Before planting it is a good idea to find your USDA Zone info to determine 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.

The earliest that you can plant dahlia in Patterson can be estimated by referring to the USDA zone info.

Planting Calendar for Dahlia

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

You really shouldn't plant dahlia until after the last frost when the weather gets warmer because they are not cold tolerant.

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

The last month that you can plant dahlia and expect a good harvest is probably September. If you wait any later than that and your dahlia may not have a chance to fully mature. If you are starting your dahlia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Patterson the average date of last frost happens on February 15. In the coldest months of winter you should expect an average low temperature of 20°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Patterson and it can change quite a bit from year to year. Half of the time in Patterson it frosts late in the year after February 15 so be sure to be ready to cover your dahlia in the event of a surprise late frost.

USDA Zone Info for Patterson

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

This means that on a really cold year, the coldest it will get is 20°F. On most years you should be prepared to experience lows near 25°F.

Plants to Grow in Patterson

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