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.

It's a good idea to determine when to plant sweet williams by using the USDA zone info for Downingtown.

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 are moderately cold tolerant.

The earliest that you can plant sweet williams in Downingtown 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 grow to maturity. If you are starting your sweet williams indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Downingtown. It might get as low as -5°F during the coldest months of winter.

Keep in mind that USDA zone info for Downingtown is just an average and the actual date of last frost changes from year to year. Since half of the time in Downingtown you get surprised by a frost after April 15 be ready to cover your sweet williams if you have a late frost.

USDA Zone Info for Downingtown

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Downingtown

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