I planted a fair amount of potatoes inside our greenhouse and they seem to be growing well! I was hoping that we could have gotten these potatoes ready in time for Thanksgiving, but so far we have not had such luck. Potatoes are cool weather plants and do well even with light frosts. Even though potatoes grow underground they are not considered roots, but called tubers. You can see in the photographs below the various potato plants that have sprouted.
Potatoes grow well in slightly acidic, loose and well-drained soil. Before planting the tubers, I kept the potatoes inside a box and covered with a brown paper bag. I also placed a ripe banana inside the box to help promote sprouts from the potatoes. Once the potatoes started sprouting, I planted them in the raised gardens. Potatoes form tubers 4-6 in below the surface. When the stem reaches about 8-12 in in height, the soil should be drawn up to cover about half of the lower stems. Our stems are definitely at that height so I needed to add soil to create mounds around the potato stems. I amended a couple bucketfuls of soil with compost and covered half of the stems. We want to keep the tubers from being exposed to sunlight because that will turn the tubers green.
Maximum tuber formation occurs when the soil temperature reached 60-70F. Mulching helps to reduce the temperature, but since I planted the potatoes in early Fall, I don’t think the soil will be too warm. The soil should be kept moist especially when the potatoes are flowering. Potatoes are a vegetable crop that do not require pollination. Below ground vegetables and tubers do not require pollination! This is great for growing inside a greenhouse.
Potatoes can be harvested about 2-3 weeks after the plants flowered. All potatoes should be harvested when the vines die off. Newer potatoes have thin skin and should be handled carefully to prevent bruising. Hopefully, with the addition of amended soil, these potatoes will grow well and we will have a harvest soon!