Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of determining when to plant dahlia is to examine the USDA zone info for Umatilla.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Dahlia require warm weather which means that it's necessary to wait until it warms up after the last frost before you can plant them.

The earliest that you can plant dahlia 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 dahlia and expect a good harvest is probably August. Any later than that and your dahlia may not have a chance to grow to maturity. Starting your dahlia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Umatilla the average date of last frost happens on April 15. It might get as low as 5°F during the coldest months of winter.

Just be sure to 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 is different every year. Half of the time in Umatilla last frost occurs after April 15 so just be sure to be ready to protect your dahlia if you have one of those late frosts.

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.