Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Kennewick it's a good idea to determine when to plant sunflowers.

Planting Calendar for Sunflowers

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

You should not plant sunflowers until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant sunflowers in Kennewick 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. If you wait any later than that and your sunflowers may not have a chance to fully mature. 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 April 15 in Kennewick. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Kennewick may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Kennewick you get surprised by a frost after April 15 be ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Kennewick

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Kennewick

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