Why Grow Vertically?
What makes potatoes unique is that they form tubers along the portions of the stem that grow underground. More room for underground stems means more tubers will form along the stem. These tubers may not be as large as those grown in the usual fashion, but overall productivity in terms of the weight of the crop is often comparable.
The Potato Box
A potato box is pretty much what it sounds like – a series of wooden frames that can be stacked one on top of the other. No formal plans are necessary. As the potatoes in the box grow taller, additional frames are added and the above-ground portions of the potato plant are covered with more soil. Tubers will form along the buried portions of stems.
Building a Potato Box
Choose water-resistant wood such as cedar. Although any screws will work, brass screws are more rust-resistant. To build a box, you’ll need:
- Untreated wood boards – six 2”X6” boards each eight feet long.
- Untreated wood studs – two 2”X2” studs each six feet long.
- A one-pound box of 2 ½” deck screws.
- Drill and drill bits.
Cut the studs into four pieces 33 inches long. Cut the boards into 12 lengths of 21 inches and 12 lengths of 24 inches. Pre-drill holes to make it easy to remove screws. Screw two 21-inch and two 24-inch board lengths to together to form a rectangle. Repeat to make a total of six rectangular frames. Place one 2”x2” stud on the inside of each corner and screw into place.
Set-up and Planting.
Place the first frame on the ground or wherever you plan to grow your potatoes. Make sure it’s in full sun. Slide a second frame over the studs. Fill the box with soil. You can use commercial potting soil or mix your own. Soil should drain well, have lots of humus and be slightly acidic and high in fertility. Plant your seed potatoes about three inches deep and cover with soil.
Growing On and Harvesting
As your potatoes grow, add another frame each time the above-ground growth is a foot high. Cover one-third of the plant with soil. Keep your plants well-watered until the tops start to die down, then stop watering. Harvest potatoes by removing the lowest board on the frame. Remove potatoes, replace the frame and repeat the process every two weeks. Or simply turn the box on its side and harvest the entire crop.