When to Plant Bunching Onions in Millbrae, CA

One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can figure out when it's possible to plant bunching onions in Millbrae by reviewing the USDA zone info.


Planting Calendar for Bunching Onions

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

You can plant bunching onions just a tiny bit earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant bunching onions
Possibly ok, but a risky time to plant bunching onions
Probably not a good time to plant bunching onions

The earliest that you can plant bunching onions in Millbrae 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 bunching onions and expect a good harvest is probably September. Any later than that and your bunching onions may not have a chance to really do well. Starting your bunching onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Millbrae is just an average the actual date of last frost is different every year. Half of the time in Millbrae you get a frost after January 31 so make sure that you are ready to protect your bunching onions in the event of one of those late frosts.

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 Low30°F
Highest Expected Low35°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.