phytophthora infestans

Potatoes at the grocery store look good in their clean display case, which makes you want to buy them. However, their clean appearance can make it more difficult to use them for growing new potato plants. So, can you grow potatoes from store bought potatoes? You can grow potatoes from store bought potatoes, but they are often treated with clorproham (an herbicide/sprout inhibitor). Potatoes without sprouts are more attractive on store shelves. However, treated potatoes take longer to sprout, and the resulting plants may show stunted growth. Of course, you can try to wash off clorproham from store bought potatoes to make it easier to sprout them and grow new plants. However, this might not work – and even if it does, it brings another set of risks to your potato plants. In this article, we’ll talk about growing potatoes from store bought potatoes and what to look out for. We’ll also take a look at ways to sprout potatoes faster, no matter where they come from. Let’s get started. Can You Grow Potatoes From Store Bought Potatoes? You can grow potatoes from store bought potatoes – I have done it in the past, and it does work. However, there are some reasons to avoid doing this: Use of sprout inhibitors – many store-bought potatoes are grown in large-scale commercial farming operations, which use sprout inhibitors so that potatoes remain saleable for a longer time period.Risk of disease – this is possible even for organic potatoes. Planting diseased potatoes can pose a risk to neighboring plants, especially other members of the nightshade family (such as tomatoes). You can grow potatoes from store bought potatoes, but there are some reasons to avoid doing so. Let’s examine these risks in a little more detail. Sprout Inhibitors For Potatoes When potatoes are not treated to prevent sprouting, they won’t last as long on stores shelves. This leads to more food waste for grocery stores and higher prices for shoppers. Potatoes that are not treated will sprout much faster than treated ones. Clorproham is an herbicide and sprout inhibitor that is often used to treat potatoes. When potatoes take longer to sprout, they have a longer shelf life at the grocery store and in your home. For these reasons, sprout inhibitors are not all bad. However, they do cause a problem if you want to grow new potato plants from old potatoes that have sprouted on your shelves. Potato plants treated with clorproham will take longer to sprout, even in ideal conditions. This makes it a little more difficult to plan ahead for when to purchase store bought potatoes for planting. Even after store bought potatoes begin to sprout, the clorproham is still present on the potatoes. Since it is an herbicide and sprout inhibitor, the clorproham will continue to prevent sprouting and growth. This will hold back development of the new potato plant. In my experience, seed potato plants grow larger and healthier than potato plants grown from store bought potatoes. Don’t get me wrong - potatoes grown from store bought ones can still do well, and ours certainly did. Clorproham will delay sprouting and can stunt growth of potato plants. However, seed potatoes are produced specifically to grow new plants, and they are not treated with sprout inhibitors that could stunt their growth. Of course, you can always try to wash clorproham off of potatoes before you try sprouting them or planting them. However, you might not be able to get all of it off with a simple washing. Besides, getting potatoes wet can also increase the chance of rotting or disease. Speaking of potato diseases, there are a couple that we should mention now. Potato Diseases If you buy organically grown potatoes, it is likely that they won’t have sprout inhibitors on them. However, any store bought potatoes can carry and spread disease, whether they are organic or not. Blight is a common potato disease, and there are two different types: early blight and late blight. Early Blight Of Potato Early blight is a disease caused by the fungus Alternaria solani. It affects potatoes, but it can also affect tomatoes. Early blight can also affect tomato plants. Early blight can damage the leaves, stems, and tubers of potato plants. The fungus that causes early blight can spread by: Spores on the windHuman contactWater splashing infected soil onto lower leaves of plants Early blight can spread to multiple potato plants (or all of your plants) from a single infected tuber that you planted. If potato plants are close together, early blight can spread between them. Early blight it the less deadly of the two types of blight. However, it is still a garden nuisance to avoid if possible. If possible, choose potatoes that are resistant to blight when planting. Late Blight Of Potato Late blight is caused by the water mold Phytophthora infestans. It affects potatoes, but it can also affect tomatoes. Late blight can affect the tubers, leaves, and stems of potato plants. It can also spread to destroy an entire crop of potatoes or tomatoes. Late blight favors wet, cool climates and it can damage the leaves, stems, and tubers of potato plants. The fungus that causes late blight can spread by: Spores on the windSurviving the winter in infected potato tubers (even those left underground) Late blight it much more deadly than early blight. It can destroy your entire potato or tomato crop. In fact, late blight caused the Irish Potato Famine in the 1840’s. This disease should be avoided at all costs. Choose late-blight resistant potatoes for planting, and buy certified seed potatoes to help prevent this disease. You can find certified disease-free seed potatoes from reputable seed and plant companies such as: Fedco SeedsGurney'sJohnny's Selected SeedsHigh Mowing Organic Seeds (If you are also growing tomatoes, opt for blight-resistant tomato varieties, since both types of blight can spread between potatoes and tomatoes). Can Regular Potatoes Be Used As Seed Potatoes? Regular potatoes (store bought potatoes) are not the same as seed potatoes. Regular store bought potatoes are grown for eating – they are not intended for planting, although it is possible to plant them. You can still get healthy plants from store bought potatoes. This potato plant in a container grew quite well last year! Seed potatoes are bred specifically for growing new potato plants. They are certified disease-free so that you don’t have to worry about spreading potato diseases like blight in your garden. In addition, seed potatoes are not treated with clorproham. As a result, there is no herbicide/sprout inhibitor to stunt the growth of a potato plant grown from a seed potato. The table below summarizes the differences between store bought and certified seed potatoes in terms of their purpose, likelihood of disease, and treatment with herbicides or sprout inhibitors. PotatoesStoreBoughtPotatoesCertifiedSeedPotatoesPurposeGrown for eating.Bred for sprouting to produce new potato plants.DiseaseMay carry diseases, such as early blight or late blight.Certified disease free when purchased from reputable companies.TreatmentOften treated with herbicides or sprout inhibitors, such as clorproham (esp.if not organic).Never treated with herbicides or sprout inhibitors.This table summarizes the differences between store bought and certified seed potatoes in terms of their purpose, likelihood of disease, and treatment with herbicides or sprout inhibitors. Why Do Potatoes Sprout? Potatoes sprout in order to start the next phase of their life cycle: to produce a new plant. However, they won’t just sprout at any time. Sprouting occurs after a dormancy period, which can vary depending on the type of potato. This happens so that the potato does not begin sprouting at the wrong time (for example, in the middle of winter). A period of dormancy before sprouting protects potato plants from trying to grow during winter. In fact, you can prevent potatoes from sprouting by keeping them at cool temperatures. This will trick them into thinking it is still winter and preventing their natural instinct to sprout and reproduce. A temperature range of 38 to 50 degrees Fahrenheit (3 to 10 degrees Celsius) is ideal for storing potatoes. Keep them at a relative humidity of 90% to 95% to prevent them from drying out and shriveling up. When you want them to sprout, bring your potatoes to room temperature of about 70 degrees Fahrenheit (21 degrees Celsius). They will sprout without soil, but you can also put them on the surface of soil or plant them in a trench or holes about 4 inches deep. If you are ready to grow, take your potatoes out of cold storage and leave them at room temperature to get them to sprout. You can learn more about why potatoes sprout (and how to prevent it or speed it up) in my article here. If you are ready to grow, check out my article on how to plant sprouted potatoes. Conclusion Now you know how to grow potatoes from store bought potatoes. You also know what to look out for and how to make your potatoes sprout faster – no matter where you got them. If you don't have much space for growing potatoes, check out my article on how to grow potatoes in a bucket. I hope you found this article helpful. If so, please share it with someone who can use the information. If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. Enjoy! ~Jonathon