Growing in a high tunnel all year is difficult. Cool season crops need air circulation to avoid disease. We found that using automated sidewall curtains worked as well as when we manually opened and closed the sidewall curtains. Kale, collards and spinach grew successfully in the fall, winter, and spring months so long as we opened and closed the high tunnel sidewall curtains based on temperature, humidity and wind. All three crops tested grew similarly which showed that successful fall, winter, and spring crops can be grown from a remote setting in our 24′ – 26′ wide by 80′ long high tunnels.
In order to use the automated side wall curtains using solar power we had to purchase and install Aegris Solar Touchscreen Environmental Controller, 1 – 100′ temperature sensor, 1 – 140 Watt solar panel, 1 – 12 volt battery, 1 low voltage motor, 1 humidity sensor, 1 wind sensor and 1 guide pipe along with the hardware. All components were purchased from Advancing Alternatives and were compatible. The cost for the solar automated system cost $3,606.80 where as the hard wired automated system also purchased from Advancing Alternatives cost $1,817.00. According to my husband both were easy to set up, as was programming the settings for opening and closing of the side wall curtains. We had two incidences when none of the sidewall curtains; solar powered, hard wired or manually operated worked. This occurred when we had a heavy wet spring snowfall, but once the piled up snow was removed all three systems worked fine.
Most of the produce grown for this experiment was sell-able, meaning that the leaves did not have significant damage due to insects, critters, or disease. While the production appeared higher in the manually opened sidewalls and the damage appeared slightly lower, this study was not designed to predict with confidence the difference among the 3 systems though it was recorded. In each 4′ by 10′ bed, the Winterbor Kale harvest ranged from 142.5 pounds to 160.5 pounds, the Tiger Collards overall harvest equaled 80.75 pounds to 86.5 pounds and the Corvair Spinach harvests came in at 100 pounds to 110 pounds. Overall damage from the three crops grown ranged from a low of 3% to a high of 11% over fall, winter, and spring weekly harvests. The spinach harvests saw the most damage due to the fact that the leaves tends to grow closer to the ground and since most of the damage appeared to come from mice, voles or moles.
We found that we loved the ease of use with the automated sidewall curtains so much so that we plan to install the automation on our remaining high tunnel and on any future high tunnels. The automation allows us the freedom to go away on vacation during fall, winter, and spring growing seasons.
With over 600 high tunnel growers in West Virginia few attempt to grow during the fall, winter, and spring due to the struggles of opening and closing sidewall curtains requirements for successful crop growth. Although the initial cost for setting up the systems are high, we have found the automation to work as well as if we were at home each day to open and close our tunnels throughout those critical weather changes. In 2019 West Virginia Small Farm Conference attendees learned about our SARE grant proposal and we shared how to use automated sidewall curtains to grow year round.
The goal of this project are to decrease the amount of crop failure and disease due to temperature fluctuations and lack of adequate ventilation; reduce labor cost; and to increase crop health, yield, and quality of products through the use of an automated ventilation system powered by solar energy. With over 600 high tunnel growers in the state of West Virginia, educating and teaching growers by modeling how to install and use automated air circulation systems utilizing solar energy will improve their production during the fall, spring and winter months. This knowledge could potentially encourage local growers to produce year-round resulting in a more sustainable farm operation. Good agricultural practices including proper ventilation and disease prevention increases both the quality and quantity of the sellable product. Simply having a high tunnel does not guarantee crop success or increased profits. Crop management is vital.
The objective is to compare crop health, yield, quality and labor input for two automated high tunnels, one solar- powered and one hard wired, and one with a manually operated side wall curtain all that will be operated for ventilation to control humidity and temperature.
Data will be collected by comparing the amount of product produced during the winter, early spring and late fall crops in a high tunnel using automated air ventilation and solar power vs. a control high tunnel that relies on manually monitoring the temperatures and adjusting for air circulation.
A common challenge for all high tunnel growers is maintaining an optimum growing environment during cold season production. Growing produce during these times of the year is challenging because the weather can fluctuate within a high tunnel from below freezing to over 100 degrees depending upon outside temperatures and how sunny it is on a given day. Crops can either be killed due to temperature extremes or compromised by disease due to lack of ventilation.
