Consider planting potatoes
Advice to Grow By, The Press Democrat
Sonoma County Master Gardeners
Contributors to this column: Janet Bair, Kim Roberts and Debbie Westrick
Have limited space in your garden? Consider planting potatoes
Answer: Yes! Potatoes are well-suited for growing in containers. One option is a grow bag, a fabric pot that is easy to move for optimal sun. The porous fabric allows the bag to breathe, which can prevent overheating and overwatering. March is an ideal month to plant potatoes; for a continuous harvest, you can plant them every month from March to August.
Buy seed potatoes from a nursery that displays a Certified Seed Potato tag, to ensure they are free of disease. Avoid grocery store potatoes; often they are treated with sprout inhibitor.
If you are new to potato cultivation, try a variety recommended on our Master Gardener website: ‘White Rose’ (high-yield, large; white waxy flesh with moist texture), Kennebec (high-yield, white flesh, stores well), ‘Norgold Russet’ (medium-yield, white flesh), ‘Red Lasoda’ (red skin, white flesh, stores well) and ‘Yukon Gold’ (gold flesh with dry texture).
If your seed potatoes are small, you can plant them whole. Cut larger seed potatoes into pieces weighing 1½ to 2 ounces. Make sure each piece has at least one eye. Then store the freshly cut pieces at room temperature for one to three days to allow the cut surfaces to dry and form a callus, which decreases rotting.
Potatoes grow best in well-drained, loose soil. A good potting soil or a mix of soil and compost works well. Add about 3 to 4 inches of soil to the bottom of each grow bag. Place four to six small or cut seed potatoes onto the soil. Then cover them with an additional 3 to 4 inches of soil.
When the plants reach about 4 inches tall, add more soil to cover. This is called “hilling” or “dirting.” Continue hilling as the plants grow until the bag is full. By covering the base of the plants as they grow, you prevent the potatoes from getting too much sun exposure, which can cause greening, a toxic condition.
Soil in a grow bag or container can dry out quickly. Regularly monitor the moisture content of the soil; it should feel moist, but not soggy. In the hottest part of the summer, you may have to water every day. Note that excessive watering may cause rotting. If the soil is alternately wet and dry, the potatoes may become rough and knobby.
Monitor your plants for pests such as the flea beetle and aphids. Hose off aphids with water or spray with an organic insecticidal soap. Here is a good reference on pest identification and control.
Harvest your potatoes when their vines die, in late July or August, or approximately 90 to 120 days after planting. Carefully empty the bag, plants and soil to unearth your potato bounty. Brush off most of the soil, then store the potatoes in a cool, dark place.