Gothic Tunnel Crossbars

Yes. However, below are some variables to consider, and caution with prudent planning is highly encouraged. These are only our guidelines and not a guarantee. 

Tunnel Orientation

You can install the tunnel perpendicular or parallel to the hillside. It is not recommended to trellis on an installation that is parallel to the hillside with a grade that exceeds three percent. This is due to gravitational pull from the weight of trellised plants on the bottom end of the tunnel. 

With an installation that is perpendicular to the hillside, one could install a basic tunnel with no trellising on up to twenty-five percent grades. 

Prevailing Winds

As far as prevailing winds, an installation of the tunnel parallel to the wind is best. The tunnel will more naturally shed the wind. In a perpendicular installation, in reference to the wind, the side plastic will have a tendency to catch wind and lift. 

This is exacerbated when the tunnel is on a hillside with prevailing winds whipping down the hill side. In this situation, one could still install a tunnel, however, it is recommended to seal off the uphill windward edge by burying the plastic. This will help prevent erosion and water shed inside of the tunnel as well.  See attachment. 

Land Grade

We do not recommend exceeding a twenty-five percent land grade (For Caterpillar tunnels), and no more than 3% (for Guardian and Haven High Tunnels, due to roll up sides and baseboards needing to be very level).  How do you determine your land grade? All you need is a 50” board, level, tape measure, note-taking device. Watch this video to see these tools in action. 

Erosion

The cardinal issue of growing on a hillside is erosion. Contoured rows, terracing, ditching, and raised beds are ways to mitigate erosion. In planning, the grower can incorporate tunnels into their hillside growing. 

In order to execute this, depending on the grade, you will need to cut the lift kit on the high side to compensate for the grade, or remove the lift kit from the high side and combine it with the low side after cutting it to the appropriate length. 

The quick answer: 10–15 feet between tunnels is ideal. At minimum, allow at least one tunnel height, or 8–10 feet. They can be placed closer, but the variables below should factor into that decision.

Orientation and sunlight

Tunnel orientation gets more stress than it deserves. The general consensus — particularly for growers in the northern third of the US — is to run tunnels east-west, but the lay of your land and drainage should take priority over compass direction. If you're on a slope, run your tunnels with the slope rather than across it. My family's farm in Middle Tennessee, Bountiful Blessings Farm, has tunnels facing multiple directions and has never had a production problem attributable to orientation.

For spacing specifically, the concern is shadows cast by a neighboring tunnel. How much that matters depends on your growing season and crop selection — shading is mostly a winter issue, when the sun sits low, and it's less of a factor in the mid-latitudes and South. If you want to dig into this, see Which Direction Should Your Beds and Tunnels Face?

Rain

Tunnels create a watershed for neighboring tunnels and crops, which can cause flooding or seed erosion for direct-seeded crops on outer rows. Soil type, lay of the land, and typical rain intensity all play a role. With soils that absorb water better and areas with less intense rain, tunnels can be placed closer together. Planting a cover crop in between helps with water absorption and weed management.

For example, one customer positioned their tunnels with only a twelve-inch walkway between them and planted a cover crop. This suppressed weeds and increased water absorption, preventing muddy conditions. Shadows weren't a concern given their orientation and crop selection.

Snow

Winter growers need to account for snow. When snow slides off the side of a tunnel, it builds up against the walls. Tunnels placed too close together form a ditch-like pocket where snow collects. Any snow you remove also has to go somewhere. Depending on snowfall amounts and machinery size, count on at least 8–15 feet between tunnels so you can clear snow from the side. The greater the typical snowfall, the greater the distance needed.

You may also find this article on snow useful.

Wind

Wind passing over and around structures can create a wind tunnel effect, increasing wind speeds well in excess of the actual wind speed. Spacing tunnels out or creating windscreens can help.

Receiving large shipments like Caterpillar Tunnels or silage tarps from Farmers Friend is an exciting step for your farm. This guide is designed to help you understand the freight delivery process, what to expect upon arrival, and how to prepare for a smooth and efficient unloading. With the right knowledge and preparation, you’ll be ready to receive your shipment confidently and get back to what you do best—farming.

Delivery Method

Our various Tunnels and other large products are shipped on a 4x8 wooden pallet via motor freight (an 18 wheel tractor trailer). Depending on the order, sometimes multiple tunnels can fit on one pallet. Below is an example of what a past shipment looked like.

Delivery Time

You will receive a pro number for tracking from Farmers Friend when your shipment is picked up from our facility. It is recommended that you contact the carrier prior to delivery to make arrangements for time and date. There is some flexibility in date and time of delivery, but customers in remote areas should accept delivery at the carriers convenience to avoid excessive delays or extra charges. 

