Growing Mushrooms on Local Agricultural Byproducts

PROJECT BACKGROUND

Wakarusa Valley Farm is a family farm that cultivates organic vegetables, fruits, and mushrooms. We currently have around 30 acres in cultivation and grow a wide variety of vegetables as well as berries and melons. For around 12 years, we have been growing gourmet mushrooms in several grow rooms at our farm. About a year ago we also began fruiting mushrooms in a space rented inside of a cave.

Mud Flood Acres is a family farm growing 9 acres of vegetables and corn. We are not certified organic but farm using organic principles and inputs.

Both farms participating in this grant have used cover cropping extensively since their beginnings (Wakarusa Valley Farm in 1987 and Mud Flood Acres in 2014). Neither farm uses synthetic chemical inputs and Wakarusa Valley Farm has been certified organic since 1989. When Wakarusa Valley Farm began growing mushrooms about 12 years ago, the finished mushroom compost became another helpful part of the soil building process, adding partially decomposed organic matter to fields and greenhouses and improving soil texture and water retention.

PROJECT DESCRIPTION

GOALS

Our primary project goal was to set up and test a system where a majority of the substrate used in Wakarusa Valley Farm’s mushroom cultivation are sourced from participating farms (Wakarusa Valley and Mud Flood Acres). We also hoped that Mud Flood Acres would be able to make additional income by growing corn as a food crop. Initially, we wanted to set Johannes Family Farm as a milling center for our sunflower cultivation and for other small farms who wished to experiment with specialized crops needing hulling, but as reported earlier Johannes Family Farm was unable to participate in the grant.

PROCESS

Our experimenting process began with planting sunflowers (.63 acres the first year and 4 acres the second) and corn (3 acres the first year and .8 the second) at Mud Flood Acres. The first year’s larger plantings were made with an antique grain drill purchased prior to the grant process, while smaller fields were planted with a walk-behind Earthway seeder. Finding the plant spacing achieved with the antique seeder to be slightly less than satisfactory, and considering the maintenance needs to keep such an old piece of machinery functioning properly, we began considering buying a newer 2-row planter for sowing our sunflowers and corn. Cultivation this first year was done primarily with an 18” wide walk-behind tiller. We found that sunflowers had a much better capacity to overcome weed pressure, and ended up losing a couple small (<.5 acre) plantings of open pollinated corn to weeds. Sunflowers also tolerated poorer soils better, and formed harvestable heads in all growing conditions experienced. Corn was left on the stalk to dry to storage-appropriate moisture. Sunflowers were a little trickier, and were planted in smaller succession plantings. We found that when rain was moderate to frequent, the backs of the heads would collect rain and cause seeds to rot. Thus, we constructed drying racks and picked sunflowers as needed to prevent rot and loss of the crop to birds and insects, and brought the heads into Wakarusa Valley Farm’s hoophouse to dry. The 3 acres of corn planted the first year, we harvested by hand, dehusking as we picked, and stored as much as possible in food grade 55 gallon barrels, shelling it over the winter. At first we shelled it with a small hand cranked sheller while we searched for an appropriate motor-driven sheller to make the process quicker and more efficient. Unable to find a newly manufactured sheller on the market in the US, we bought a sheller directly from a farm implement factory in China and put a 1 hp electric engine on it. With this sheller, we are able to shell up to 500 lbs of corn in an hour.

With Johannes Family Farm unable to participate in the grant process and with all the insect and rot problems we discovered with growing sunflowers, our objective with that crop became simply to get a high quality substrate component that is capable of replacing the sunflower shell we had been getting from a mill in Colorado. Once harvest was complete, we were able to begin trials of the different substrates with mushrooms. We came up with 6 substrate formulations, 1 “control” that represented a common day-to-day mix used in our mushroom cultivation, 1 utilizing primarily shell from the Colorado sunflower mill, 2 utilizing primarily corn cob (one with the softer white cob from our hybrid corn, one with the harder red corn from our heirloom Bloody Butcher corn), 1 utilizing primarily our farm-grown sunflower shell, and one utilizing an equal mix of farm-grown shell and corn cob. As were not able to ready enough substrate by the beginning of spring to trial Shiitake, a slower growing, less heat tolerant species, these first trials were only performed with Oyster mushrooms, inoculating 10 blocks of each substrate formulation. The rest of the trialing would have to wait until the next winter. Meanwhile, we considered more efficient ways to grow and process our substrate crops.

