February 25, 2018

Construction of the low tunnel system for day-neutral strawberries

Materials needed:

  • Black poly stoppers
  • 3/16 inch stainless steel rods
  • 6 inch Ground anchors
  • Either 4 mil or 6 mil, 12 foot wide clear plastic poly
  • Plastic bailing twine

Once you’ve created your raised bed with drip tape irrigation lines properly installed under the plastic, the next step is to insert the steel rods and black poly stoppers, creating a “covered wagon” look over your raised bed.

To begin your low tunnel construction, cut several 1 inch by 12 inch tubes from black poly.  These will be used as a stopper; you will need two stoppers per rod.

The stainless steel rods should be cut to a length of 10 feet per rod.

Drill a 5/16 inch hole through the center of each stopper.  The stoppers will need to insert tightly into the 3/16 steel rods.  Install the stoppers onto the steel rods, prior to installation, one at either end as seen in the picture below. 

Steel rod supports

Prior to covering with clear plastic, each raised bed row should be prepped with steel rods and black poly stoppers

Once your rods have been cut to length, and there are two stoppers on each rod, insert the rods at an angle into the ground, inserting approximately a foot and a half of the rod into the ground on either side of the raised bed.  The stoppers should rest on top of the soil.  The hoop should be 2 feet above the raised bed.  Continue inserting rods down the length of your raised bed, placing one every 5 feet.   

Steel rod supports

Insertion of the steel rod supports down the length of the raised bed.

Now that the steel rod supports are placed over the entire length of your raised bed, you will need to put in a ground anchor at each end of your raised bed.  Each row will need two anchors.

Ground anchor

Insert the ground anchor at an angle, one at each end of the raised bed

 Now you are ready to install the clear plastic poly over the top of your steel rod supports.  You will need a 12 feet wide,  4 or 6 mil clear plastic poly covering. Begin by putting the plastic over the hoops; this will take several people to hold in place.

Step 1:

Unroll clear plastic poly over the top of the steel hoops. 

Plastic covering

Unrolling plastic over the top of the hoops.

Step 2:

Gather the plastic at the end of the bed and hold tightly while securely tying

Anchoring the ends

Gathering plastic at the end of the row and tying with rope.

Step 3:

Fold up the end of the plastic back onto itself and continue securing with rope. Then tie the end of that rope to a spring tensioner. Leave adequate amount of excess rope between the plastic and the tensioner to work properly. 

Anchoring

Doubling over the plastic and tying the rope to the spring tensioner.

Step 4:

While the plastic is held down, fasten the spring tensioner to the ground anchor previously installed. Leave an adequate amount of rope between the tensioner and the ground anchor. 

Anchoring

Securing the spring tensioner to the ground anchor.

Repeat this process of securely tying the plastic on the other end of your raised bed.  Once the plastic is securely tied to both ground anchors, you can begin the process of rolling up the excess plastic on both sides of the raised bed.

The best method for rolling up the plastic is to have two people on each side, rolling up one 5-foot section at a time. Roll the plastic up so it is approximately 20 inches off the ground. To hold this position, the black stopper is moved up on the steel rod to hold the plastic in place. 

Rolling plastic

Rolling up the plastic.

Continue rolling up the plastic in 5 foot sections until you’ve completed the row.  Now the stoppers need to be secured and the plastic needs to be tied down using plastic bailing twine.

Step 1:

Using black electrical tape, secure the stopper by placing the tape above and below the stopper to secure it onto the rod.   This will help to secure the stopper, keeping the twine tight on the plastic to help hold in place in the event of high winds.

Securing stoppers

Securing the stopper with electrical tape.

Step 2:

With the bailing twine, you need to loop the twine around one of the stoppers with equal lengths of twine in your right and left hands. Wrap twice around one of the stoppers, then bring the twine over the top of the plastic so that there is twine on either side of the steel hoop.

Looping twine around stopper.

Looping twine around the stopper.

 Step 3:

With the middle of the twine secured on the one stopper, and brought over the steel hoop, you will now have the two loose ends of twine to secure at the other stopper.

Securing the plastic

Securing the twine to the opposite stopper.

Step 4:

Wrap the twine around the stopper twice and tie off using a secure knot. 

Securing the plastic

Tying off the twine.

Step 5:

Using a separate piece of twine, secure the twine that is on either side of the steel rods by tying it to the adjacent twine.

Supporting the hoops

Secure twine that crosses over the plastic.

Step 6:

For added support on the ends of your rows, go to the halfway point from where the plastic is tied onto itself and to the first hoop. Pick up the bulk of plastic and roll together, securely tying with twine. As an added measure, tie another piece of twine from the first hoop down to the twine you just secured. On the underside of the plastic, tie twine to the steel hoop, and secure to the halfway point twine.

Securing the ends

Adding support with extra twine.

After you’ve completed these steps for each row, your low tunnel system is ready for strawberry production.