Many high tunnel growers live in remote locations in West Virginia, which is too far to affordably connect to electrical grids. In addition, some high tunnel growers live or work too far away from their high tunnels to monitor and adjust the exposure to temperature fluctuations throughout the day and night.
Automating side wall curtains will increase moderate growing temperatures for cool season crops. Using a renewable energy source, solar power, to power those needs allows for high tunnels in remote areas where there is no other affordable energy source to power the equipment.
As a local produce grower who has grown and sold a variety of fruits and vegetables within West Virginia since 2011, I have found few if any other local high tunnel growers that even attempt grow year round due to this very problem. I too have found it difficult to leave or even go on vacation. Summer growing in high tunnels is fairly easy as growers can keep the tunnels open for air circulation and temperature maintenance all summer long. This method will not work for fall, winter, or spring high tunnel growers due to varying temperatures and the build up of humidity. I learned this lesson first hand, in the fall of 2016. I left for a four day vacation and came home to a complete loss in my high tunnel due to the high temperatures in the high tunnel while I was gone. Although the outside temperatures during my vacation ranged between 30-34 degrees the inside temperature of the high tunnel got too hot for my crop of sugar snap peas to survive.
Our farm, T L Fruits and Vegetables, produces over 35 different fruits and vegetables for a online market, we sell at two local farmer markets, we offer onsite sales, and we have a summer weekly CSA. Gross sales this year are $35,000. We have three high tunnels where we grow produce year-round with additional acreage under production. We began our farm in West Virginia in 2011. As produce growers we work with many local growers, volunteers, interns, year-round employees and collaborate with Dr. Lewis Jett on research projects with WVU.
We are using three gothic style 24′ – 26′ wide by 80′ long high tunnels located at T. L. Fruits and Vegetables farm in Caldwell, WV. All three high tunnels are in a north south orientation using a double layer 6 mil polyethylene film cover. All three stationary, single bay, gothic style high tunnels are located at the same elevation offering almost identical environmental conditions and temperatures. In all three high tunnels the temperature and humidity will be monitored and recorded.
In High Tunnel A – Automated side wall curtains are being powered by solar energy
In High Tunnel B – Automated side wall curtains are being powered using on grid energy
In High Tunnel C – controls for side wall curtains have no automation
On August 1, 2018 three growing areas were prepared for a 4′ x 10′ in all three high tunnels. Corvair Spinach was planted by seed 6″ apart in four rows, Tiger Collards transplants were planted 12″ apart in four rows, and Winterbor Kale transplanted were planted 12″ apart in four row in all three high tunnels. Temperature and humidity is being recorded using remote data sensors.
Within a month (9/6/18) insect damage was noted in all three high tunnels with High Tunnel A having the worst amount of visible damage. All plants were dusted for worm control. Our first harvest was completed on 9/9/18 with most of our kale and collards leaves unsellable due to worm damage.
The next two weeks we found white flies, voles, and a rabbit damage so an all purpose insecticide was used as well as chicken wire installed on all sidewalls.
11/10/18 was our first really cold day in WV. Outside temperatures dropped to 30 degrees with inside temperatures ranging from 48 degrees to 52 degrees throughout the day. On 11/16/18 we experienced freezing rain and ice, so much so that the sidewall curtains were unable to open due to the amount of frozen ice on the poles. After chipping off the ice all of the side wall curtains were operational. The freezing rain is an unusual situation for us but we were glad that we were home when it happened so we could solve the problem as it occurred.
We harvest all of one crop on the same day based on when we receive orders. Supplying fresh produce on the day it was picked has always been our goal. When harvesting we use a different color tub for each high tunnel and each crop. Once the crop is brought into our wash room it is sorted and weighed and then bagged for our customers. Using a data table we are tracking sellable product by the ounce, unsellable product by the ounce and total product picked by the ounce. Since we sell to a variety of customers we have found a market for our unsellable produce. A local coffee shop makes green juice drinks and they are willing to buy leaves that are slightly damaged. We also have a local Waste Not, Want Not program that allows low income customers in our area to buy surplus farm products at a price they can afford.