After completing one year of cultivation and harvest of both sunflowers and corn, we decided that if we were to invest in mechanization of one part of the growing process, planting would make the most sense. One planter could plant both crops quickly and with proper spacing, and it would be cheaper and easier to maintain than a corn picker, which we had considered purchasing during the grant formation and application process. Hand harvest of corn took some time, but 60 to 80 lbs could be harvested in an hour, and with the sale of finished cornmeal for $1-$2 per pound, the harvest and processing time is worth it. Cob turned out to be about 1/3 of the volume of each ear of corn, and this has varied with different varieties and growing conditions.

We actually found sunflowers to be quite easy to harvest by hand. During our first winter, we struggled a bit to find an efficient way to process the sunflower heads and remove the shell. We began by either scraping the shell from the head with a flat metal tool or threshing the shells by pounding them with a sledgehammer. After performing the first trial with sunflower shell prepared with these laborious methods, after the second year’s harvest we began running whole heads through our small wood chipper. This made post-harvest processing much more expedient, but left more of the soft, foamy, sunflower head in the final product, so we decided to trial substrates prepared with both methods of sunflower threshing in our remaining mushroom growing trials. Corn cob was also run through the wood chipper to break it up into small pieces able to be grown through and digested by mushroom mycelium.

Our growing methods also improved during the second year of the grant process. While we didn’t get our planter shipped and assembled in time to plant corn, we did successfully plant the majority of our two acres of sunflowers with it. We also improved our weeding techniques, adjusting a tool bar with rotating tine cultivators that Wakarusa Valley has had for years to allow us to weed the sunflowers from the tractor. With the growing process streamlined, we were able to harvest a decent amount of sunflower shell and conduct the remaining trials on three more types of mushrooms and have additional shell and cob left over to help fill our regular mushroom substrate needs.

PEOPLE

Larry Tukel, a neighboring farmer, gave us advice on planting sunflowers (planting dates, information about machinery, pest issues, etc.), as he had formerly grown them on the ground now rented by Mud Flood Acres. Jake Johannes, though he was unable to participate in the grant, also consulted with us about organic cultivation of sunflowers and corn, both crops he has grown, and proper storage and processing of grains.

RESULTS

Our project has two sets of results, those pertaining to the cultivation and harvest of sunflowers and corn and those regarding the use of these field crops as a growing medium for mushrooms.

Organic corn and sunflower cultivation, while today normally fully mechanized from planting to harvest, have a widely established body of knowledge around them, so I will only briefly discuss our yields and findings of the past two growing seasons for these crops. The first year, we obtained yields of corn ranging 80 bushels/acre with a hybrid variety grown on poorer, somewhat weedy, clay rich transitional ground with likely inadequate nitrogen. Our relatively tiny 1/8^th of an acre planted with Bloody Butcher seed saved at Mud Flood Acres every season since 2011 produced the best, yielding around 112 bushels/acre. We believe this was largely due to the high fertility of the organic field it was grown in, favorable growing conditions, and an early planting date (first week of May). Bloody Butcher has proven to be a reliable and somewhat drought resistant OP variety and performed well the second year also, weathering lodge-inducing storms, less favorable growing conditions, and an early planting date to yield around 90 bushels an acre the second year we grew it. For every bushel of corn grown, roughly ¼ bushel of chipped corn cob was yielded, depending on variety and weather conditions.

Sunflower yields were a somewhat different story, as we ended up using the entire sunflower head by the second year of the grant as a mushroom substrate and we never obtained a usable human food product from this crop. The first year, sunflower substrate yields were 1260 lbs/ acre. Then during the second year, considering the entire head we were now using as a substrate, yields were 1640 lbs/ acre.

The core goals of our grant rested not only on growing successful crops of sunflowers and corn, but also on finding out how the sunflower shell and corn cob we grew performed as a growing medium for mushrooms. Ultimately, we trialed four different mushroom varieties on 6 different substrate combinations each. We made 10 3.5-4.5 lb blocks for each variety of each different substrate mix and measured the yields from the first and second flushes (combined in results) of each variety. The mixes and yields were as follows:

Pohu (Pleuroteus ostreatus)

1. 70% pounded farm-grown shell, 30% sawdust .54 lbs/block
2. 70% chipped farm-grown shell, 30% sawdust .64 lbs/block
3. 70% Colorado milled shell, 30% sawdust (control) 17 lbs/block
4. 70% soft white cob, 30% sawdust .36 lbs/ block
5. 70% hard red cob, 30% sawdust .35 lbs/ block
6. 40% cob, 40% pounded farm-grown shell, 20% sawdust 1 lbs/ block

Shiitake (Lentinula edodes)

1. 50% cob, 50% sawdust .78 lbs/block
2. 50% pounded farm shell, 50% sawdust .90 lbs/block
3. 50% chipped farm shell, 50% sawdust 1 lb/block
4. 40% woodchip, 40% sawdust, 20% Colorado shell (control .65/lbs block
5. 25% cob, 25% pounded farm shell, 50% sawdust 08/lbs block
6. 25% cob, 24% chipped farm shell, 50% sawdust 33 lbs block

Black Poplar (Agrocybe aegerita)

1. 70 % cob, 30% sawdust .26 lbs/ block
2. 70% pounded farm shell, 30% sawdust .50 lbs/ block
3. 70% chipped farm shell, 30% sawdust .78 lbs/block
4. 35% woodchip, 35% Colorado shell, 30% sawdust (control) .27 lbs/ block
5. 30% cob, 40% pounded farm shell, 30% sawdust .59 lbs block
6. 30% cob, 40% chipped farm shell, 30% sawdust .59 lbs / block

Hericium erinaceus

1. 70% cob, 30% sawdust .49 lbs/ block
2. 70% pounded farm shell, 30% sawdust .25 lbs/ block
3. 70% chipped farm shell, 30% sawdust .60 lbs/block
4. 30% woodchip, 40% Colorado shell, 30% sawdust (control) .59 lbs/ block
5. 30% cob, 40% pounded farm shell, 30% sawdust .53 lbs block
6. 30% cob, 40% chipped farm shell, 30% sawdust .62 lbs / block

Compared to conventional systems previously used on the farm, we found the farm grown substrates to be highly favorable. Only in the oyster trials did the control blocks yield better than the farm grown substrate mixes, and it is possible that comparative yields would have evened out over time if more flushes were recorded since oyster typically fruits over 3 or more flushes. Another factor may have been an insufficient soaking time for the farm-grown shell (the Colorado shell soaks up and holds moisture more readily than our farm grown shell) put into the substrate mixes, causing too dry of a final substrate and lowering eventual yields. Outside of recorded trials, we found the farm-grown shell to be as good or better of a substrate for oyster when compared with the Colorado shell. The cob made a good addition to the mix and while not suitable for higher (>40%) proportions of an oyster substrate, it probably provides a longer lasting component of the substrate that can feed higher late flush yields. In our shiitake trials, the control performed the lowest, demonstrating the potential of our farm grown substrates. We would like to reach 1 lb per block or greater with shiitake, and 3 of the farm-grown mixes reached this threshold. Again, a mix between corn cob and farm grown shell proved to be a highly favorable substrate mix. Corn cob, due to its dense and slowly degrading nature, is probably most suited to the slower fruiting shiitake, though it should still be mixed with sawdust and shell, or possibly woodchips. For black poplar, .5-.75 lbs per block is considered a good yield, and all but the 50/50 corn cob sawdust and control mixes reached this mark. Due to the tenuous nature of Black Poplar’s mycelium and its fairly short growth period, sunflower shell probably makes a slightly better substrate component than corn cob, though clearly the cob/shell/sawdust mixes produced good yields. We have found hericium to have similar yields to black poplar, with .5-.75 lbs per block considered good. The chipped farm shell mix was near the top of production, but the chipped shell/cob/sawdust mix performed slightly better. Corn cob was shown to be a very favorable substrate component here, almost matching the production of the chipped farm shell. With all trials, the value of diverse substrate components was shown, as cob/shell/sawdust mixes repeatedly yielded the greatest amount of mushrooms.

