Ask the Expert: How Can I Save My Potatoes for Seed?

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All Blue Potato

All Blue has a blue skin and lighter blue interior which lightens more with mashing. Image courtesy of W. Atlee Burpee, Co., all rights reserved and used with permission.

How do I save my potatoes for sprouting next year?”

The potato plant (Solanum tuberosum) that produces the vegetable we love to bake, broil and mash is a cool season crop gardeners often think of as only grown in a farmer’s field.

Anyone can grow potatoes in a backyard landscape, city lot or container garden, too – as long as the soil is fertile and the space sufficient for roots to develop… But what kind of potatoes should you grow, and can you save potatoes from one year to the next?

Can I Grow Potatoes?

Today’s gardeners have before them a wide variety of potatoes from which to choose for growing in their own home garden. You will want to decide which kinds to grow by considering:

•Do I want to store the potatoes for a long time?
• How do I want to cook the potatoes?
• What is the growing season and climate in my area?

From seed to harvest, potatoes take an average of 90 – 100 days, but if you live in an area with a short spring growing season for cool season crops, look for potatoes that produce a harvest in less time. The Ruby Red variety will produce a harvest in 65 days, for instance; in addition it is a long keeper and, for cooks who like color in their dishes, the red skin in potato salad or roasted with other vegetables makes a good summer spud.

Potato Midnight Moon

The potato plant Midnight Moon has a purple skin and can be harvested in 70 days. Image courtesy of W. Atlee Burpee, Co., all rights reserved and used with permission.

Gardeners in North Carolina dig their potato seeds into the soil around late March and take up the majority of the harvest between June and the middle of July. I always recommend checking with your local county university cooperative extension for precise timing and special microclimates; they may know particularities about your region of the state your garden is growing.

Saving Seed Potatoes One Year to the Next

The best seed potatoes for planting are fresh potatoes newly obtained for that purpose, which are USDA certified seed stock. Potatoes are very susceptible to viruses and starting fresh each year ensures the best possible harvest.

If you save potatoes from one growing season to the next to use as seed, keep your potatoes in a cool dark place that is well-ventilated. A root cellar that maintains a temperature of 35 to 40 degrees F is the best example of a good place.

If you want to keep your potatoes for long storage, let them dry out in a protected location away from rain, before you store them.

Potatoes, from one variety to the next, vary as “keepers.” The better keeper varieties will give you more success as a seed potato. The ‘All Blue’ potato is in that category.

Can I Seed with Grocery Store Potatoes?

It is possible to start new potato plants from pieces of cut up potatoes you got from the grocery; in fact it is a fun project for kids. However, for a full serious harvest, grocery store potato pieces are suspect in producing a harvest worthy of your anticipation – much less the time you have put into growing them.

Grocery stores often treat their potatoes with a chemical meant to stifle sprouting. But if you do use a grocery potato; cut up each piece and make sure each one has two eyes.

Seed a Garden with Colorful Spuds and Heirloom Potatoes

Potato plant roots

John Bamberg of University of Wisconsin studying the root system of a potato plant. Image courtesy of USDA-Agricultural Research Service, all rights reserved and used with permission.

The best potato seeds are certified free of disease and are not damaged by bruising. They shouldn’t have cuts in the skin or look dried out.

Obtaining fresh seed potatoes is easy, ensures greater success, and, above all, gives you the opportunity to try several kinds.

The heirloom types are so colorful you will wonder where they have been all your life, but it’s not easy to find them at the local supermarket.

Gardeners find seed potatoes at local garden centers or hardware stores, or by ordering them from a mail-order nursery in late winter or early spring.

Growing Healthy Potato Plants for Successful Harvests

We use similar instructions when we grow a potato seed (a chunk of potato with one or two eyes) whether the variety of potato is labeled from Wisconsin or Idaho, or has red skins or blue insides.

Once you have your seed potatoes, store them in the refrigerator. One to two weeks before your last freeze date, take the seed potatoes out, and set them where they will be exposed to bright light indoors.

Dig deeply, and work the soil with organic material in fall, for planting beds that will be ready in spring. Organic material choices run the spectrum from backyard composted material and farm materials like mushroom compost, to store-bought peat moss or decomposed mature from chickens.

Potato plants

Growing potatoes produces tall leafy plants in the garden. Image courtesy of Holly Baird, all rights reserved and used with permission.

Approximately two to four weeks before your last frost day in spring, plant the seed pieces 4” deep and space them out from each other approximately 12” – 15” inches. Some gardeners plant their potatoes in a more shallow hole, and others experiment with hay bales around the seeds.

For new gardeners, growers in a new climate, or those who have never grown potatoes, use one strategy and adjust to new practices from season to season as your experience lets you feel more confident.

As the potato plant grows, you should mound more and more soil around the stem as it pushes itself outward from the ground. Over many days, as the stem grows six to eight inches tall, you will see leaves appear and eventually you will have small hills of leafy green potato plants dotting your planting bed.

Fertilizing vegetable plants is part of the gardening process. Potato plants are no different. I highly recommend providing an organic food to the plants during the growing season, with a fish meal or similar nutrients, while watering.

Harvesting Potatoes

Potato Kennebec

Kennebec grows potatoes from large plants. Image courtesy of Missouri Botanical Garden, all rights reserved and used with permission.

Gardeners can start to harvest “new” potatoes seven to nine weeks after planting. New potatoes are smaller and sweeter because the vegetable’s sugar has not fully developed into carbohydrates.

Cooks like using the smaller versions for salads because the spuds are better at keeping their form.

But to harvest a full supply, and bigger potatoes, allow the tops of the plants to die back before harvesting.

The best tools to harvest potatoes are simply your hands or a garden fork.

Potato Irish Cobbler

Solanum tuberosum ‘ Irish Cobbler’ is an heirloom variety of potato. Image courtesy of Missouri Botanical Garden, all rights reserved and used with permission.

Potato History and What Bugs this Vegetable

Societies have depended on potatoes for food going back centuries; perhaps even taking the abundance for granted. The potato blight disease played havoc by causing societies life-threatening problems for those who depended, above all else, on this one food source.

In the modern age, gardeners like using floating row cover for discouraging plant pests in a vegetable garden. The light material over a series of hoops is a good tool for discouraging Colorado potato beetle, a main pest of potato plants.

Growing Your Own Potatoes

Harvesting your own potatoes has many rewards; not the least of which is choosing your own varieties and cooking with the freshest potatoes possible.

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