Give the humble potato (Solanum tuberosum) a place in your vegetable garden.
“A nutritional mother lode, potatoes are easy to grow as long as they have full sun, moderate temperatures, and light, rich, acidic, well-drained soil. Try varieties with colors, shapes and flavors you won’t find in the supermarket.” (Cornell University Vegetable Growing guide)
Potatoes are a highly productive crop that frequently yields 10 to 20 lbs. of new potatoes from each pound of seed potatoes planted.
Potatoes may be purchased 2 to 3 weeks ahead of the planned planting date. Use certified (disease free) seed potatoes that are rot (fungus) free and blight resistant (usually available from farm or feed stores or may be ordered online). Some common varieties that grow well in North Texas are Kennebec (white potato), Pontiac (red potato) and Yukon Gold (yellow).
Cutting seed potatoes ahead of planting
Seed potatoes should be cut at least 2 to 3 days before planting to allow scabbing. The scab (suberin coating of cut potatoes) reduces rotting of the seed potato that is sometimes seen when planted immediately after cutting. A bit of powdered sulfur (antifungal) mixed with moist peat moss or saw dust, can be used for longer term storage of the cut potatoes if needed. Stored seed potatoes should be in areas protected from freezing temperatures or high temperatures above 85 degrees Fahrenheit.
Size of Seed Potatoes
Potato pieces of about 2 oz. and 2 to 3 eyes can be cut from large seed potatoes. Small seed potatoes can be left whole or cut once depending on the eyes and weight. Cut large tubers into block‐shaped, 2 to 2 1/2-ounce seed pieces making sure that each piece has 2 to 3 eyes (small indentations in the skin). Cuttings that weigh approximately two ounces are considered best because smaller potato seeds may not have enough energy reserve to support growth. Using potato pieces larger than two ounces offers little benefit. If damaged, suckers will develop in about two weeks on freeze damaged sprouts below the freeze line (damaged area of sprout).
Note: Approximately 3 pounds of seed potatoes are needed for two – fifteen foot rows.
Keep cutting knives disinfected
Using a 5 to 10% bleach solution, rinse and disinfect knives periodically while cutting potatoes reduces transfer from potato to potato of bacterial and fungal contamination.
Soil preparation for home gardeners
Potatoes can be grown in a raised bed home garden, in field rows and in containers. Turn the soil 6 to 8 inches deep with a shovel or rototiller. After leveling the soil with a rake, open shallow trenches 2 to 3 inches deep and 3 to 4 inches wide while spacing rows 3 to 4 feet apart on centers. Lightly scatter a balanced fertilizer (ex. 13-13-13) in the trench and mix the fertilizer into the top inch of soil in the bottom of the trench with a small rake or hoe.
Drop the cut seed potatoes 18 to 24 inches apart in the rows. Using a rake, fill in the trench to ground level. Generously, spread 15-5-10 fertilizer about 18 inches wide across the row. Using a rake or shovel, dig or pull the fertilized soil from the centers between the rows to add an additional 4 to 6 inches of soil directly over the row of potatoes. Potatoes will usually take 3 to 4 weeks to emerge through the soil surface and begin to form leaves.
Timing is crucial for growing potatoes in North Texas. Potatoes are a 100+ day crop for mature, good quality potatoes. The time for planting potatoes starts the last 10 days of February and continues through mid-March. Photosynthesis for sugar to form potatoes needs mildly cool to warm temperatures to grow well. As daytime temperatures reach or exceed 90 degrees Fahrenheit (F) each day (around the first of June in North Texas), most sugar storage stops in potato plants.
Potatoes should be planted 3 to 4 weeks before the average last date for frost. In the Dallas – Fort Worth and Denton areas, the average date for the last frost is the 20th – 25th of March. Since potatoes take 3 to 4 weeks to sprout and emerge through the ground, potatoes should be planted between February 20 and March 15 for best results. Potatoes have some sensitivity to frost and will be burned off at the freeze line in the ground with a freeze.
Note: The roots of the potato develop at the seed potato and grow down into the soil benefitting from the balanced fertilizer (13-13-13) that is better for roots. The 15-5-10 will move down into the soil with watering and rain as the potato grows and is better for stem and leaf production. The potatoes are fleshy stems that develop on underground stems extending from the stems below the soil surface but above the seed potato.
Laying By and Side Dressing
Once potato plants reach about 6 to 8 inches above the soil surface, use a rake or hoe to add two or more inches of soil to the row. Fertilizer should be added to the row before pulling dirt to the row to roll in the fertilizer if extra fertilizer/nitrogen is needed – use 15–5–10 for this application.