In early fall and then again in late spring we had issues with cabbage worms, slugs, and a new farm puppy, but all three areas had similar problems. A unique problem we had in High Tunnel A and B was with moles and mice. For some reason we did not have moles or mice in High Tunnel C. We had to replace plants in both high tunnels due to damage from critters which did not appear to be a problem in High Tunnel C. Incidentally High Tunnel C is close to our barn which is where our cat lives. Both the kale and the collard greens were harvested 34 times throughout the experimental period, or once a week starting on September 10, 2018 through May 10, 2019. The spinach was planted by seed, so other than a few baby leaves harvested in the fall our first substantial harvest was made in early March for a total of 10 weekly harvests. By early May the kale, collards, and spinach were bolting.
We found that throughout the winter months we were able to maintain and keep the temperature with a five-degree variance. The humidity was more difficult to maintain since all the other crops planted within each high tunnel varied so it is believed that this caused the humidity levels to vary. We used Acurite wireless temperature and humidity sensors with a weather station display for recording the data. On most days this system worked fine, but whenever the wind picked up, which it did for most of our winter, we had trouble collecting reliable data.
Overall the results from production of Winterbor Kale, Tiger Collards, and Corvair Spinach were similar in all three high tunnels. Quality of product as well as quantity of product was measured. Each week we would use harvesting tubs to harvest all three crops from all three high tunnels. To avoid confusion we used three different tubs, one for each crop variety using the same color tubs for each high tunnel. Once the crops were harvested we weighed each tub and then subtracted for the weight of the tub. After recording the date of the harvest, the crop that was harvested we then sorted the greens into three piles; pile one held leaves that were near perfect and that we could sell at our top dollar price, pile two were leaves that were not perfect but we could still sell for a lesser price, and the third pile were leaves that were either diseased or damaged and thus we were unable to sell so we fed to our ducks or put in the compost pile. After all crops were sorted we did the math; what percent of the overall harvest was sellable, what percent of the crop was imperfect but still sellable and what percent of the harvest had to be tossed. Our unsellable products ranged from 3% to 11% after three seasons of weekly harvesting. Most of the damage came from critters such as mice, voles, or moles. All three of these pests are problems for high tunnel growers especially during the winter months as they seek the warmth of high tunnels especially if there are crops to eat. Each week had similar harvest results from all three high tunnels. For example, the total pounds of kale harvested from High Tunnel A (the solar powered automated side wall curtains) equaled 142.5 pounds of which 137 pounds were sellable leaves. This gave us a 96% of useable or sellable harvest versus only 3% unsellable. I should note that we have secured a market for our slightly imperfect leaves as juicing greens so we tend to have very little waste when growing leafy greens. Our highest percentage of loss came from the spinach crop as those leaves grow closer to the ground and are more susceptible to damage from mice, voles and moles. Overall very little of any of the crops were unsellable or were tossed during our experimental period. As a farm we have grown year round for years but this was by far my most profitable winter. Based on what we learned we have since added a winter market to our weekly sales and a winter CSA.
Opening and closing sidewall curtains is the key to successful growing for the fall, winter, and spring harvests. The two automated curtains were easy to program and basically maintenance free. Most of our time was spent walking to and from the manually operated sidewall curtain high tunnel. As it turned out this high tunnel was also the farthest from our house. During the winter months we had to dress for strong winds, rain, sleet, snow, or ice. Most winter days we made this trek two to three times per day. The automated side wall curtains worked well until we had deep snow falls. When we had snow accumulation the automated curtains would try to open but would be unable to do so until we removed the snow along the sides. This meant overriding the automated system until we could get all the snow shoveled off. Of course, manual operation of side wall curtains is also curtailed until the accumulation of snow is removed. We were pleased that even with the heavy snowfalls the solar powered system worked throughout the season without a problem. By the end of the first winter we had most of the kinks worked out for collecting temperature, humidity, and for opening and closing the sidewall curtains. Both my husband, our farm employees and myself all agreed that having the automated system was preferred over manually opening and closing for high tunnel sidewall curtains.
