The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when to plant bunching onions by using the USDA zone info for Renton.

Planting Calendar for Bunching Onions

Frost tolerance for bunching onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since bunching onions do ok in moderate cold you can plant them slightly earlier in the year than other frost tender plants.

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

The last month that you can plant bunching onions and expect a good harvest is probably August. Any later than that and your bunching onions may not have a chance to really do well. You can get started a couple of weeks earlier by starting your bunching onions indoors.

Last Frost Date

In Renton the average date of last frost happens on March 15. You can expect an average low temperature of 15°F in the coldest months of winter.

It's important to remember that USDA zone info for Renton is an average and the actual date of last frost will vary from year to year. Half of the time in Renton there is a last frost after March 15 so always be ready to protect your bunching onions in the event of a surprise late frost.

USDA Zone Info for Renton

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Renton

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