Change of Shipping Address

If a change of shipping address needs to be made before your order is picked up from our facility, no problem. However, if this change is made after your order is picked up from Farmers Friend, there will be a reconsignment fee which generally is around $100. Charges are determined by the carrier. 

Verifying Contents

Prior to moving or unloading, please take pictures of the order. This is in case items are missing or damaged we have a way to verify contents and condition. We recommend conducting an inventory of the shipment with your included packing list as soon as possible after unloading.

Unloading

As far as unload­ing, it is the cus­tomer’s respon­si­bil­i­ty. The car­ri­er will not have a fork­lift to unload. A fork­lift or trac­tor with forks works well but is not required, as the ship­ment can be unloaded by hand with two peo­ple. Simply cut and remove any bands or pack­ag­ing. The indi­vid­u­als unload­ing should be capa­ble of team-lift­ing 130 pounds. Out of con­sid­er­a­tion for the car­ri­er, we request you pre­pare to unload as quick­ly as possible.

Farmers Friend does not schedule any shipments with lift­gate ser­vices, and they are not includ­ed in any ship­ping charges, nor is it includ­ed with free ship­ping. If the local ter­mi­nal or dri­ver offers lift gate ser­vices, Please note that there will be an addi­tion­al charge billed to you from Farmers Friend of $150.

Each pallet will not exceed 3000 pounds. Below are some estimated example weights: 

Pallet

• 4'x8' Pallet — 100 lbs

Silage Tarps

• 24' Silage Tarp — 61 lbs
• 32' Silage Tarp — 83 lbs
• 40' Silage Tarp — 99 lbs
• 50' Silage Tarp — 124 lbs

Tunnels

• 14'x50' Caterpillar Tunnel — 350–675 lbs
• 16'x50' Caterpillar Tunnel — 580–650 lbs
• 14'x100' Caterpillar Tunnel — 750–900 lbs
• 16'x100' Caterpillar Tunnel — 950–1100 lbs
• Haven High Tunnel — 700–2750 lbs
• Caterpillar Tunnel Max — 770–2000 lbs

Damage

In the event of your shipment being visibly damaged, we recommend both the driver and you taking pictures. The driver should also note the damage on the Bill of Lading (BOL) and you should send pictures to Farmers Friend. If the damage is excessive (obvious multiple items missing/damaged, pallet has been re-packaged) please refuse the shipment and contact Farmers Friend. We will arrange for a replacement order to be shipped via a different carrier. If there are only a few items damaged/missing, please accept the shipment and Farmers Friend will gladly make arrangements for quick replacement.

What can delay my shipment and/or create extra charges?

Can a truck with a 53’ trailer (semi) safely drive into and out of my area/street/driveway without backing? If a carrier with a large truck can’t navigate the area/driveway there are other options:

• Smaller truck (additional fee applies). Fee is typically $500-$800 above regular shipping charges.
• Deliver to a business in the area that has a dock (reconsignment fee only applies if order is already shipped)
• Deliver to a business in the area that the carrier can safely allow for hand unloading (parking lot, gas station…) (Reconsignment fee only applies if order has already shipped)
• We can set the order for “Will Call” and deliver to a terminal for you to pick up at a scheduled time.

Island deliveries: Many carriers will apply a “Limited Access Fee” to an area that requires a ferry to access or has only 1-2 roads into/out of an area. Other options:

• You can choose to pay the additional cost for your order to be delivered by the carrier.
• We can set the order for “Will Call” and deliver to a terminal for you to pick up at a scheduled time. (Reconsignment fee only applies if order has already shipped)

1. My tractor will only lift _?_ lbs.
   • This could create the need for more than the standard amount of pallets to build the order. This will mean more material, handling, and space on the truck. The fees involved can be discussed with Customer Service as needed.

As always, if you have questions or concerns, please contact Farmers Friend Customer Service at 931-583-0397 or support@farmersfriend.com.

The forecast for wind or snowstorms can give rise to anxiety for many farmers. How do you best prepare for these events? The tips below can assist you in reducing the chance of sustaining damage to your investment. As the elders say, “An ounce of prevention is worth a pound of cure.”

The wind is best prepared for by anchoring, bracing, breaks, orientation, and sealing. In anticipation of a forecasted wind event, loose items should be secured or stowed. Additionally, all hardware and rope or strapping should be inspected to ensure tightness and serviceability.

