The potato, Solanum tuberosum L., is a vegetable in the plant family Solanaceae, which also includes the fruiting crops of tomato, pepper and eggplant. It is classified as a dicotyledonous annual, although it can persist in the field vegetatively (as tubers) from one season to the next.
The edible portion of the potato is a tuber, which is an enlarged portion of an underground branch of a stem called a stolon or rhizome. The potato tuber contains all the characteristics of normal stems, including dormant buds (eyes), rudimentary leaves (eyebrow scars lining the eyes) and lenticels (surface pores). Note that the buds are in a spiral pattern on the tuber and tend to be concentrated at the seed or apical end (opposite end from stem attachment) of the tuber.
Potato propagation is normally by seed piece, planting either a whole small tuber or a piece of a larger tuber containing at least one eye. Vegetative propagation is necessary to assure a very uniform crop for each variety. Although seed pieces provide genetic uniformity, they have the potential of carrying many diseases and thus it is a good practice to always use certified disease-free seed.
There are current attempts to avert this problem by planting seeds from fruits rather than pieces of seed tubers. The rationale for this approach is that very few diseases are transmitted to the next generation when "true" seeds (rather than seed tubers) are planted. The true seeds are planted indoors like tomatoes and transplanted to the garden.
You may enjoy experimenting with this new technique, but there are several problems with it.
- First, the seeds are smaller than tomato seeds, and the seedling plants grow rather slowly at first.
- They are subject to frost and should not be set out any earlier than tomatoes. Plants grown from tubers may also be frosted, but this is usually less serious because the tuber seed pieces will quickly produce new sprouts. Even when plants are not frosted off, the extra food reserves available in a tuber seed piece give a boost to the early plant growth which is not possible from a tiny seed.
- Under the short growing seasons common in the Northeast this early growth is a prime consideration. Yields from true seed will be several weeks later and about 20% lower yielding than yields of similar varieties grown from tubers.
Because potatoes, like other vegetatively propagated crops, do not "breed true", potatoes from seeds have much more variability in plant and tuber characteristics than plants from tubers. This could lead to variable tuber size and shape, cooking quality, disease reaction, maturity, and also color. Except for novelty value, most gardeners will be well advised to plant certified seed tubers rather than true seeds.
Seed of the recommended varieties listed below generally are available and grow well in New York State. Comments following the variety name include scab resistant (R) or moderately resistant (MR), skin color, maturity, tuber size, desirable within row spacing, and other characteristics of interest.
Chieftain: (MR) red, medium early, large tubers, space at 9 inches, has field resistance to late blight,
Katahdin: white, main season, medium-flattened spherical tubers, space at 9 to 10 inches, yields dependably,
susceptible to sunburn.
Kennebec: white, main season, medium to large oblong tubers, space 9 to 10 inches, vigorous grower,
excellent yields, resistant to late blight disease, susceptible to Verticillium.
Norgold Russet: (R) medium early, medium size tubers, oblong to long tuber shape, space at 10 to 12
Norland: (R) red, early, medium size tubers, space at 10 to 11 inches, sprouts early, susceptible to air
Russet Norkotah: (R) new variety, early main season, medium to large long tubers, some tubers
irregular in shape, space at 10 inches, moderately susceptible to Verticillium.
Superior: (R) white, early, medium size tubers, space at 10 to 11 inches, susceptible to Verticillium.
For instance, varieties susceptible to Verticillium may be adversely affected by planting in the same soil where tomatoes, peppers, eggplant or strawberries had been grown a year or two before. Carefully study these characteristics to select varieties in accordance with the climate, practices and disease appearance in your garden.
It is recommended that the garden soil be tested before planting to determine exact nutrient requirements.
Potatoes are less likely to get scabby (a corky, pitted surface lesion caused by a fungus-like soil organism) in acid soils where the pH is between 5.0 and 5.4 since the disease-causing pathogen grows the slowest in this range. In the home garden it is usually not practical to attempt to lower the pH using acid forming fertilizer or sulfur.
Potato yields depend on varieties used, soil moisture, weed competition, and pest damage.
Irrigation increases yields substantially when applied during dry weather. Production in a 10 foot row can vary from 15 lbs. to a full bushel weighing 60 lbs.
As garden sizes decrease, the space consuming potato has been eliminated as popular crop. Because they are available in 60 or 100 lb. amounts at depressed prices in the fall, it is not necessary to home grow storage potatoes to save on the food bill.
On the other hand, it is a fascinating crop to grow, producing its edible portion secretly beneath the soil. Also, some of the best quality, most attractive varieties may not be locally available from commercial sources. And most of all, the taste and quality of fresh-dug potatoes is without equal. Even a small plot of Solanum tuberosum will enhance your garden and your diet.
Resource: Home Gardening Of Potatoes, VC Report 669, by Roger A. Kline and Donald E. Halseth, Department of Vegetable Crops, Cornell University.
Prepared by Thomas Kowalsick, Extension Educator and Dale Moyer, Extension Educator - Vegetable Specialist, Cornell Cooperative Extension -Suffolk County, December 1990.
Revised 12/2006 (TK)