How to Store Seed Potatoes Before Planting?

Properly storing seed potatoes prior to planting is crucial for vigorous growth. Keeping tubers dormant with ideal temperature and humidity controls sprouting and disease. Follow these best practices for storing seed potatoes until your planting date.

Selecting Seed Potatoes for Storage

Start with high quality seed tubers appropriate for your variety and planting time:

• Choose certified disease-free potatoes specifically sold as seed stock.
• Select medium sized tubers between 1.5-3 inches diameter. Avoid very large or small potatoes.
• Pick firm, blemish-free tubers without cuts, bruises or shriveling.
• Handle carefully to avoid damaging flesh or sprouts.
• Use younger seed potatoes, ideally stored less than 1 year.

Getting healthy, robust seed tubers ensures they have ample energy for sprouting and plant growth.

Storing Seed Potatoes by Season

Spring Planted Potatoes

For planting April-May:

• Acquire seed potatoes in January-February.
• Store at 38-40°F in complete darkness until 2-4 weeks before planting.
• Move to a warm, light location 2-4 weeks before planting to trigger sprouting.

Fall Planted Potatoes

For planting July-August:

• Obtain seed potatoes in May-June.
• Keep at 38-40°F in darkness for 8-12 weeks until ready to plant.
• Allow tubers to sprout just before planting.

Proper cold storage keeps potatoes dormant until the right time to sprout.

Ideal Seed Potato Storage Conditions

Whether storing for a few weeks or months, aim for conditions as close as possible to:

• Temperature: 38-40°F. Colder risks damage. Warmer causes premature sprouting.
• Humidity: 90-95% humidity. Helps prevent shriveling.
• Air Circulation: Good airflow to avoid condensation.
• Light: Total darkness. Light triggers sprouting.
• Containers: Perforated bags, crates or burlap sacks. Allows air movement.

Monitor conditions regularly and adjust as needed. Improper storage invites disease and sprouting problems.

Where to Store Seed Potatoes

Here are some suitable storage locations:

• Root cellar – The ideal traditional option if temperatures and humidity are right.
• Unheated basement room – Provides darkness and cool conditions. Use fans for airflow and humidifier to raise humidity.
• Refrigerator – Works for short term storage (1-3 months). Use perforated plastic bags and keep humidity high.
• Garage or shed – Can work if temperatures are cool. Insulate with blankets and use portable coolers as needed.
• Commercial potato storage units – Maintain exact conditions but expensive for home use.

Choose the best option you can manage based on your climate and planting timeframe.

Monitoring Potatoes in Storage

Check stored seed potatoes every 2-4 weeks and watch for:

• Sprouting – Rub off sprouts immediately to keep tubers dormant longer.
• Shriveling – Increase humidity if skins become wrinkled.
• Rotting – Remove and discard any potatoes with soft, mushy spots.
• Greening – Sign of light exposure. Keep containers completely dark.
• Mold – Indicates excess moisture. Improve ventilation if present.

Promptly addressing any issues in storage reduces losses and keeps your seed potatoes viable.

When to Stop Storing and Sprout Potatoes

• End cold storage when sprouts reach 1/4-1/2 inch, typically 2-4 weeks before planting.
• Move to a warm (60-70°F) well-lit area to green up sprouts and strengthen stems.
• Allow sprouts to turn green before planting. Avoid letting sprouts get leggy or exceed 1 inch.
• Plant sprouted potatoes immediately for best results rather than re-storing.

Properly pre-sprouting potatoes hardens them off for vigorous establishment after planting.

Storing Extra Seed Potatoes

If storing more seed tubers than needed:

• Clearly label potato varieties to avoid mixing them up.
• Use oldest seed potatoes first the following season.
• Check frequently and remove any tubers that shrivel or sprout while in storage.

With attention and care, seed potatoes can be stored successfully for several months leading up to planting.

FAQ About Seed Potato Storage

How long can I store seed potatoes before planting?

4-6 months is ideal. Storage longer than 8 months risks weaker plants and lower yields. Avoid carrying over seed potatoes for multiple seasons.

What causes seed potatoes to sprout early in storage?

Temperatures above 40°F, light exposure, excessive humidity, poor air circulation, or damage trigger premature sprouting.

Why shouldn’t I store seed potatoes from my garden harvest?

Homegrown potatoes lack the disease protections of certified seed. Start each season with fresh, robust certified seed potatoes.

Can I still plant green sprouted potatoes?

Yes. Allow green sprouts to grow larger under light before planting. Just rub off any very long sprouts before planting.

How do I know if seed potatoes are rotten from storage?

Rotten potatoes have soft, watery textures. Cut away any suspect areas – if the flesh is discolored versus white, it is likely rotted. Discard severely rotten potatoes.

Caring for your seed potato crop between seasons prepares them for a vigorous start once planted. With the right storage, you’ll begin with strong sprouted potatoes ready to grow.