Investigation of increased productivity of a hoop house through better use of space

Final Report for FNE08-632

Project Type: Farmer
Funds awarded in 2008: $3,564.00
Projected End Date: 12/31/2009
Region: Northeast
State: New York
Project Leader:
Kurg Forman
Clear View Farm
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Project Information

Summary:

Note to readers, attached is the complete final report for FNE08-632

Results – We had problems with the SunGro potting soil mix. There was inadequate fertility and water-holding capacity. There were also watering challenges. It was necessary to attend to the gutters constantly while watering to avoid overwatering. Kurt had to install a pressure limiter for the short ten foot lengths of drip tape in each gutter, to avoid blowouts of the end of the drip tape. Managing temperature for cool and warm season crops was a challenge, since we were not very familiar with the daily changes in temperature inside the high tunnel. We used baler twine on some of the gutters which led to eventual fraying and breakage of the twine. Where we used steel cable, there were problems with coming loose on one gutter, when high winds occurred. We installed two deck screws at each end of the gutter to better secure cable to the gutter bottom. We discovered need for a winch, since the gutters were difficult to raise and lower, especially after watering. After installing the winch to raise 3 gutters, we found that the gutters did not raise and lower evenly, perhaps due to uneven weights of each gutter. I believe that additional refinement of the winch system design will alleviate that problem.

Introduction:

The project we conducted looked at increasing the productivity and cost effectiveness of growing more crops using a hoophouse by utilizing the overhead space of the hoophouse. Our investigation looked at using a hanging gutter system to raise selected crops over the existing in-ground crops. We looked at cost effective design, operation, production strategies, cost of production, and profitability of such a system. The space above the in-ground crops is wide open and offers a large potential growing space that could offer greater returns to the operation of the hoophouse. We used aluminum and plastic house gutters and lengthwise split 6” PVC to hold soil medium in which plants could grow, suspended from the high tunnel roof with steel cable or baler twine. Drip tape irrigation was implemented to keep the plants watered. We found that cool-season, shallow-rooted plants worked best in the early spring and late fall, while warm-season, shallow-rooted plants fared well in the warmer part of the growing season. There are advantages to this approach, such as reduced weeding and easier harvest. It does require careful water management to keep the plants happy. We feel this methodology has merit and warrants further research to fine-tune the system.

The farm has not changed except that vegetable acres have increased to about 3 and the percentage of certified ground has increased to about 75%. In addition to the variety of vegetables we grow, we produce field corn, hay, soybeans and small grains. There is a small herd of Angus cattle on the farm that my father owns and sister manages, as well as our small flock of 33 laying hens.
Kurt Forman, Clearview Farm owner-operator, and Robert Hadad, Cornell Cooperative Extension Regional Vegetable Specialist, have designed and built the system; Kurt grows the crops day to day. Robert consulted and scouted plant progress and pests. Kurt and Robert took data on days to harvest, marketable yields, sales, and costs of production and profitability. Both looked at overall design efficiency and updates.

Methodology – Our first step was to design the upper level hoophouse system. We investigated gutter design, the size and number of gutters to implement, suspension options, irrigation, and fertilization techniques – drip tape and fertilizer injection – how to set it all up and rates, how to raise and lower gutters. We decided on a soil type to use in the gutters and the amount (about 1.25 cu. ft.) and the source of soil. I focused on ground cherry production, because putting the plants up in the air would allow me to harvest them in a less difficult manner, by means of collection netting under the plants. We also intended to investigate the merit of growing other crops, like dwarf sugar snap, Asian greens, and lettuce. We used the gutters for early and late-season greens, cilantro, lettuce, and peas, as well as early- main -late season for the ground cherry plants, using at least 5 gutters with 30 plants and compare this with some grown outside. We monitored water usage and fertility, as well as pests and disease. We utilized a trickle irrigation setup and added netting for cukes and ground cherries. We intentionally oriented the gutters in a north-south fashion to help increase sunlight penetration to the crops below.

We added a winch system near the end of the project since it was rather difficult to hoist the gutters up in the air by hand, especially after watering the gutters. We thought that we would possibly need to add hoophouse supports, but the structure I have was plenty rugged enough to support the extra gutter loads. In the future, I plan to exchange baler twine for aircraft cable on all of the gutters, since the plastic twine frayed and broke over time, especially when it was windy. We maintain that cold hardy vegetables, as mentioned earlier, work best early on, followed by warm season crops like cucumbers, then back to cool season crops, is the best approach. We used vegetable-based compost in a soil mixture developed by a local organic grower, which does allow greater moisture-holding capacity and initial fertility.

Results – We had problems with the SunGro potting soil mix. There was inadequate fertility and water-holding capacity. There were also watering challenges. It was necessary to attend to the gutters constantly while watering to avoid overwatering. Kurt had to install a pressure limiter for the short ten foot lengths of drip tape in each gutter, to avoid blowouts of the end of the drip tape. Managing temperature for cool and warm season crops was a challenge, since we were not very familiar with the daily changes in temperature inside the high tunnel. We used baler twine on some of the gutters which led to eventual fraying and breakage of the twine. Where we used steel cable, there were problems with coming loose on one gutter, when high winds occurred. We installed two deck screws at each end of the gutter to better secure cable to the gutter bottom. We discovered need for a winch, since the gutters were difficult to raise and lower, especially after watering. After installing the winch to raise 3 gutters, we found that the gutters did not raise and lower evenly, perhaps due to uneven weights of each gutter. I believe that additional refinement of the winch system design will alleviate that problem.

