Common Name: Potato
Botanical Name: Solanum tuberosum
Type and Use: Perennial, grown as an annual for its edible root tuber. All other parts of the plant are toxic.
Location: Full sun
Planting Dates: Many gardeners plant on Washington’s birthday (used to be February 25). Others plant potatoes as early as January. Potato shoots can be frozen back without much damage to the crop. Official planting dates for spring are 2-3 weeks before last frost; for fall, 12-16 weeks before first frost. In general, February 7 - March 15 and July 25 - August 25.
Planting Method: Ruth Stout, gardening author, and many other gardeners recommend planting the entire seed potato. Others like to cut the potatoes into 2-3 ounce pieces about the size of golf balls. Coat the cut surfaces with sulfur or fireplace ashes and allow to callous before planting.
Seed Emergence: Potatoes come up within as quick as a week, but usually 15-20 days when daytime temperatures are between 60-75°.
Harvest Time: 90-120 days
Height: 18-24 inches
Spread: 24-36 inches
Final Spacing: 8-16 inches between pieces in a row and 36 inches between rows
Growth Habits: Leafy vegetables that sometimes flowers in cool weather. The potatoes are tubers and are actually modified stems, not roots. The tubers will tend to swell out of the soil. When they do, the sunlight hits them, they turn green and will give you a tummy ache. Keep them covered with soil or mulch.
Culture: Fertilize fairly heavily when planting rather than doing a lot of sidedressing later. For best production, keep the soil slightly moist. Foliar feed with Garrett Juice at least monthly. For best production, cover potato plantings with a thick layer of natural mulch. Some gardeners recommend "dirting" or piling soil up on the potatoes as they grow. Adding more mulch is better. Potatoes need ample amounts of nitrogen, phosphorus, potassium, and magnesium. They prefer acid soil so add lots of compost and sulfur at 5 lbs. per 1,000 square feet.
Sidedress potatoes about 6 or 7 weeks after planting. The plants should be blooming by this time. Sidedress before hilling (if you choose to do that) so you can cover the fertilizer with soil as you hill. Use half a handful of organic fertilizer per plant or 3 cups per 25 feet of row.
Troubles and Solutions: Control Colorado potato beetles, flea beetles, garden flea hoppers, and aphids with a basic organic program, citrus product sprays, neem sprays, and the release of beneficial insects. Hand pick the first potato beetles to appear. Control nematodes and wireworms (the larvae of click beetles) with citrus pulp and sugar. Root fungi and other soil problems can be controlled with compost, biological products, and cornmeal. Leaf fungi troubles can be controlled with potassium bicarbonate.
Harvest and Storage: Harvest when the foliage starts to turn brown or, even better, just before the foliage starts to turn. Dig and eat as new potatoes as soon as they are large enough. If you get lucky and get a fall crop, cut the tops off after they freeze and leave the potatoes in storage in the ground. How long depends on moisture. If too wet, the tubers will rot. Frozen tubers will rot. Ideal storage temperature is 40°. Potato fruit flowers and sprouts contain toxic substances. Foliage needs to turn completely brown or the potatoes won’t store well. Large-scale farmers don’t wait. They mow the foliage and dig 7-10 days later, which sets the skin so the potatoes don’t rot. Cure potatoes in a dark place above 50° and then store for as long as ½ year at 40-48°.
Notes: The best part of the potato is the skin, but unless you are totally organic, don’t eat the skin. The skin of the potato is the main storage area for pesticides and other contaminants. The same goes for other fruits and vegetables. Fall potato crops are difficult in Texas.
Varieties: White - Kennebec, Red Norland, Red - Pontiac, Red Lasota. Yukon Gold tastes like it is already buttered. Other interesting choices include Yellow Finn, Purple Viking and All Blue. Red potatoes produce better than white ones in Texas.