How to Make Grow Tubes
Grow tubes are used often by professional grape growers because they make vine training far simpler, keep weeds away from the plants and keep animals away from the plants while they're young. They can also help the vines grow thicker and stronger than vines grown without these tubes. While there are a variety of commercial options, you could also make your own fairly easily.
Measure and mark the growing tube's dimensions. Make the tube 12-inches wide, and the height needed for your plants. Commercial tubes come in 6-inch intervals from 1-foot to 5-feet tall. The recommended height is 6-inches lower than the height of your cordon wire.
Cut your tube out of the plastic sheet.
Punch holes along the left and right side of the sheet at regular intervals, making sure that these holes line up on either side. Space them about 2-inches apart, and start from the top on both sides.
Repeat Steps 1 through 3 for any more tubes you wish to make. If you have not already planted your grape vines, do so now.
Roll the tube around the vine below the cordon wire. Make sure the holes on either side line up. Make sure you don't crease or fold the tube, Take care to preserve a circular shape—flat edges will absorb too much light and heat, damaging the plant.
Tie the tube together through the holes with your connectors of choice.
Push the tube slightly into the ground. This will keep the tube from moving around and keep unwanted plants from growing inside the tube.
Repeat Steps 6 and 7 for the remaining grow tubes.
A lot of art and craft stores have corrugated plastic sheets for sale. Remove the tubes before autumn, as the plant should be strong enough to survive on its own by then. Beige or pink plastic is ideal, because it reflects the right amount of light for the grapes.