The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Umatilla you can determine when it's the best time to plant sunflowers 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.

Sunflowers require warm weather which means that you have to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant sunflowers in Umatilla 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 fully mature. You can get started a couple of weeks earlier by starting your sunflowers indoors.

Last Frost Date

The average date of last frost is April 15 in Umatilla. You can expect an average low temperature of 5°F in the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Umatilla and it will vary from year to year. Half of the time in Umatilla there is a last frost after April 15 so make sure that you are ready to cover your sunflowers in the event of a late frost.

USDA Zone Info for Umatilla

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°F

This means that on a really cold year, the coldest it will get is 5°F. On most years you should be prepared to experience lows near 10°F.

Plants to Grow in Umatilla

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