When is a good time to plant potatos in the Rogue Valley?
Jackson County Oregon
We are happy to hear that you are going to explore the wonderful variety and good taste available to the home potato grower.The rule of thumb is to wait until the last frost date (which for most of the Rogue Valley is the end of April-- remember that is an average last frost date--there could be a surprise in early May some years). If your soil temperature is at least 55 degrees, you can usually safely start the planting a week or two before this date as it takes the potato a little time to sprout. Prewarming the soil by covering it with black plastic can help give you this early start .
You can get an even earlier start if you pre-sprout your potatoes in a warm location such as your home or a heated greenhouse or shed. To presprout potatoes, place them in a pot or box with the ends that contain the cluster of eyes pointing up. Exposing them to light and temperatures of 60 degrees or more will trigger the growth of vigorous shoots, according to David Ronniger, who for years was a major potato producer in Idaho. When you can safely plant the potatoes outside, carefully cut the potato into three or four pieces, each with healthy shoots, and plant into soil of at least 55 degrees. Ronniger recommends foliar feeding the emerging leaves with a liquid kelp or fish based fertilizer. Two more foliar feedings, when plants are 4-6 inches high and again just before bloom should be sufficient. Too much Nitrogen or manure will make all plant and no tubers.Good luck!