In the past we have hired workers to come out to our farm to open and close the high tunnel side wall curtains. This cost us quite a lot of money because the weather changes quickly within and outside a high tunnel during a day. If the weather is below freezing but sunny you still need to open the side wall curtains and then close them back in the evenings. This required us to pay employees to stay from sunup to sundown if we were out of town. The automatic side wall curtains worked perfectly unless you had significant snow fall. On those days we would still need to have someone available for successful winter growing.
Due to the grant this last year we stayed home for most of the fall, winter, and spring growing season to ensure that all the data was collected. We spent more time this year maintaining the adequate temperatures in our high tunnels and thus had our best production season. Due to lack of other winter produce growers in our area, we were able to easily sell all that we could grow. In fact, we have doubled our production planting of Winterbor Kale and switched to a higher producing collard green. The spring spinach was superior to any we have produced in the past, so we have doubled our spinach planting area too. The biggest lesson learned was to start the spinach seeds earlier to hopefully increase our fall spinach production. We are also trying a few new varieties of spinach to see if that too makes a difference in production. All three crops were in high demand, so we plan to incorporate all three into our yearly production schedule.
What have we learned:
1. The equipment we used for collecting temperature and humidity was not reliable. In the future we will need to manually read from each high tunnel or purchase a higher quality product that will work in our winter extreme weather. We had more trouble with this equipment working than with any other part of the experiment.
2. The planting date for spinach might have worked if we had used transplants rather than seeds. By the time the spinach plants emerged the weather was too cold, and the daylight hours were too short to offer any measurable harvests.
3. The Tiger collards went to seed very early and we have had another variety recommended which we are trying this winter.
4. Controlling for mice and moles is necessary as all crops suffer due to their damage.
5. Plant more of all crops; the demand for fresh greens was higher than what we could offer.
6. We would like to add an automated side wall curtain to our manually operated high tunnel
7. The snow accumulation along the sidewalls is a problem and we have submitted this problem to engineer of the automated sidewall curtains
8. We still have a ventilation problem on high wind days in our location. This is something we will need to address this year with roof vents or circulation fans.
As Richard and I discussed our results from this experiment, we decided that two things seemed to really make a difference: staying home for the length of the testing period and paying close attention to weather changes, humidity, and wind really improved our overall harvests. The three crops we choose to grow also played a big role in the success of our growing season. Based on the success of our SARE experiment, we have since increased our winter production of all three crops and still we are unable to meet the local demand for winter greens. Our biggest production numbers came in early spring. When most other growers in my area were beginning to seed their crops we were harvesting pounds of lush greens for the market. The quality of spring products were amazing. I think that the efforts made in late summer to ensure that we had plants ready for the experiment made all the difference. The end of summer is always such a busy time of the year for a grower, that it is easy to skip this step. Having healthy plants growing early really made all the difference in the success of fall, winter, and spring harvests.
The goal of our project was to decrease crop failure due to disease, temperature extremes, lack of ventilation, reduce labor costs, improve the quantity and quality of products grown and to encourage other growers to try growing year round.
Richard and I feel agree that the experiment had a positive result since we had our most successful fall, winter, and spring crops based on nine years of growing year round. We found that solar automatically powered sidewall curtains worked as well as hard wired automatically powered sidewall curtains which also worked as well as manually opening and closing sidewall curtains. Many growers in our area, as well as ourselves, predicted that snowfall and cloudy days would inhibit the solar powered sidewall curtains from operating successfully. Regardless of the lack of sun and heavy snowfall they were able to work as well as the hardwired curtains. The solar powered system costs almost double the cost of a hard wired automated system, yet it is an excellent option for those who have high tunnels in remote areas or for those like us who try to use solar energy for all our energy needs.
Over the past nine years we have spent a lot of time opening and closing our manually operated sidewall curtains with three high tunnels for eight months out of every year, but we never really paid much attention to how much time this really took until we started to compare our time spent for this experiment compared to the automated curtains. The simple math would be eight months with an average of 30 days per months and having to open and close the sidewall curtains at a minimum of twice per day would equal to 480 trips for just one high tunnel, and we have three! Most fall days we had to only open and close once or twice a day, but in the winter we would have had to make this trip three or four times per day. The worst trips to open or close the high tunnels are on the windy cold nights. We would take turns, similar to when we had to get up in the middle of the night for crying babies so many years ago! The spring is most critical for high tunnel growing in West Virginia because the weather fluctuates greatly; 60-70 degrees during the day and down to 20-30 degrees in the evenings. The freedom of automated sidewall curtains would allow us time to work away from the farm during the day or even travel during these three critical growing seasons of the year. In the past we have had to rely on paid labor to open and close our high tunnels if we choose to leave the farm for the day or for vacation. So if we take the conservative number of 480 trips x $12 per hour for labor our total cost would have been $5,760. This certainly makes the case for spending the cost for installing automated side wall curtains.