DISCUSSION

We learned much about the cultivation of sunflowers and corn during this grant, as well as about the feasibility of using these crops for mushroom cultivation. Sunflowers proved to be easier to grow than corn and are more tolerant of weeds, and poor soil and low fertility. Sunflowers will also sprout in subfreezing temperatures, tolerating nights that get into the low 20s. By planting early and staggering plantings, beginning in March and continuing through the third week of July, we could plant a (relative to our methods) larger area and harvest it by hand as the sunflower heads matured. In our second season, we were able to grow sunflowers on 4 acres and harvest them by hand over a 4 month period. After some experimenting, we found that we could use the entire sunflower head as a mushroom growing substrate by putting it through a small wood chipper. The sunflower head consists of four parts, the kernel, the shell, the hull surrounding the shell, and the foamy backing. While we were unable to get an edible food product from the sunflower crops due to Johnnes Family Farm’s inability to participate in the grant with their mill, our primary focus was to develop a substrate source and we were quite successful in this respect. We were able to produce the sunflower substrate for 38 cents a lb, a competitive price for substrate. This substrate is better, cleaner, fresher, and less likely to cause contamination in our cultivation process than the dusty partially milled shell we had been getting from the mill in Colorado.

For its part, corn cob turned out to be a decent substrate when used as a smaller proportion (generally <30% of the mix, somewhat dependant on the mushroom variety) of the mix. Coming up with a cost for the corn cob substrate would be somewhat subjective and arbitrary because it is a true byproduct and the profitability of growing small plots of corn using our methods depends on the proper harvest, storage, processing, and marketing of the corn itself. We were pleased with this process and found it to be economically sustainable as a supplemental crop to add to existing produce sales at Mud Flood Acres, especially in the more financially difficult winter and early spring months. Products made with our corn have included cornmeal, fresh masa, and tamales produced in Wakarusa Valley Farm’s certified kitchen.

The field crop and mushroom growing trials conducted during this grant process have allowed us to stop buying sunflower shell from Colorado and added corn cob to our substrate repertoire, the shell eliminating our need to spend thousands of dollars a year and the cob potentially cutting back the need for making our own woodchips. The shell substrate we produced is better than the shell we were buying, and has added an interesting and enjoyable job harvesting sunflowers for a good part of the growing season where less bending to the ground is involved. Of course the farms have also been brightened up with fields of sunflowers, to the notice of many passersby.

Our corn cultivation techniques will continue to improve, but with the streamlining of the process last year and everything we have learned about planting, cultivating, and processing corn into an end product, corn will become a yearly crop at Mud Flood Acres. We plan on increasing the area devoted to corn as we add food grade storage and outlets for direct marketing our heirloom cornmeal (at $1-2/lb).

The advantages of implementing this project include obtaining a better, cost effective substrate that can meet most of our needs for an “agricultural byproduct” substrate which provides consistent, good yields when used to grow the mushroom varieties we cultivate at Wakarusa Valley Farm. We were able to keep more money on the farm and offer more work to the farm’s employees. The corn provided Mud Flood Acres with additional income and added variety to our winter vegetable subscriptions. Hopefully we will be able to continue to expand the cultivation of both of these field crops and the marketing of the corn products.

Some disadvantages we found were that the more acreage we planted, the more necessary it became to implement tractor driven planting and cultivation, and this became one of our primary challenges during the project. The drying of sunflowers also takes up more space in the hoophouse than the milled shell from Colorado did, and it is difficult to minimize the access rodents and birds have to the shell throughout the winter. Planting for both crops also occurs at a busy time on both farms when many vegetables are also being planted. However, by planting with a tractor pulled seeder, the issues this causes can be minimized. Since harvest occurs during the later parts of the season, and corn stores for a certain amount of time in the field, it has not been much of an issue in terms of time-conflict because there is generally less vegetable work to do on our farms in late summer and fall.

OUTREACH

This winter we presented our grant process and findings at the Missouri Organic Association’s annual conference and the Great Plains Growers’ Conference. Around 25 people attended the MOA presentation and 35 saw our presentation at the GPGC. We do not currently have any further plans to share our project and its results but are open to presenting the information to any interested parties or writing up a summary for the SARE website. We have included pictures of the process with this report.