Homeowner Forum / Lawn and Garden / January 2007

This is what I found>>
Potatoes  Watering and care
For the maximum crop, keep your potato vines well watered throughout the
summer, but especially during the period when they are in flower, and
immediately thereafter. This is the time when the plant is creating the
new tubers, and water is critical. Water early in the day so that the
foliage has time to dry completely before evening. (Wet foliage can make
your plants more susceptible to several potato diseases.) When foliage
turns yellow and dies back, discontinue watering to allow the tubers to
"mature" for a week or two before harvesting.
Once the vines have passed the critical watering stage while in flower,
they will tolerate a certain amount of drought. According to some
studies, non-irrigated potatoes are less watery and more healthful.
However, potato plants which are not watered regularly will produce a
much smaller crop.
The Potato Harvest
Your may begin to harvest your potatoes 2 to 3-weeks after the plants
have finished flowering. At this time you will only find small "baby"
potatoes if you were to dig up a plant. Potatoes can be harvested any
time after this, by gently loosening the soil, reaching under the plant,
and removing the largest tubers, leaving the smaller ones to continue
growing.
If you want late potatoes for storage, wait 2-3 weeks after the foliage
dies back. Carefully begin digging a foot or so outside of the row or
mound. Remove the potatoes as you find them. (Be careful not to bruise
or cut the tubers with your spade!) If the weather is dry, allow the
potatoes to lay on the soil surface, unwashed, for 2-3 days so they can
dry. If the weather is wet, or rain is expected, move the harvest to a
cool, dry area (like a garage or basement) for the drying period. This
drying step is necessary to mature the potato skin, which will protect
the potato during storage.
If, by the end of September, the plants have not begun to die back, all
of the foliage should be cut off to ensure your crop has ample time to
mature before winter.
Store your undamaged potatoes in a well-ventilated, dark, cool (about 40
degrees) location. Properly dried and stored potatoes should keep well
for three to six months.

Don't grow potatoes in the same soil more than once in three years. Many
diseases and insect pests will survive and remain in this area, in spite
of your best eradication efforts!

Best of luck