One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Eureka you can determine when it's a good idea to plant onions by checking out the USDA zone info.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions do well in cold which tells us that you can start planting them much earlier than more sensitive plants.

The earliest that you can plant onions in Eureka is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant onions and expect a good harvest is probably September. If you wait any later than that and your onions may not have a chance to fully mature. You can get started a little bit earlier by starting your onions indoors.

Last Frost Date

In Eureka the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Keep in mind that USDA zone info for Eureka may not be accurate from year to year and the actual date of last frost is different every year. Since half of the time in Eureka you get surprised by a frost after April 15 be ready to protect your onions if you have a surprise late frost.

USDA Zone Info for Eureka

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Eureka

You may be interested in your other planting guides for Eureka.