Keeping Tubers Buried
Keeping tubers buried is critical for their development. Sometimes new tubers may start growing at the surface of the soil. Exposure to light leads to an undesirable greening of the skin and the development of solanine as protection from the sun’s rays. Solanine is an alkaloid found in potatoes and other Solanaceae family plants. If ingested, solanine can cause poisoning in humans and animals. “Hilling up” or “earthing up”—the piling of additional soil around the base of the plant as it grows—inhibits the development of solanine. An alternative to “earthing up” is covering plants with straw or other mulches.
Blight
While caused by different fungal pathogens, early Blight, and late Blight have the same catastrophic effect on potato plants, and there’s no way to stop it. If you’ve got a blight infection, you’ll see gray-brown spots on the potato leaves that quickly spread, engulfing the leaf with a type of wet rot that causes the leaves to die off. Lesions can also appear on the stems.
Picking off leaves with minimal symptoms can slow the progress of the disease long enough for the potato tubers to swell enough to make them worth harvesting. However, if more than 25 percent of the plant is infected, you should cut it off at the base and burn it or put it out for curbside collection. Whatever you do, don’t compost it!
Once the infected foliage is removed, you can dig up the tubers and use them. Storing tubers from infected plants is not advisable because there’s a good chance they are also infected. They’re perfectly safe to eat but might not keep well and can pass the infection on to other potatoes. So be vigilant and pay close attention to your potato plants.
Here are two videos about Potato Blight that can help you understand what to do if you feel your plants have Blight.
