One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In San Luis Obispo you can determine when you can plant dahlias by looking at the USDA zone info.

Planting Calendar for Dahlias

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

Dahlias are not cold tolerant which tells us that it's important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant dahlias in San Luis Obispo 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 dahlias and expect a good harvest is probably September. If you wait any later than that and your dahlias may not have a chance to really do well. Starting your dahlias indoors is a great way to get them started a little bit earlier.

Last Frost Date

In San Luis Obispo the average date of last frost happens on February 15. You should expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for San Luis Obispo is not always accurate the actual date of last frost can change quite a bit from year to year. Half of the time in San Luis Obispo it frosts late in the year after February 15 so make sure that you are ready to protect your dahlias if you have one of those late frosts.

USDA Zone Info for San Luis Obispo

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 San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.