Richard and I have found that the automated system for sidewall curtains is a preferred method for controlling the temperature in high tunnels. It allows us to leave our farm during the critical periods of the year when temperature control determines crop success or failure. The automated system is not perfect, but it allows for extreme temperature changes to be moderated. If there is significant snow fall then all high tunnel sidewall curtains are inhibited from opening and closing.
Although we saw no significant differences in the three crops we tested we did however find that the automation works just as well as manually opening and closing of the sidewalls. This knowledge gives the growers confidence to successfully grow crops throughout the year without the need to always be home each and every day.
Although I have no first hand knowledge of any other growers utilizing this system I have had the opportunity to share this system with over 100 growers and most were impressed with the system. Many shared their desire to install this type of system but I do not know if any followed through with the actual process.
Education & Outreach Activities and Participation Summary
On February 14, 2019 I was invited to share my SARE project at the West Virginia Small Farm Conference during a three hour High Tunnel presentation organized by Dr. Lewis Jett from WVU. Our conference room was filled to capacity with over 50 participants. I spoke to the group of producers while sharing my prepared Here Comes the Sun PowerPoint presentation. My presentation included what SARE stands for, how to apply for a grant, what a SARE grant will fund, a summary of my grant proposal, a detailed explanation of the grant objectives, what the experimental procedure entailed, what I have learned so far from my experiment, and what I am hoping to learn in the future. We had a good discussion during my presentation with multiple questions from the group. Throughout the three days of the conference I had numerous producers ask me follow up questions and advice on applying for a SARE grant. During my presentation I had passed out two handouts from the SARE organization on grant proposals and all of my copies were taken so I believe there was a high interest in future grant applications.
On Tuesday March 14, 2019 we facilitated a Greenbrier Valley High Tunnel Workshop at our farm from 1-5:30 p.m. The event was advertised by WVU Extension Services, NRCS, and Dr. Lewis Jett a WVU Horticulture Extension Specialist. We had a big turnout with over 50 visitors ranging from local growers, professionals in the field and a representative Rimol Greenhouse who came in from Ohio. We spent the first part of the tour discussing the SARE grant application process, details about our specific proposal, how we set up our experiment and recorded our results, shared out data from the experiment and then toured each of the three experiment high tunnels. Throughout the tour I answered as many questions about how to apply for a SARE grant as I did on specifics for using automated side wall curtains and the varieties of crops we grew.
I have been asked to participate in a live discussion via the internet with UVM Extension Agricultural Engineer Christopher Callahan. Although we set the date more than once the event has yet to take place.
We have shared our SARE grant proposal, application process, experiment set up and results at the 2019 West Virginia Small Farm Conference, during a county wide farm tour, and through one on one visits with local farmers.
At the West Virginia Small Farm Conference I was one of three speakers discussing High Tunnel growing in West Virginia. My presentation was given with the support of a PowerPoint Presentation. I passed out information on SARE grants, literature on the equipment used for the automated side wall curtains, and my farm. The conference room was full to capacity with many of the participants asking questions about my project and specifically on details of side curtain automation, the cost of the automated systems, the timeline for applying for a farmer grant application with SARE, and the specific crops that were grown for the experiment. Even after returning home from the conference I had phone calls and a few emails from farmers around the state asking about year round growing using automated side wall curtains. Based on the number of questions asked I could tell that year round growing utilizing automated side curtains was of interest to those who attended.
