

So, off I went to the big box store and picked up some more potting soil. 2-1/2 cubic feet later, I had gingerly added more soil to the top leaves of the potato plants. I'll add some more soil when the top grows more, but I can't anticipate them getting much bigger. Deeper soil layers helps keep the potatoes from becoming green, which you want to avoid since that's a sign that the tuber could be producing the nasty, toxic alkaline solanine, as potatoes are in the nightshade family. All parts of a potato plant are toxic except for the tuber.
The potato geek taxonomists have divided potato growth into five stages. Stage one involves sprouting and root growth. During stage two, the potato starts forming leaves and branches for photosynthesis. In the third stage, stolons develop out of leaf axils (nodes) on the stems and grow downwards for new tuber development as swellings on the stolon. If the weather gets much hotter than 81 degrees F., tuber formation often halts. The tuber formation bulks up during stage four, when the plant invests a lot of its resources into this process. At this stage it's critical to keep optimal soil temperature, nutrient availability and balance and pests control a top priority. The last stage is maturation where the plant canopy dies back and the skins on the tubers harden. This is when sugars convert to starches.
To harvest, I'll wait until after bloom and when the foliage starts to die back. All I'll have to do is dump the can onto a tarp and pick out the potatoes. I'll put the soil back in the can and put the lid on to store over winter. Next year, I'm getting several more cans so I can produce more varieties. I'll try stretching the soil with compost. Upon harvesting, potatoes need a curing time, but I'll write about that at that time.