One of the first steps you take when you are getting a good idea 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.

The earliest that you can plant sweet williams in Lake Oswego should be determined by using 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.

Sweet Williams are moderately cold tolerant which means that you can plant them a little bit earlier than more sensitive plants.

The earliest that you can plant sweet williams in Lake Oswego 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. You probably don't want to wait any later than that or else your sweet williams may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your sweet williams indoors.

Last Frost Date

The average date of last frost is March 15 in Lake Oswego. You can expect an average low temperature of 15°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 Lake Oswego and it changes from year to year. Since half of the time in Lake Oswego it frosts late in the year after March 15 be ready to protect your sweet williams if you have a late frost.

USDA Zone Info for Lake Oswego

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Lake Oswego

You may be interested in your other planting guides for Lake Oswego.