One of the first steps you take when you are determining 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.

A common way of getting a good idea when to plant sweet williams is to use the USDA zone info for Silvis.

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 Silvis 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. If you wait any later than that and your sweet williams may not have a chance to really do well. Starting your sweet williams indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Silvis the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Silvis is an average the actual date of last frost is different every year. Since half of the time in Silvis 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 Silvis

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Silvis

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