Solar Inputs on Mud Prairie Farm: A Study in Diversity and Energy Conservation

By: Woody Woodruff

As a farmer, I am well aware of the fact that input costs are a key factor in making a loss or profit from year to year. One thing’s for certain, those input costs are rarely ever decreasing over time. The fact is, in the last four decades inputs on the farm have increased by almost 700%.  One reason for this increase is the lack of an abundant supply or location of these resources. Energy is a prime example of an input that’s raising the cost in the production of food on a farm. We have energy costs in the form of fuel for tractors, combines, trucks, and all those tools that run off a combustion engine. We have propane inputs in drying grain or heating buildings. Farmers also have electric costs in lighting, heating, or running electrical tools. Unfortunately, in that same four decades crop prices have fluctuated from no change to a 300% increase. That is less than half in comparison to gains in input costs. Efficiency has become paramount to staying in business for farmers.  These imbalances in inputs have forced most farmers to make changes to their operations over the past four decades. My farm was no different.

One of the first wide spread things to vanish were small livestock operations. Input costs simply overwhelmed what the traditional markets were willing to pay. I had a small swine operation on this farm.  After several years of losses, the last hogs were shipped to market at a sizable loss. I used a small 20 foot by 40 foot farrowing building with a 6 foot concrete pit under it to capture the manure from the nursery pigs. After the pigs where gone I wasn’t sure what to do with the building and it set idle for several years, mainly due to the energy cost of using the building.  This was a time in agriculture that most farmers found it hard to find answers to what types of changes were needed to stay in farming. Most chose to expand the size of their operations in order to expand their bottom line. I decided to expand my mind instead. I call this my Agro-Ecology years. After taking classes in Agro-Ecology, Field Ecology, Local Flora, Aquatic Ecosystems, and Botany,  I wanted to apply what I was learning to my farm. I found inspiration from reading authors like Wendell Berry and Wes Jackson of the Land Institute. This time of reflection gave me a better understanding of the healthy living systems that need to exist to be able to minimize the dependency on these rising inputs. What has been sacrificed in most of our farm operations, mainly in lieu of short term survival, was diversity. But in long term sustainability in farming, diversity is the key to having fewer inputs.

My first step to diversity was starting a new prairie seed business to add to the corn, soybeans, wheat, and cattle I was raising at the time.  I also restored a prairie that once was located on the farm, called Mud Prairie. I found a mentor in Bill McClain, a prairie expert and Heritage Biologist with IDNR to help me with the proper steps to establish the prairie. A lot of plants that make up a healthy diverse prairie are extremely rare. Just planting the seeds in a prairie field was not very effective and extremely expensive. I now knew what to do with that old farrowing house. One of the classes that I took during my Agro-Eco college years was in Advanced Solar Design. For my class project I designed a passive solar greenhouse that stored the solar energy in the 5 feet of water that once was the pit of the farrowing house. The pit is all underground so it has an aspect of geothermal mass that helps keep the greenhouse temperature from dipping too low. The greenhouse has R-30 insulation in the walls and R-45 in the ceiling. There are double pain greenhouse glass windows facing south at an angle that takes advantage of the winter sun. This combination allows the greenhouse to grow plants throughout the winter without any needed utilities. I also use solar photovoltaic panels for charging batteries. The 12 volt deep cycle batteries run a pump for watering and lights for at night. The water in the greenhouse pit comes from the rain running of the roof, which is channeled from the guttering to the pit. I have bluegill swimming in the water to keep any insect larva at bay. The floor in the greenhouse is slatted so the air can move freely. This greenhouse has been the perfect place to start perennials in the fall after seed harvest which are then ready to plant by spring. Most all the different perennial prairie forbs I have collected grow well over winter and survive transplanting into the prairie in late spring.

Greenhouse Building


After I finished a couple decades of using the greenhouse for restoring the prairie, I started raising other types of plants to eat and sell from the greenhouse. Most all trees do well, either from seed or transplanted. Cool season vegetables do much better than the mid-summer vegetables over winter. Those mid- summer types of veggies just do not seem to fruit during the cool nights and shorter length of light during winter. When I transplant my sweet peppers from the garden in late fall, they continue to slowly fruit most all winter. I trim them back at the end of winter and plant them back into the garden the next growing season with an enormous amount of energy in the roots to start fruiting right away. It’s also been a great place to keep tropical plants like dwarf bananas and lemons. Smaller fruiting strawberries like day berries also fruit well all winter.  Transplanting these plants back into the garden with large root mass and leaf growth gives the plant a big advantage over weeds and insect damage. Having all those plants growing during the winter months also seems to ward away the winter blues as well.  If the sun is out and snow is on the ground, no matter the outside temperature the inside temperature is in the 90’s. At night it runs at around 50. The best thing about this greenhouse is it has no energy inputs like propane or coal based electricity. The initial inputs for this greenhouse were more of an investment in diversity of the long term farming system.

wintergreenhoue Forbsgreenhouse

I look at cover crops today in the same way I did the inputs for the greenhouse. This investment in cover crop diversity for my cropland in the long term will reduce the amount of inputs needed to grow a crop on this land. With fewer nutrients needed, less erosion control needed, less herbicide needed, and less tillage needed, there will be increases in water infiltration, more organic matter and healthier, more diverse soils to grow grains, to graze cattle, and to plant veggies and perennials from the greenhouse.