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.

In Modesto you can figure out when it's the best time to plant dahlia by reviewing 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.

It's not a good idea to 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 Modesto 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. Any later than that and your dahlia may not have a chance to fully mature. You can get started a few weeks earlier by starting your dahlia indoors.

Last Frost Date

On average the last frost is on February 15 in Modesto. It might get as low as 25°F during the coldest months of winter.

It's important to remember that USDA zone info for Modesto is just an average and the actual date of last frost will vary from year to year. Half of the time in Modesto you get surprised by a frost after February 15 so make sure that you are prepared to protect your dahlia in the event of one of those late frosts.

USDA Zone Info for Modesto

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 Modesto

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