On May 14, 2019 we hosted a farm tour and high tunnel workshop. The workshop was advertised by West Virginia University Extension Services with a flier they produced and emailed to high tunnel growers in our area, along with our local extension agent and the county USDA/NRCS office using their email list of growers. We had around fifty visitors in attendance. We shared how to apply for a SARE grant, the timeline for a SARE farmer grant application, specifics about our project, some of the outcomes from our experiment, and then we took a tour of all three high tunnels. WVU passed around a sign in sheet with most of our visitors from local farms. In attendance we had representatives from WVU, our local extension office, USDA/NRCS representatives and a Rimol High Tunnel representative from Ohio.
None of the local growers in attendance currently grew during the winter months in their high tunnels although many were interested. We spent time discussing the three side wall curtain mechanics; the manual roll method, the electric grid automated method and then the solar powered automated method; and the costs of each method. We discussed how to regulate the controls in both automated systems to work based on humidity levels, temperature, and wind. Based on the questions asked most of the growers were very interested in the automated side wall curtains and how this system could benefit year round growing in their high tunnels.
We discussed the three crops I tested; kale, collards, and spinach along with the specific varieties of each crop, the spacing and production outcomes. Many participants were surprised that we were able to successfully grow and sell all three crops throughout the winter months and into early spring. I encouraged all the growers to continue to use their high tunnels throughout the winter months due to local demand for winter greens.
One of the attendees, Karline Jensen, from High Rocks in Hillsboro, WV asked if she could submit a written report from her visit for the Grow Appalachia publication for Berea College.
Karline wrote a wonderful summary of the workshop along with photos taken during the event. Karline also asked if she could bring her students to our farm for a workday/tour in the upcoming year and we have agreed.
Dr. Lewis Jett has also asked if his students may visit our farm this next year for a workday/tour and we are happy to support his efforts.
It is my hope that our project will encourage local growers to extend their growing season and apply for future SARE grants.
Richard and I found that we appreciated and valued the automated sidewall curtains, especially on days when we had to open and close the manual curtains four or five times in a given day due to changes in wind speeds, sunshine, temperature, or humidity. At least six times we had to get up during the night to trek through the snow to close the manually driven sidewall curtains when high winds threatened to damage our crops. There were days when the sun would come out and heat up the high tunnels even though the outside temperatures were in the 20’s and again we would have to trek down to the manually operated high tunnel. The ease of automatically driven sidewall curtains really relieved our stress, saved time, and allowed us to have the freedom to leave the farm without worry. We have already agreed that the time saved along with the reduced anxiety we had with the automated side wall curtains validates our need to automate all high tunnels if we plan to grow crops during the fall, winter and spring months.
The automated sidewall curtains worked as expected and as well as if we had opened and closed manually. Of course the manual operation of the sidewall curtains meant that we had to be home throughout the experimental period which was a struggle especially when we either had company visiting for the holidays or on snowy and windy days. All three high tunnel sidewall curtains posed a problem on days we had significant amounts of snowfall; at that point none of the sidewall curtains worked until the snow was removed manually. Overall we found that the solar powered sidewall curtains worked as well as the direct wired curtains. Both went up and down depending upon the wind, humidity, and temperature.
One of our biggest challenges was collecting temperature and humidity data using the remote bluetooth data logger because of the distance to and from the monitor (in our house) and all three high tunnels. Based on this difficulty we had to manually walk to each tunnel on windy or cloudy days since the transfer of information did not work properly. In the future a higher quality system would be needed to adequately collect this data remotely.
All three crops tested produced as expected. We did learn that planting spinach by seed was a mistake as it took too long to mature. Once the cold weather and short days arrived the spinach went dormant and only became productive once the spring weather arrived. The collard greens went to seed as soon as the weather warmed up, or in early March. Otherwise both the kale and the collards were productive throughout the fall and winter months as expected. All three crops were in high demand and we sold out and wished we had planted more.
At the West Virginia Small Farm Conference I had a lot of questions about the automated sidewall curtains. I believe there is a lot of interest from other growers who want to grow year round and they felt this could help them achieve this goal. When we hosted our farm tour we again had multiple questions and a lot of interest in the automated sidewall curtains. In both situations I asked if any in attendance currently grew crops year round and none had done so prior to me asking. We all could agree that there is a high demand for fresh greens throughout the fall, winter, and spring months. The only negative to using automated sidewall curtains would be the initial cost and the time for installation.