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.

The first chance to plant sunflowers in Happy Valley can be figured out by referring to the USDA zone info.

Planting Calendar for Sunflowers

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

It's probably not a good idea to plant sunflowers until after the last frost because they are not cold tolerant.

The earliest that you can plant sunflowers in Happy Valley 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. Any later than that and your sunflowers may not have a chance to really do well. 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

The average date of last frost is March 15 in Happy Valley. You can expect an average low temperature of 15°F in the coldest months of winter.

Since the USDA zone info for Happy Valley is an average the actual date of last frost will vary from year to year. Since half of the time in Happy Valley there is a last frost after March 15 be ready to protect your sunflowers in the event of one of those late frosts.

USDA Zone Info for Happy Valley

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 Happy Valley

You may be interested in your other planting guides for Happy Valley.