
A customer sent us a tuber with enlarged eyes and second growths (see picture below) asking what was the cause of these defects. The two articles quoted below indicate excessive rain after a dry spell, or excessive heat.
From the Journal Potato Research
"Summary: The development of potato tubers was observed on plants in which second-growth was experimentally induced by heat treatment. Secondgrowth could be induced by subjecting the whole plant, the underground parts only or the foliage only to high temperature (32°C) for 7 days.
The growth of the primary tubers stopped after the initiation of secondary tubers. This cessation of growth of the primary tuber is not a prerequisite for second-growth, but results from the dominance of the secondary tuber.
Depending on which part of the plant was subjected to heat, different forms of secondgrowth occurred such as elongated tubers, bottlenecks and chain-tuberization. It is supposed that the origin of these forms depends on the strength of the elongating influence. This strength manifests itself in the time of occurrence of sprouts and in their number and length.
Observations on the induction of second-growth in potato tubers"
Journal Potato Research
Publisher Springer Netherlands
ISSN 0014-3065 (Print) 1871-4528 (Online)
Issue Volume 7, Number 4 / December, 1964
DOI 10.1007/BF02368253
Pages 219-227
Subject Collection Biomedical and Life Sciences
SpringerLink Date Thursday, April 13, 2006
Secondary growths
From an internet article by the Potato Council: Supporting the British Potato Industry
"The symptoms are excessive protuberances at the eyes. There may also be a development of small chain tubers attached by a length of stolon. Others may elongate, producing a dolly effect.
Second growth often occurs during good weather conditions, e.g. wet weather especially following dry conditions.
Control
Control may be partially achieved through the use of irrigation to regulate water supply and by earlier haulm destruction"
http://www.potato.org.uk/department/knowledge_transfer/pests_and_diseases/ref.html?item=48
Q. I own a small farm in Arlington Vermont. The State of Vermont has deemed the soil on the farm to be some of the best in Vermont. My interest would be potato farming. Would 4-6 acres of open field with great soil be enough to be profitable? Your thoughts?
FH
Arlington VT
A. Well, that's a big topic to cover. For starters I'd study Eliot Coleman's “The New Organic Grower” and your fellow Vermonter Richard Wiswall's “The Organic Farmer's Business Handbook.” My advice on farming is to start small, build on success and learn from your mistakes while on the low end of the “J-curve” before education comes at a high cost.
The economics of potatoes as a component of a market operation are very good. Take, for example, the scale of a quarter acre of potatoes. Here are some numbers. At three foot row spacing there are 14520 row feet per acre or 3630' per quarter acre. At 9” in-row spacing that quarter acre would be 4840 hills. At 1.5 ounce seed piece size you'd need 453 pounds of seed potatoes per quarter acre. On the harvest end, assume a reasonable yield of 1 pound per row foot or 3630 pound per acre. Assuming a 90% packout of salable tubers you'll have 3267 pounds of potatoes to sell. In selling if you do a good job with sought after varieties and can average $2/pound in a farmers market setting you'd pull in a gross income of $6534. If you can do the work of growing the crop with your family's labor and keep your out of pocket expenses to under $1500 (20% of gross), you ought to be able to clear $5000 (net) from that little quarter acre. And that's no small potatoes!
One of our growers in Washington state once reported that he planted 750 pounds of our Rose Gold seed potatoes and harvested an amazing 24,000 pounds, a remarkable 32X increase. Most of us won't achieve that kind of success but it's a goal to work towards. Good luck!
Jim
Not long ago we were asked to envision a sustainable food system for Maine. Starting with underlying community values of justice, sustainability, food security and democracy here is our concept of local food sovereignty. While neither exclusive nor complete we believe these are practical goals for our close knit State of Maine. We think they can also be extrapolated to regions with greater populations.
Our Common Values for Maine Food.