The USDA Zone info is a great tool for gardeners to help us determine your gardening 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 estimating when it's the best time to plant cosmos is to examine the USDA zone info for Cupertino.

Planting Calendar for Cosmos

Frost tolerance for cosmos:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant cosmos a bit earlier in the year because they are barely cold tolerant.

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

The last month that you can plant cosmos and expect a good harvest is probably September. If you wait any later than that and your cosmos may not have a chance to really do well. Starting your cosmos indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is February 15 in Cupertino. In the coldest months of winter you can expect an average low temperature of 25°F.

Always keep in mind 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 Cupertino and it will vary from year to year. Half of the time in Cupertino last frost occurs after February 15 so make sure that you are ready to protect your cosmos in the event of a surprise late frost.

USDA Zone Info for Cupertino

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 Cupertino

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