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

It's possible to figure out when you can plant dahlia by looking at the USDA zone info for Watsonville.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's probably not a good idea to plant dahlia until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant dahlia in Watsonville 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. You probably don't want to wait any later than that or else 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 little bit earlier.

Last Frost Date

In Watsonville the average date of last frost happens on February 15. It might get as low as 25°F during the coldest months of winter.

Remember that USDA zone info for Watsonville is an average and the actual date of last frost is different every year. Half of the time in Watsonville there is a last frost after February 15 so just be sure to be ready to protect your dahlia in the event of a late frost.

USDA Zone Info for Watsonville

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Watsonville

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