The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when you can plant columbine is to look at the USDA zone info for Millbrae.

Planting Calendar for Columbine

Frost tolerance for columbine:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since columbine are one of those plants that can tolerate a little bit of cold weather you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

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

The last month that you can plant columbine and expect a good harvest is probably October. Any later than that and your columbine may not have a chance to grow to maturity. Starting your columbine indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Millbrae the average date of last frost happens on January 31. In the coldest months of winter you can expect an average low temperature of 30°F.

Since the USDA zone info for Millbrae may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Millbrae there is a last frost after January 31 so make sure that you are ready to cover your columbine in the event of a surprise late frost.

USDA Zone Info for Millbrae

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Millbrae

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