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 grid powered, with a control where the side walls are manually raised 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.
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.
So far we are sharing our outcomes with other growers within our markets. Everyone is excited to for a farm visit to see how the automation works. Plans are for an early spring farm tour coordinated with WVU extension.