Anchoring. The most desirable anchoring for tunnels in sustained high wind contexts is either cement or ground anchors. Ideally, ground posts should be anchored on the corners and every other bow. The bows which are not anchored should be driven at least two feet deep. Traditional caterpillar tunnels with rebar should be secured using ground anchors in high wind contexts (see Fig. 1). 

Bracing. Appropriate bracing for high wind includes wind or end wall bracing at each corner and a solid ridge purlin (see Fig. 2a and 2b). Wind bracing and purlin prevents racking of the tunnel from end to end. A lower profile tunnel is better in high winds. The lower profile is one advantage of caterpillar tunnels. 

Breaks. Sustained high winds are the greatest danger to your tunnel. This does not negate the potential risk associated with gusting winds. One way to mitigate both types is by installing windbreaks if natural ones like trees are not present (see Fig. 3). Windbreaks can slow down the wind and offer a protected distance zone ten times its height.

Orientation. Understanding the wind pattern of your farm is important when choosing the orientation of your tunnel. Prevailing winds can be an indicator of how the tunnel should be positioned. However, wind can be unpredictable and orientation rendered useless. The ideal orientation is with the narrow end facing the prevailing wind. This makes the best use of anchoring and bracing while presenting a smaller profile for the wind to catch. 

Sealing. Once you are in an actual wind event all openings should be closed. The side curtains should be dropped and secured with sandbags. If doors have been installed on the ends they should be closed and latched. If the ends are left open for summer ventilation a windbreak should be installed. 

References

Bartok, J. W. (2018, August). Prepare your greenhouse for high winds. Retrieved October 17, 2019, from https://www.greenhousemag.com/article/tech-solutions-prepare-your-greenhouse-for-high-winds/.

Fortier, J.-M. (2014). The market gardener: A successful grower's handbook for small-scale organic farming. New Society Publishers.

Sparks, B. (2016, February 17). Tips to help reduce wind and snow damage at your greenhouse. Retrieved October 17, 2019, from https://www.greenhousegrower.com/technology/tips-to-help-reduce-wind-and-snow-damage-at-your-greenhouse/.

The forecast for wind or snowstorms can give rise to anxiety for many farmers. How do you best prepare for these events? The tips below can assist you in reducing the chance of sustaining damage to your investment. As the elders say, “An ounce of prevention is worth a pound of cure.”

Snow and ice are best dealt with by shape, bracing, spacing, removal, and preparation. In anticipation of a forecasted windy winter event, loose items should be secured or stowed. Additionally, all hardware and rope or strapping should be inspected to ensure tightness and serviceability.

Shape. The best shape for shedding snow is a gothic peak. This is in comparison to a quonset or rounded peak. The steeper angle increases the chances of snow naturally sliding off, and makes it easier to remove the snow that does accumulate. This does not mean that the quonset peak cannot withstand snow loads. It just means that the snow is easier to remove. 

Bracing. Appropriate bracing for snow and ice includes wind or end wall bracing at each corner and a solid ridge purlin (see Fig. 2a and 2b). It is recommended that only one overhead purlin be used, as two purlins create a holding pocket for snow. This increases the weight and likelihood of tunnel collapse or plastic damage. Wind bracing and purlin prevents racking of the tunnel from end to end.

Additionally, if a serious snowstorm is forecasted, one might consider shoring up the tunnel with notched 2x4’s that have 8inch x 8inch feet. For gothic peaks, this bracing should be wedged under the end of truss supports or under the ridge purlin. For quonset peaks, the bracing should be wedged under the purlin or in the center of the bow. It is recommended to place these every other bow or every fourth bow.

Spacing. The NRCS high tunnel initiative CODE 325 recommends that a minimum of ten feet or a recommended twenty feet around the tunnel be clear of obstructions. This is to allow space for snow removal equipment and room for the snow which is removed from the sides of the tunnel. The uneven pressures created by snow buildup on the sides unevenly because of neighboring obstructions or uneven removal from each side is a common reason for tunnel collapse. 

The spacing between neighboring obstructions or tunnels is not the only span to be concerned with. Decreasing the space between each bow (also known as rib or arch) is one way to increase the high tunnel strength. Generally, in areas with snow events, the bows should be spaced four feet apart. 

Removal. The weakest part of the tunnel from end to end is in the middle. This is because there are no end wall braces or anchoring. High tunnels are most stable when there is an even amount of snow build up on each side. Before removing the snow from the top of the tunnel, you should remove it from the sides by shoveling or using a snowblower. 

Snow and ice can be removed from inside the tunnel by bumping the bows or pushing up the plastic. This can be accomplished with a soft bristle broom or a long handle with a tennis ball on the end. Start at the bottom and work your way up. If you start at the top, the snow will have nowhere to go. Doing this from inside the tunnel is preferred as you can alternate from one side to the other easily. 

