build the tilth of their soil. Steve explained that they use both winter and summer cover crops to provide all of their nitrogen and other plant nutrient needs. They do utilize organic fertilizers in their soil mixes for starting plants in the greenhouse – amendments such as green sand, blood meal, rock phosphate, and lime. Let Us Farm also greatly relies on a clever crop rotation to avoid diseases and nutritional problems.
Steve and Cecelia have a robust internship program, and this season they are hosting three – Aaron Sexton, Alex Drake, and Rachel LaManna. Their interns play a part in all aspects of production, as Steve is keen on training the next generation of farmers. Aaron led a demonstration on soil blocking and helped attendees practice making soil blocks, which was harder than it looks! Consistency is key when it comes to successful soil blocking because if they are too hard, the plants will have a difficult time rooting, and if they are too soft, they will fall apart. Aaron explained that you want the soil mix to look glossy-wet when making blocks. Let Us Farm exclusively utilizes soil blocks to start seedlings, which are grown on heated benches in their greenhouse.
As Steve led attendees around the farm, he pointed out their various high tunnels and hoop houses – all of which are cover cropped. Besides the hoop houses, the only other method of season extension Steve uses are hot caps – wax paper cloches – that he will place over individual plants such as squash, to alter their immediate micro-climate. The plants often grow through the paper, or once it is warm enough, they will either remove the hot caps or push them down around the plants as a kind of mulch. He also explained their conservation efforts and planting of pollinator strips. These strips are a mix of annuals and perennials to achieve four different nectar bursts over the course of the growing season, providing plenty of food for pollinators.
The group stopped at a couple different cover cropped parcels, where Doug and David demonstrated how to estimate plant-available nitrogen. This is done by cutting a representative sample of about one square meter within the cover crop stand, and separating out the different species present. There are nitrogen calculators that can then be used to estimate the pounds per acre of nitrogen provided by the cover crop. The other option is to send the vegetation collected into a lab to determine the nutrients provided. Cover crop mixes that Let Us Farm often involved both a grain (such as rye or wheat) and a legume (such as Austrian winter pea). The grain suppresses weeds and disease, and provides a structure for the legume to grow. Steve will mow and cultivate the cover crop into the soil before it goes to seed.
During the walk, Steve and Cecelia shared their seed saving efforts – especially with certain varieties of lettuce that they are particularly fond of – and spoke about their biggest pest issue, the Western spotted cucumber beetle. Attendees were also able to test drive some of Steve’s tractors and tour the old dairy silo he and the interns are reconstructing into an observation tower and potential housing. Even through the rain, it was easy to see Steve and Cecelia’s passion for caring for their land, for growing delicious food, and for training the next generation of farmers.
Summary by Angela Anegon
This Farm Walk is supported in part 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.