National Potato Day - August 19

Garden Update

Kathleen Cue, Nebraska Extension Horticulture Educator

In honor of National Potato Day, let’s pay homage to the spud.  Here are some things to know about potatoes and potato plants:

•There are blue, white, and gold-fleshed potatoes, as well as round ones, oblong ones, lumpy ones, and fingerlings. Skin colors are red, russet, blue, and golden.

•Seed potatoes should be certified disease-free to prevent transfer of diseases to new crops and contaminating the soil.  Late blight, Phytopthora infestans, will long live in infamy as the pathogen that set into motion the Irish potato famine. The fungal spores of late blight and other pathogens can persist in soil for many years, affecting the health of future potatoes planted there.

•Seed pieces (divided potato sections with at least one eye) can be planted in early spring, 3-5 inches deep. Plants will handle a light frost but not freezing temperatures and extended cold. As plants grow, soil can be mounded up around stems to provide more opportunities for tubers to develop.

•New potatoes can be harvested by carefully pulling away the soil from the potato hill, gently pulling a few potatoes, and then replacing the soil, leaving the plant intact to continue growing.

•Juglone, the naturally occurring herbicide emitted by black walnut trees, is highly toxic to potato plants and will cause wilt. Plant potatoes well away from any black walnut trees.

•Flea beetles and leafhoppers feed on potato foliage but the most voracious eater, the Colorado potato beetle, can be the toughest to manage. The CPB has developed resistance to many of the insecticides used to manage their numbers.  In a home garden, pluck beetles and their spongy offspring and drop them into a bucket of soapy water.

•Some potato varieties flower and set fruit atop plants. The green fruit is about the size of a cherry tomato and full of seeds, which do not carry pathogens like the tubers do. Indigenous people saved seeds to start plants the next year when disease problems accumulated in tubers.

•Potato scab is a flaky, crusty abrasion on the skin of the potato itself. While unattractive, it is only cosmetic, and potatoes with scab can be eaten when peeled. Scab tends to develop on potatoes growing in a soil environment with a high organic matter content. 

•Potato tubers are stem tissue and capable of photosynthesis, turning green and producing an alkaloid that is toxic to humans. Keep harvested potatoes out of light and stored in a cool dry place prior to eating them.

•Potatoes and tomatoes are closely related.  Hybridizers have tried crossing these plants in the hope of getting seeds that produce both tubers and tomatoes from the same plant, but, alas, got plants that produced neither. The effort has been successful, however, by grafting a tomato top to a potato root system.

 Photo Below:  Potato Fruit
Potato Fruit

Go to Dodge County Horticulture web page for more gardening information.