Buying guide
Where to Buy Seed Potatoes
The best place to buy seed potatoes is a garden center, farm store or seed catalog that sells certified seed. Certified seed potatoes are inspected for disease and aren't treated to stop sprouting, which makes them the safest start for a Kratky container. This guide covers where to buy, when to order and what to check when they arrive.
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What certified seed potatoes are
Certified seed potatoes are grown under a seed certification program, run by state or provincial agencies in the main seed potato growing regions. The crop is inspected in the field and in storage for diseases and viruses, and only lots that pass are sold as certified, usually with a tag or label to show it. Seed potatoes are ordinary potato tubers. "Seed" means they're grown and sold for planting, not that they're true seeds.
Where to buy seed potatoes
- Garden centers and farm or feed stores sell seed potatoes in season, often by the pound, and let you pick firm tubers yourself. The choice of varieties is usually limited to a few common ones.
- Seed catalogs and specialty potato growers offer the widest choice, including fingerlings and blue or purple varieties. They usually ship close to planting time for your area.
- Online marketplaces, including Amazon, are convenient. Check that the listing says the seed is certified, when it ships, and what other buyers say about the condition it arrives in.
Where not to buy them
Potatoes from the grocery store are sold for eating, not planting. Some are treated to stop sprouting, and none are inspected for disease the way certified seed is. Saving your own potatoes to replant works for a season or two, but diseases can carry over from one crop to the next, so most growers start each season with fresh certified seed.
When to order
Seed potatoes are sold from late winter into spring. Popular varieties sell out, so order early, and let mail-order sellers ship at the right time for your area rather than storing the potatoes for weeks yourself. Outdoors, potatoes go in early in spring so they finish before summer heat, so time the order to arrive a few weeks before you plan to plant. If you grow indoors under a light, you can plant at any time of year, but you'll still need to buy while seed potatoes are in season.
How many to buy
Plan on one plant per container, which means one small seed potato or one cut piece per container. Buy a few extra to allow for any that don't sprout. Seed potatoes are often sold by the pound, and a pound of small tubers usually covers several containers, depending on their size.
What to check when they arrive
- Firm tubers with plenty of eyes.
- No soft spots, mold or rotten smell.
- Short sprouts are fine, and even a good sign. Long, pale sprouts are fragile, so handle them gently.
- Unpack them right away. Don't leave them in a sealed bag.
Sort them as soon as they arrive. Set aside the firmest tubers with the most eyes for planting, and throw away any with rot so it doesn't spread to the rest.
Until you're ready to chit them, keep seed potatoes somewhere cool, dark and dry. A few weeks before planting, bring them into a bright, cool spot so they grow short, sturdy shoots, then follow step 1 of how to grow potatoes without soil.
Choosing a variety
For a first Kratky container, choose an early variety with a compact plant, such as Yukon Gold or Red Norland. See potato varieties for Kratky growing for how to match a variety to your container, and the full list of Kratky potato supplies for everything else you'll need.
Questions about buying seed potatoes
What does certified seed potato mean?
The crop was grown under a state or provincial seed certification program and inspected in the field and in storage for diseases and viruses. Only lots that pass are sold as certified, usually with a tag or label.
Are seed potatoes the same as potato seeds?
No. Seed potatoes are tubers grown for planting. True potato seed comes from the small berries some potato plants make, and home growers rarely use it.
How long can I keep seed potatoes before planting?
A few weeks somewhere cool, dark and dry is fine. Kept warm for long, they grow long, weak sprouts and start to shrivel.
How many seed potatoes do I need?
One small seed potato or one cut piece per container, plus a few extras in case some don't sprout.
Should I cut large seed potatoes?
You can. Cut them into pieces about 1¼ inches across, each with at least one eye, and let the cut faces dry for a few days before planting.
Related Kratky potato guides
More on growing potatoes with the Kratky method, from the first sprout to the harvest.