white rot - Idaho Quarantine Zone and seed garlic

If you’re growing garlic or onions in southern Idaho or parts of eastern Oregon, you’re farming in one of the most closely protected allium zones in the country. Why? To stop a nasty soil-borne disease called white rot—a garlic grower’s worst nightmare.

Let’s break it down: This isn’t just another farm regulation—it’s a safeguard for soil health, crop yield, and your bottom line.

looking at a map

What Is the Idaho Allium Quarantine?

The Idaho Allium Quarantine is a state-enforced plant health zone designed to prevent the spread of white rot, a destructive fungus that affects alliums like garlic, onions, leeks, and shallots.

The quarantine covers 21 counties in Idaho and Malheur County in Oregon, restricting what kind of garlic or onions can be planted in the zone. Only seed stock that is grown, inspected, and certified within the zone can legally be planted there.

Counties in the Quarantine Zone:

Idaho: Ada, Bingham, Blaine, Boise, Bonneville, Canyon, Cassia, Elmore, Gem, Gooding, Jefferson, Jerome, Lincoln, Madison, Minidoka, Owyhee, Payette, Power, Twin Falls, and Washington

Oregon: Malheur County

Why Does It Exist?

White rot is caused by a soil-borne fungus (Sclerotium cepivorum) that targets garlic and other alliums. The bad news? Once it’s in the soil, it can stay dormant for up to 20 + years—waiting to pounce on your next allium crop.

It spreads easily through:

• Contaminated planting material

• Soil on tools and boots

• Water runoff and irrigation

• Flooding and farm equipment

  
  

Southern Idaho is a major player in the U.S. onion industry, worth around $55 million annually. The quarantine helps protect that industry—and your soil—from this long-lived pathogen.

what Growers Need to Know

If You're Planting Inside the Quarantine Zone:

• You can only plant certified garlic or onion seed stock grown within the zone.

• All planting material must be inspected and approved by the Idaho State Department of Agriculture (ISDA).

  
  

Bringing Garlic Into the Quarantine Zone:

• Seed garlic from outside the zone must undergo rigorous testing to prove it’s free of white rot before it can be planted.

• Onion seeds (not sets) are not regulated the same way, as they’re far less likely to carry the fungus.

• Garlic Gods has brought in several varieties of garlic, sending it to the University of Idaho for vigorous testing prior to planting - because of this testing, it takes us several years before we can sell new varieties to the public.

  
  

What It Means for Growers

Certified seed garlic growing in Rupert, ID

While the quarantine protects farms and the industry, it also comes with some challenges:

• Fewer garlic varieties are available to local growers

• Importing heirloom or specialty garlic can be tricky

• Starting a new garlic-growing operation requires careful sourcing

  
  

Garlic Gods: Your Certified Source for Clean Seed Garlic

At Garlic Gods, we farm within the Idaho Allium Quarantine zone, and we’re proud to offer garlic that meets every requirement:

• Certified white rot–free by the Idaho State Department of Agriculture

• Hand-harvested, cured, and packed on our farm

• Includes both softneck garlic for warm climates and hardneck garlic for cold regions

Planting Inside the Quarantine Zone?

We've got you covered. All our Idaho-grown seed garlic is 100% compliant and perfect for growers inside the quarantine area, as well as growers throughout the United States.

👉 Order online today at garlicgods.com or call/text Jana at 208-260-8966 for help selecting certified varieties.

Garlic Gods: Grown clean. Certified strong. Trusted by growers.