To grow potatoes in straw, place the seed potatoes on top of prepared soil, and cover them with about 4 inches of straw. Add more straw as the potatoes grow to keep the stems covered. Dig through the straw to harvest the potatoes when they are done growing.
Choose a sunny spot for your straw potato garden. Cultivate the soil to loosen it for better growth. Add fertilizer or compost to the soil to provide nutrients for the potatoes.
Use seed potatoes purchased from a nursery or garden store instead of using potatoes from the grocery store, which are often treated to prevent eye growth. Place the prepared seed potatoes 12 inches apart in a row on top of the prepared soil. You don't need to bury the potatoes in the soil. Leave 2 to 3 feet between rows.
Cover the seed potatoes completely with loose, seed-free straw. As the potato plants grow, the stems appear above the straw. When the stems grow to about 4 to 6 inches, cover them with additional straw so only the top inch shows above the straw. Continue adding straw two or three more times. Water the potato plants through the straw as needed if you don't get enough rain.
You can harvest a few potatoes at a time by reaching into the straw to harvest them. Flowers on the plants indicate that small potatoes are growing. To harvest larger potatoes, wait until the plants die off, and move the straw aside.