Commercial Sustainable Micro-green Production in a Northern Climate

Commercial Sustainable Micro-green Production in a Northern Climate

Summary

We began working on our grant project in May of 2015.  Though we are still in process in our research for this grant, the steps we have taken have produced astounding results. The increased quality of our product and the virtual elimination of loss due to plant health issues has greatly affected everything we do. We appear to have eliminated the drastic pH fluctuations.  It has been stable for months.

Note: Since receiving this grant both of our advisors, Ron Johnson (WI aquaponics specialist) and Jennifer Blasik(our county extension agent) have taken other jobs and have left the area.  We will need to make adjustments accordingly.

Also, we had a number of significant finacial set backs last year and have been unable to install the reverse osmosis system w/water conditioner as we are not able to add the additional funds as listed on the grant budget.  However, we are moving forward on everything else, with impressive results.

Objectives/Performance Targets

Summer 2015 – Purchase supplies and inputs. Prepare the four experimental grow beds by removing the rock currently being used as the filtration media and refilling both beds in one closed loop system with bio balls and both grow beds in a second system with expanded clay balls.  Install water filtration unit that will control the water pH.

Late summer, fall and winter 2015-2016 – Conduct project experiment. Because we are a business and need to maintain our scale of production, we will do our test in stages.

• Test commercially prepared soilless mix
• Test homemade peat/vermiculite/perlite/compost mix
• Test Sure 2 Grow pads
• Test Micro-mats
• Test Coir

Spring/Summer 2016-Outreach Projects

Spring/Summer/Fall 2016 – Finish up experiments, summarize data, complete outreach, write-up the final report for NCR-SARE.  Present information learned through our outreach efforts.

• Growbeds

Accomplishments/Milestones

Summer 2015.  In May we removed the rock base from the grow beds.  We scrubbed all the beds and water/fish tanks with a 35% peroxide solution.  We replaced the rocks with pH neutral Bio-media balls or clay balls.  We refilled the tanks with clean water.  It was immediately apparent the Bio-media balls were a poor choice for our system.  We have a two-tiered system that is built at a slope so the water flows from the top bed to the lower bed and then back into the tank by gravity. We place our seeded germination trays on the growing surface. Though pH neutral, the water flowed right through the balls causing trays at one end of the bed to flood and trays on the other end to dry out.  We attempted to resolve this problem by creating a series of dams made of brick to help manage water levels.  This helped considerably, however, we still struggled to maintain even moisture in the trays and had 4-8 or more trays dry out each week.  We eventually had to remove the Bio-balls and replace them with clay balls.  We will use the Bio-balls as part of the filters we build when we add fish to our system.

The beds that contained the clay balls have produced almost perfect results since the first day.  Since replacing the rocks in our grow beds there have not been any spikes in pH.  The pH has remained at 5.8-6.2 consistently, without adding chemicals such as pH Down or going through the tedious process of adding vinegar to the watering system.

• Next, we purchased a worm tea brewer and began making our own worm tea to fertilize our seeded trays.
• We then began experimenting with differant types of growing mediums, looking for the best soilless alternative.
• We planted all seven varieties of shoots and micro-greens that we produce in each type of medium.
• We used two peat based products.  One, a commercially prepared product, Sun Gro Natural and Organic.  The other, a peat, perlite, vermiculite, worm casting mixture we mix here.

The commercially prepared product was the most expensive and had the highest number of problems, including fungus gnats and other types of fungus we are unable to identify.  With both peat-based products we exprienced several problems with the finer stemmed micro-greens: kale, brocolli and mustard. The most common issue was damping off (withered stems).  There were also problems with mushy (rotten) spots.  We do not know the cause of this but suspect some type of fungus.  The heartier products like Pea Shoots and Sunflower Shoots did not seem to be bothered by these issues.  The moderately hardy radishes were only occasionally affected by fungus type problems and generally just during weeks of high humidity.

We found the prepared Natural and Organic product to be expensive, a carrier of pests, and have unreliable availability and have discontinued using it.  The peat mix we make here has proved to be an effective medium for Pea and Sunflower Shoots.  We have also been using it for two types of radish micro-greens while experimenting with other growing mediums.

The next item we tried was coir.  Though we have heard many good things about coir we found it to be heavy when wet, hard to break up, and we experienced the same damping off problems in the finer stemmed products as we did with the peat.  The cost/benefit of coir was unfavorable in our trials.

Currently we are testing Micro-mats, which we love!  Micro-mats are made from renewable wood fiber for organic production.  They are easy to use, pH neutral, do not add salt or other chemicals to the system, are clean and fully compostable.  They are light weight, and have produced superior results.  

The next growing medium to test will be the second type of growing mat.  Originally we planned to test the Sure 2 Grow mats, however, they have become difficult to obtain and I have not found them at a wholesale price.  At retail pricing it would be impossible to grow micro-greens at a profit using these mats.  I am also looking at other comparable mat type products and will be testing them next as soon as I find an acceptable substitute.

• Bio balls w/dam
• Bio balls w/dam
• clay balls
• Sample mustard trays. Peat/micromat side by side
• Sample of failed mustard tray in peat
• Healthy, partially developed mustard on micro mat
• Sample of healthy Kale on micro-mat
• Clay balls
• Rock that was removed
• Sample of failed broccoli tray in peat

Impacts and Contributions/Outcomes

Thus far, we have had the most success with growing the Pea and Sunflower Shoots in a mix of 1/2 bale peat, 4-1/2 gallons perlite, 4-1/2 gallons vermiculite and 1-1/2 gallons of worm castings.  We fill #1020 greenhouse flats 1/2 full with this mixture before adding our seed. We have had extremely consistent results with this mix.

We are currently testing this mix compared to micro-mats in our radish micro-green production.  Though a little too early to tell, it appears the micro-mats produce a cleaner, easier to wash product, but with slighly lower yields.

For the other micro-greens, the Micro-mats are by far the best product we have tested.  Ease of use, increased plant health, ease of harvesting, and reduced time washing have greatly impacted our micro-green production.  We are spending at least 10 less hours per week in labor across the board. We are now able to put more time into building our business.  There is consistent enough plant health to begin investigating improved harvest methods again.  We now have more time.  We are seeing improved potential for profitability.

Collaborators: