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When to Plant Asparagus in Napa, CA

One of the best tools that you have as gardeners to help us determine 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.

It's a good idea to determine when it's a good idea to plant asparagus by referring to the USDA zone info for Napa.


Planting Calendar for Asparagus

Frost tolerance for asparagus: Very tolerant of frost.
When to plant: Up to 7 weeks before last frost.

Asparagus are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them much earlier than more sensitive plants.

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

The earliest that you can plant asparagus in Napa 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 asparagus and expect a good harvest is probably October. If you wait any later than that and your asparagus may not have a chance to really do well. If you are starting your asparagus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

It's important to remember 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 Napa and it can change quite a bit from year to year. Since half of the time in Napa there is a last frost after February 15 be ready to protect your asparagus in the event of one of those late frosts.

USDA Zone Info for Napa

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 Low25°F
Highest Expected Low30°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 Napa

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