How The Kings Are Tricking Mother Nature
This winter the King brothers dug into a new project.
Season extension is an important part of the Freedom Farms business. Their goal is to provide farm goods year-round to their customers. The recent addition of livestock to their operation has allowed them to sell eggs, chicken and pork throughout the winter. Now, Tim King is working to significantly expand his produce season as well.
High on a south-facing hill above their farmhouse, they’re building a Walipini. In the language of the Aymara Indian tribe of Bolivia, the word Walipini means “a place of warmth.” Freedom Farms is located in the USDA Plant Hardiness Zone 5, which means low temperatures in the winter can dip to 20 degrees below zero. On the snowy hilltop where the Kings are building their Walipini, a place of warmth sounds pretty appealing.
Tim says: “I’ve been researching new ways to extend the season, and I’m excited about the Walipini. We want to be able to extend the season and grow year-round instead of just being a seasonal business. I currently use 13 high-tunnel hoophouse structures. My high-tunnels above ground are mainly used to overwinter crops. That means they are sitting there being stored. For example, I have carrots in the greenhouse. With the high-tunnel sheltering them from the cold, it doesn’t freeze enough to ruin them, and I can eventually go in and harvest them. My hope is that with the Walipini I can actually grow crops during the winter.”
The Walipini is an underground greenhouse dug six to eight feet below ground on a south-facing slope. A thick, earthen wall on one side and a lower wall on the front provide an angled roof, which is covered with a double layer of insulating plastic. This design uses both the thermal mass of the earth and the heat of the sun to create a much warmer environment than traditional above-ground greenhouses. At four feet below the surface, the temperature of the earth is consistently 50-60 degrees Fahrenheit. Solar energy and light filter through the plastic roof of the Walipini, and this heat is stored in the walls of the building and released at night. The roof is angled to absorb the maximum possible amount of the winter sun, which is low in the sky.
The Walipini was designed by the non-profit Benson Institute, which is dedicated to helping families in the developing world become nutritionally self-sufficient and improve their economic resources. It was important to the designers that the structure be one of low cost and high efficiency. The plans (available at http://www.bensoninstitute.org/Publication/Manuals/Walipini.pdf) utilize simple tools and building techniques but allow for maximum sustainability. In theory, a Walipini can provide fresh vegetables all year long.
The Walipini is a new concept and it’s just beginning to be explored in North America. Tim says, “We did a lot of research on the Internet, and then we took the concept and kind of made it our own. Our Walipini is pretty large, at 70’ x 20.’ We built it with concrete block instead of earthen walls, which we think will hold more warmth and solar energy. So far, most people have been using earthen walls, but when building with earth there is always the danger of collapse. This will be a permanent structure.”
A heavy snowstorm during the initial phase of building the foundation made it tough to get started, but after a few cold months, the plastic roof is on and Tim is looking forward to planting in his new underground greenhouse.
He says, “I’m going to have to experiment. There isn’t a whole lot of information out there right now. As soon as we get soil in, I’m going to seed it. We also have to work on our watering system. We plan to use rainwater to irrigate the crops inside. It’s something we’ve never done before. We’re experimenting with it. I understand the concept, so I think it should work. Right now, there is no definitive guide for what varieties to plant and what date to plant them in a Walipini in Pennsylvania. A specific guide would be nice. I guess maybe I’ll have to write the book. I keep records of everything I do, and eventually I’ll be able to help other people by sharing my experience. I’m willing to experience the growing pains first.”
“Every farm is different,” says Tim. “Even here in our local area, different farms have different ways of planting at different times of the year. Every farmer really has to figure out for themselves what works. I am always happy to give people ideas. When you are starting a new project, a rough idea is extremely helpful so that you don’t have to start from zero, but you have to fine-tune what you’re doing on your own land. We improve things here every year, and a big part of that is keeping records. We won’t stop until we have it perfect, which is hard with Mother Nature—but we’ll come pretty close.”
This article was originally published in the Feb. 2014 issue of Freedom Farms Magazine.