We have a 15-acre farm where we grow approximately 6 acres of vegetables that we market through a local farmers’ cooperative, farmers markets and an on-farm stand. Our main livestock consists of approximately 200 laying hens that are kept on a rotational pasture when weather permits, though we do have a small flock of sheep. In addition to vegetable and egg production we also produce and market fresh cut flowers, cut herbs and started vegetable, herb and flower plants. We grow our products in as sustainable a manner as possible. We are not certified organic but we use only organically approved chemicals on our produce when needed.
We have strived to operate our farm in a sustainable manner since we began operations in 1998. We use our own compost, sterilized, as our base for our starting medium, adding peat moss as needed. We have grass buffers between all of our production fields to reduce any potential for run off. We encourage our customers to return any pots and trays in which plants may have been purchased. These pots and trays are then sterilized and used again. For the past five years we have heated our greenhouse and home with wood which we cut from downed trees in many area sink holes. Any building that we add to our farm, or remodel, we use nearly all reclaimed materials. For example our newest addition, an on-farm sales stand, was built entirely out of reclaimed tin, windows, boards and posts. The only new products used were the screws and other fasteners needed for the project.
The goal of our project was to determine if it is possible to use the black soldier fly larvae as a replacement for the protein in the chicken feed. It was also to determine if any of the by-products would be useable in our greenhouse production. Black soldier fly larvae are commonly know as phoenix worms and are the larvae state of the black soldier fly, which is native to the Southeastern United States. The mature black soldier fly does not have the ability to eat, they live just long enough to mate and lay their eggs in food waste or manure. The eggs soon hatch into larvae which break down the waste into compost and a liquid by-product. Once the larvae reach the stage where they are ready to begin to pupate they emerge from the waste to try to find dirt where they burrow in and metamorphosis into adult black soldier flies. At the point where the larvae emerge from the waste is where it is possible to gather them up as a feed supplement for the laying hens.
The first step we took in our project was to obtain the black soldier fly larvae. We were able to obtain them via the internet where they were being sold as live lizard food, under the name phoenix worms. These larvae were then placed in a large plastic tub which we had filled with food and plant waste. Our first groups were not a success; the spring and summer was very cold and there was not enough heat and though the larvae did not die until winter when they froze, they did not grow.
The second spring we were able to introduce another batch of larvae to food and plant waste. We moved the plastic tub to the greenhouse where the summer temperatures were much warmer and were able to get a number of cycles of the black soldier fly.
As the larvae go through their life cycle they break down the food waste and create a large amount of liquid by-product. This needs to be drained from the tubs and kept off of where the larvae are in the tub. The liquid by-product is very plentiful and we have found that it is a useful fertilizer in our greenhouse. The compost also was able to be used as a plant starting medium.
The members of our farm were instrumental in the completion of this project. Lee Newman was able to construct a containment area for the project off of the chicken building, as well as an area in the greenhouse once it was determined the shaded area was too cool of an area for successful reproduction of the larvae. It wouldn’t have been possible to figure out the solution to the temperature and liquid collection problems without Anna Herzmann or Kyle Holthaus.
My results were not as good as I hoped; however with the continuation of the work for another year I have much higher hopes. I found that the temperature needed to facilitate the growth of the worms is not possible during a cool and wet northern Iowan summer. Moving the project to the greenhouse resulted in much better successes. The winter greenhouse temperatures, when not used for main production, are not high enough for the active growth of the larvae however it is warm enough to keep them in a dormant stage until it warms in the early spring.
We plan to continue with this project to better develop methods that work for us in Northeast Iowa’s climate. We were disappointed by our ‘loss’ in the first year, first by the extremely wet and cool weather we had but also in the time it took to put the understanding we had from our reading into application. We hope to have very good results at the end of this third year.
The larvae grow and reproduce much better with produce waste than with the less succulent leaves of grasses and plants. We are hoping to start the testing of how the larvae breakdown manure this summer now that we are able to get the insects to reproduce on their own.
We had originally planned to compare the use of plastic tubs compared to wooden crates but found with the amount of liquid by-product it would not be feasible. The cost of the large tubs has not been recouped yet, however they are the ideal container for the production of the larvae. The amount of larvae production has not reached a level to create a noticeable impact on the feed consumption of the chickens. The liquid by-product, however, has already replaced the organic fertilizer we had been using in our greenhouse production. I feel that once we are able to better get the process figured out the investment in the project would be able to be recovered over a period of 4-5 years by savings in feed and fertilizer in our operation. The repayment period would certainly be affected by the type of operation a farmer has and what uses they have for the by-products of the system.
The amount of larvae production has not reached a level to create a noticeable impact on the feed consumption of the chickens. The liquid by-product, however, has already replaced the organic fertilizer we had been using in our greenhouse production. I feel that once we are able to better get the process figured out the investment in the project would be able to be recovered over a period of 4-5 years by savings in feed and fertilizer in our operation. The repayment period would certainly be affected by the type of operation a farmer has and what uses they have for the by-products of the system.
We have informed many people about our project and the processes we were working through at our field day and other various farm visits. We had approximately 85 attendees at our 2011 field day where we were able to discuss our project and what our findings were at that time. We also spoke of our project with a group from the NIFF Local Food Tour. We will be having another field day in 2012 and will be publishing our final results after this summer on our website that has hundreds of visitors per year. We also update our progress on our face book account.