During potato growth, keep the soil moist but not wet and keep the moisture supply constant. Water the fertilizer into the soil, especially on sandy soils.
When potatoes have bloomed and temperatures are above 90 degrees F. in the daytime (about mid – June) potatoes are ready for harvest. Potatoes are mature for harvest when the potato skin can be rubbed lightly with a thumb or finger and the potato skin does not ‘slip’ or peel. Potatoes should be harvested between the 1st and 3rd week in June. Soils in North Texas are neutral to alkaline and these soils permit fungal growth on the potato (rotting) if conditions are right (heat and wet soil – a soaking rain). Potatoes should not be left in the ground once mature to reduce crop loss.
Note: Moisture stress followed by irrigation or rainfall can cause growth cracks and second growth. If the rainfall is accompanied by hot weather, the rest period of developing tubers can be broken and can cause the tubers to sprout in the soil. Too much water enlarges the pores on the tubers and makes them rot easily in storage (Joseph Masabni, Assistant Professor and Extension Horticulturist, The Texas A&M University System “Easy Gardening Potatoes“).
Field growing potatoes
- Pounds of seed potatoes needed per acre – Calculation: 50 rows – 200 ft. long, spaced at 4 ft. (4 ft. centers) with 18 inch spacing in the row between dropped potatoes, 900 to 1000 lb. of seed potatoes are needed per acre assuming 2 ounce cuttings. For rows on 3 ft. centers you need 1400 lbs. of seed potatoes.
- Soil preparation: The field for planting potatoes should be properly tilled. Soil should be plowed 6 to 8 inches deep to bury weed and grass seed. Disc the plowed ground down thoroughly or rototill the plowed ground. Prepare a field that is well drained and do not plant potatoes in low places where water will stand. Wet soggy ground will rot the seed potatoes.
- Row preparation: Using a row splitter, open up furrows about 5 inches deep. Put fertilizer in the row, and re – furrow or cover the fertilizer about 1 in deep. Drop the cut seed potatoes about 18 inches apart in the row. Using a row former to cover the potatoes 4 to 5 inches deep.
- Fertilizer: Usually 120 lbs. of nitrogen per acre. Fertilizer can be put in the row (rows at 4 ft. spacing) or half in the row and half added later as side dressing. This requires 16–50 lb. bags of 15-5-10/acre.
- Laying by: As potato plants reach 6 to 8 inches above the soil, side dressing can be done with 15-5-10 fertilizer and about 2 more inches of dirt can be pulled up to the growing vines while pulling the fertilizer (side dressing) to the row using a row former.
- Harvest: Using a row splitter, run about 10 inches deep to turnout and expose the potatoes.
Curing and Storing Potatoes
Irish potatoes should be air dried at a temperature of 75 to 85 degrees F. in a dark area with good humidity 75% or greater. This requires about 2 weeks. Potatoes should be stored with some air circulation and kept covered/in the dark. Potatoes will usually keep 3 to 4 months at room temperature (72 degrees F.). To allow proper curing, potatoes need air circulation but no long term exposure to light. Keeping potatoes covered with a cloth towel or hemp cloth allows air circulation but little light exposure.
References and further readings
Home & Garden Information Center, HGIC 1317 Potato, Clemson Cooperative Extension.
Texas Gardener’s Seeds, From our Garden to Yours, Potatoes with a Texas Twist.
HLA 6028 Potato Production, Oklahoma Cooperative Extension Service, Oklahoma State University http://dasnr22.dasnr.okstate.edu/docushare/dsweb/Get/Document-1127/HLA-6035web2012.pdf
Commercial Potato Production in North America, The Potato Association of America Handbook
Guest contributor: Nat Mills Ph.D., is a Professor in the Department of Biology at Texas Woman’s University. He grew up on a farm in South Central Kentucky where the family raised several garden vegetables each year. He obtained a B.S. degree from Western Kentucky University with a major in chemistry and a major in Biology. He earned his Ph.D. in Human Medical Physiology at Vanderbilt University. He did postdoctoral training at the Pennsylvania State Medical Center in Hershey where he and his wife had plots in the Hershey community gardens. He worked for 7 years at Case Western Reserve University – University Hospitals, in Cleveland Ohio, where he and his wife gardened in the University community gardens. He has gardened in the Denton Area for 30+ years and the last 7 years being at Shiloh Field community garden Sponsored by Denton Bible Church.