One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Campbell you can estimate when it's possible to plant sweet williams by looking at the USDA zone info.

Planting Calendar for Sweet Williams

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

You can plant sweet williams a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant sweet williams in Campbell 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 sweet williams and expect a good harvest is probably September. Any later than that and your sweet williams may not have a chance to fully mature. If you are starting your sweet williams indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Campbell the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -10°F.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Campbell and it will vary from year to year. Since half of the time in Campbell it frosts late in the year after April 15 be ready to protect your sweet williams in the event of a surprise late frost.

USDA Zone Info for Campbell

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Campbell

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