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.

A way of determining when it's the best time to plant sunflowers is to refer to the USDA zone info for Woodburn.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant sunflowers until after all chance of frost has passed because they require warm weather.

The earliest that you can plant sunflowers in Woodburn is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to grow to maturity. If you are starting your sunflowers indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Woodburn. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Woodburn is just an average the actual date of last frost changes from year to year. Since half of the time in Woodburn there is a last frost after March 15 be ready to cover your sunflowers if you have one of those late frosts.

USDA Zone Info for Woodburn

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 Woodburn

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