A Texan who loves potatoes has discovered a few things that will improve the spud harvest for anyone across the South, and maybe for northerners, too. Here's what Jerry Holmes, a master gardener and NG member who lives about 100 miles northeast of Dallas, says to do.
Jerry gardens in USDA Hardiness zone 8, with a frost-free season that extends from April 3rd through November 18th most years. He produces between 500 and 600 pounds of potatoes a year, in three 250-foot rows.
He says plant 'Viking Purple' or 'Yukon Gold'. These are by far the best keepers Holmes has discovered over many years, trialing 10 to 12 varieties each year. Both will last right through the following winter. The varieties 'Caribe' and 'Yellow Finn' are nearly as good, he has found. You'll probably have to order these varieties from mail-order suppliers.
Avoid the standard 'Norlands', 'Kennebecs', 'LaSotas' and 'Pontiacs' that are commonly sold at garden centers and seed stores. The problem with those varieties in the South is that they lose their ability to keep when they develop in the heat that comes as the potatoes mature. They make nice "new" potatoes, but the crop begins to spoil within two weeks of harvest, Holmes told me.
Another perhaps slight advantage with 'Viking Purple' is that Colorado potato beetles seem to avoid it, at least when they have other potatoes to turn to. The first three years Holmes grew it, 'Viking Purple' had absolutely no beetles, while adjacent varieties had plenty. The last two seasons he has found a few beetles in his section of 'Viking Purple', which suggests that if grown alone, the beetles would feed on it.
Pinch off flower clusters and watch yields increase by 15 to 20 percent. Holmes tested this practice for five seasons. He began removing the blossom clusters as soon as they appeared on half the plants of a given variety. He would do this every few days, as he patrolled for beetles. On varieties that flowered heavily (not all varieties flower consistently from year to year, he has found), the yield advantage varied from 13 to 19 percent. Holmes recorded the number of tubers, the average weight and the weight of the five largest. Most of the increase is due, he learned, to the individual tubers becoming larger, which is a nice feature indeed.