Ground cherries seemed to need more soil mass and perhaps more fertility, but the small gherkin cucumbers did well. We planted lettuce, cilantro, spinach, peas, and Asian greens. We found that the Dwarf Grey Peas showed potential, while the Oregon Sugar Pod peas were a failure. Some Asian greens did well, while others did poorly. The lettuce and cilantro did reasonably well under cool conditions, but the tendency toward warmer temperatures in the high tunnel, made it more difficult to grow in the summer. Given the low volume of soil used, we found that frequent watering was necessary. The installation of drip tape addressed that problem. We suspected possible pH issues in the potting soil. Given that the soil mix dried out easily, daily attention is needed, especially in the summer. Adding compost and possibly some high-clay soil may help. In the third trial, I used some old barnyard soil, thinking that it would improve water-holding capacity, but the additional weed pressure outweighed any added hydrophilic properties of the soil.
We had trouble with a pinched water line that ran through a culvert across the road between the water supply hydrant and the high tunnel. A piece of steel that acted as a header for the culvert dropped and crushed the water line. Kurt cut out the pinched section and replaced it with a new piece of pipe. A word of caution; some high tunnels may not have the structural strength to support the additional load incurred by a gutter. The size of the gutter can impact how much soil can be contained and the resulting weight on the high tunnel. We put one gutter under each hoop on 14 consecutive of the 25 hoops in the structure. We had no trouble with that arrangement. In some cases, we used some compost with some of the SunGro potting mix, which helped increase water-holding capacity and fertility. This past year, we used different soil mixes and attempted to optimize a recipe for the gutters.

We found that although there was time spent loading the gutters with potting soil and hand seeding, this was offset by less time spent weeding, ease of watering using trickle irrigation and easier harvest. We found that being able to stand while harvesting, generated significant ergonomic benefits and worker satisfaction. Since we came in low on materials expense for the gutters, we decided to carry the project on into another year to fine tune the system, thus adding labor expense. In the end, the project came in close to budget. Yields in the gutters were comparable to crops field grown and in the high tunnel.
We quickly found, once we built the gutters and grew crops, that there was a steep learning curve involved. This year we improved on our growing techniques; for example, we found that putting plants in one row in the gutter yielded bigger, more vigorous crops than double-row seeding. We feel that a larger gutter with more soil volume and water-holding capacity may prove valuable, although weight and size may prove cumbersome. Making this change could mitigate the management intensity needed. One possibility for improving on this would be to cut a narrow slot in the side of a 6” PVC pipe, fill the pipe with potting soil, put spacers in the slot to keep the width of the slot intact, install drip tape and hang the gutter. This would allow more soil volume and reduce evaporation from the soil mix. Different drip tape configurations (flow rate and emitter spacing) may be desirable, as well. There may very well be more opportunity for research to fine tune the system even further.
We have submitted a report to the Kansas City Center for Urban Agriculture and will be having a Cornell Cooperative Extension farm tour in late April or early May to demonstrate the gutters. We will also offer a presentation to the Northeast Organic Farming Association-NY annual conference in January 2011.
List of materials and costs for the gutter system:
14 Gutters (either aluminum (2) or plastic (2) house gutters with endcaps or 6” Schedule 40 PVC pipe (10),
split in half lengthwise with ends duct taped; 2×4’s screwed to bottom of gutters) $ 79.59
Stainless steel cable, clamps, pulleys and wire to tie pulleys to high tunnel frame 86.66
Winch with brake (for safety) 74.85
Irrigation supplies (Drip tape, shutoff valves, braided hose, 3/4” black poly pipe,
barbed fittings, hose clamps) 94.51
1.315” pipe connected between the cables of each gutter and the cable to winch 10.32
TOTAL $345.93
Dimensions of Gutters
6” split PVC: 5.5“ Wide x 120” Long = 660 square inches area (4.58 sq. ft.)
Plastic Rain Gutter: 4“ Wide x 120” Long = 480 square inches area (3.33 sq. ft.)
Aluminum Rain Gutter: 4.5“ Wide x 120” Long = 540 square inches area (3.75 sq. ft.)

Project Objectives:
Methodology

Our first step will be designing the upper level hoophouse system. We shall investigate gutter design, the size and number of gutters to implement, suspension options, irrigation, and fertilization techniques – drip tape and fertilizer injection – how to set it all up and rates, how to raise and lower gutters. We will decide on a soil type to use in the gutters and the amount (about 2.25 cu. ft.) and the source of soil. I wish to focus on ground cherry production, because putting the plants up in the air would allow me to harvest them in a less difficult manner, by means of collection netting under the plants. We also intend to investigate the merit of growing other crops, like dwarf sugar snap, Asian greens, and lettuce. We expect to use the gutters for early and late-season greens, cilantro, lettuce, and peas, as well as early- main -late season for the ground cherry plants, using at least 5 gutters with 30 plants and compare this with some grown outside. We may interplant the ground cherries with lettuce early. We will monitor water usage and fertility, as well as pests and disease management. We will also observe teh effect of the trough system on the plants underneat them.

The gutter system envisioned will be 10 ft lengths of ready-made vinyl rain gutters or plastic pipe wiht end caps. If needed, these will be secured onto 10 ft X 2×4 inch dimensional lumber boards to provide rigidity using wire. Holes will be drilled into the sides of the gutters to allow for drainage. The hoophouse runs east to west so the gutters will be hung north to south. I will plant my high-value market crops of heirloom tomatoes, eggplants, and melons under the gutters. The gutters will be hung suspended from the metal structure of the hoophouse using steel or plastic cable running pulleys to a pipe, which will be moved by a cable attached to a winch, so the gutters can be lowered for easier access.

Cooperators

Click linked name(s) to expand
  • Robert Hadad

Research

Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.