PG: Are some varieties better for storing, eating, baking, or eating immediately?
RH: Potato varieties differ in starch content and this is what makes them appropriate for different uses. Baking potatoes have a high starch content while my Bolivians and fingerling potatoes have a lower starch content, which make them better for boiling. There is nothing better to eat than a "new" potato: one freshly dug or one snuck out from under a growing plant before the main harvest.
PG: What do you advise a grower when looking for a variety?
RH: Consider how you like to cook your potatoes. Many of the garden catalogs that sell potatoes make suggestions for types that are suitable for particular types of cooking.
In addition to starch content, I would consider early, mid and late season potato varieties. My Bolivian potatoes are late season. That means they tie up garden space until frost. You could grow early season potatoes and follow that crop with greens, daikon, or a cool growing crop to get more out of your garden. A first time grower should select any variety that is commonly grown in your part of the country.
PG: Why are sweet potatoes often grown using slips?
RH: I suspect that growing sweet potatoes from slips is a matter of convenience and a way to reduce cost. It is truly amazing how quickly a slip without roots gets established in the garden. Sweet potatoes root along their stems quite easily, and most of the time the slips have roots already started. Sweet potatoes seldom flower at this lattitude so we don't see seed. If you were to grow sweet potatoes from seed you would have a new variety just like you do when you grow potatoes from seed. This happens quite often in tropical lattitudes, which helps account for the large number of commercial varieties available.
PG: What's the difference broadly speaking (I don't want to give away your whole class!) between using potato seeds, seed potatoes, and slips?
RH: When you use seed potatoes or slips you are growing exactly the same plant and genetic material that produced the seed potato or slip. This assures that you are growing exactly the same thing you grew the year before, or that you are growing exactly the variety that you want. When you grow any plant from seed, you are getting a brand new genetic combination that may or may not reflect the characteristics of its parents. This is where new varieties come from. To me, growing things from seed is far more exciting than simply accepting someone else's idea about what I should be growing!
PG: Is there a particular trick to successfully growing potatoes and sweet potatoes? Is there something you do to always ensure success?
RH: Both of these plants (the potato and the sweet potato) are quite tough. If they weren't, they wouldn't be as widely cultivated as they are. Like any garden vegetable, the key to success lies in the quality of the soil in which the plants are grown. All gardeners should be paying attention to developing and maintaining a healthy soil. As long as you do that, you can grow anything.
That said, sweet potatoes and potatoes should not be supplied with extra nitrogen. That will cause both types of plants to produce foliage rather than tubers. Potatoes and sweet potatoes also benefit from mulch. They both like even soil moisture and do not like to dry out until the end of the season.
When harvesting both regular and sweet potatoes take care not to injure the potatoes. Sweet potatoes that have been bruised, scraped, or otherwise injured are more likely to rot in storage. The same is true to a lesser degree with potatoes.
Want to find out more? Check back here for the third and final installment about saving potato seeds, and don't forget to read how it all began. Sign up for Potato Seeds, Seed Potatoes, and Sweet Potato Slips to talk to Royer in person, and take the Project Grow Potato Pledge!
Potato Seeds, Seed Potatoes, and Sweet Potato Slips
Saturday, April 10th
10am - 11:30am
Leslie Science and Nature Center
1831 Traver Road
Ann Arbor, MI