Sometimes snow cannot be removed from the inside. To remove snow from the outside, tie knots in a rope every couple of feet. Toss the rope over the tunnel and with another person, drag the rope back and forth using the same principles mentioned above. 

Preparation. You will find it prudent to keep a few items on hand. The lumber for bracing to shore up, soft bristle brooms or long handle with a tennis ball, back up poly for covering or patching, and greenhouse repair tape. Also, servicing snow blowing equipment in advance is wise.

References

Growing for Market. (2011, January 20). How to get snow off a hoop house. Retrieved October 25, 2019, from https://www.growingformarket.com/articles/snow-off-hoophouse.

Grubinger, V. (2014, December). Prevent greenhouse collapse. Retrieved October 24, 2019, from https://www.uvm.edu/vtvegandberry/factsheets/PreventGreenhouseCollapse.html.

Lemieux, A. (2011, March 15). Johnny's winter caterpillar tunnel structural trial. Retrieved October 21, 2019, from http://johnnystooldude.blogspot.com/2011/03/winter-caterpillar-tunnel-structural.html.

Natural Resources Conservation Service. (2018, October). High tunnel general specifications. Retrieved October 24, 2019, from https://efotg.sc.egov.usda.gov/references/public/AK/AK_325_High_Tunnel_General_Specifications_Oct2018.pdf.

Poling, B. (2016, January 22). Managing snow and ice with greenhouses and high tunnels. Retrieved October 25, 2019, from https://strawberries.ces.ncsu.edu/2016/01/managing-snow-and-ice-with-high-tunnels-12216/.

Rose of Sharon Homestead. (2019, February 12). High tunnel/greenhouse snow removal & vlog. Retrieved October 25, 2019, from https://www.youtube.com/watch?v=OG82-JokjrU.

Sparks, B. (2016, February 17). Tips to help reduce wind and snow damage at your greenhouse. Retrieved October 17, 2019, from https://www.greenhousegrower.com/technology/tips-to-help-reduce-wind-and-snow-damage-at-your-greenhouse/.

From time to time customers ask about tunnel maintenance in the winter when it is not being used for growing.  This is a great question and the short answer is "it depends on your location and how much you want to work."  Let's explain...

LEAVING THE TUNNEL UP

There are several reasons why leaving a growing tunnel up for the winter could be to your advantage.  The main reason has to do with weather.  If you live in an area that receives a significant amount of snow then leaving your tunnel up allows you to keep the ground relatively prepared for spring seeding and/or planting.  Covered ground is usually not too wet and muddy in spring, requiring less work for  planting.  Because of the shape of the tunnel (usually quonset, rounded) snow does not usually build up excessively since it slides to either side.  If you do leave your growing tunnel up for the winter you also need to winterize the water lines by disconnecting the water source and opening the ends of your irrigation lines to prevent the water from freezing and cracking your lines.  Disconnecting a flush valve, filter and/ or any electronics (like a timer) and storing them inside would also be beneficial to prolong their life.  On the other hand, of you live in a warmer climate that gets little to no snow leaving your tunnel up may work perfectly into your growing strategy as well as not require much extra work.

TAKING YOUR TUNNEL DOWN

If you decide to take your tunnel down for the winter you will incur a little more work, but it may be to your advantage.  The biggest reason to take your plastic off and winterize your water lines would be to prolong the life of your plastic.  By taking the plastic down and storing it inside you remove the weather factor (especially the sun) from deteriorating the plastic and add life to it.  It may be possible to add several more growing seasons by removing the plastic, winterizing the watering lines and storing the flush valve, filter and any electronics.

The down side to removing the plastic, besides the work, would be the shape of the ground when planting season returns.  Again, if you live in a place of significant snow your tunnel may be full of snow in April or even May when you might be ready to plant your cool weather vegetables.  Instead of being covered all winter and ready to plant in spring you now need to clear the snow from your beds which will cause a muddy mess, let it dry and then prepare your beds for planting.  On the other hand, if you live in a warmer climate that does not receive much, if any, snow taking your tunnel down might be a great way to preserve your plastic and increase your investment.

At the end of the day either decision is fine and depends on the amount of work you want to do and the place where you live.  Whether you take your tunnel down or leave it up it would still be good practice to clear your water lines and store any valves, filters or electronics.  Those are relatively easy to detach and reattach when ready.  Happy growing!

See also this video from Curtis Stone from Canada and the amount of snow he sees.