Big Leaves but Small Potatoes?

Question:

My potato plants have huge leaves but only a few small potatoes. What is the problem. We use cow manure for fertilizer.

Hardiness Zone: 6a

Betty from Slate Hill, NY

Answer:

Betty,

There are several factors that can affect tuber growth. The first is harvesting too early. Most potatoes take between 90 and 120 days to fully mature. Once they reach full size, the foliage naturally turns brown and starts to die back. You can harvest them before they mature, but you're going to get smaller potatoes.

Plants usually reach a height of 12 inches and then they go through an enlargement period. During this time, the soil needs to be kept moist (not wet) in order for the potatoes to reach their full size. Over watering can adversely affect their growth.

Another factor that affect their growth is planting non-organic seed using potatoes purchased from the grocery store. These potatoes are often treated with chemicals that inhibit sprouting so they may not grow properly.

In regards to using cow manure for fertilizer, it will work okay as long as it's well rotted. If you use fresh manure, make sure you work it into the soil at least 3 weeks before planting.

Ellen