Tuber production will stop if the temperatures exceed 85 degrees. The potato plant grows initially from the food reserves stored in the tuber. In the Santa Clara valley February 1 through March 31 is the best time to plant. But if cool, wet weather persists, as it did in 1998, it's better to delay the planting until the end of April. If moisture sits on the foliage, fungal diseases can develop.
Potatoes prefer loose, loamy, well-drained soil.
Increasing acidity in our valley's heavy alkaline soil is recommended. Rocky soil and heavy clay can result in a bumpy looking potato. Raised beds that are only 12-15 inches deep work well because potato roots grow wide but not deep. Most roots and all tubers will develop at the same level and above the level that the original seed potato was planted. Use 2-4 oz.