One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Stillwater you can figure out when it's the best time to plant asters by checking out the USDA zone info.

Planting Calendar for Asters

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

Since asters do well in moderate cold you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant asters in Stillwater is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant asters and expect a good harvest is probably August. If you wait any later than that and your asters may not have a chance to really do well. You can get started a couple of weeks earlier by starting your asters indoors.

Last Frost Date

On average the last frost is on May 15 in Stillwater. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that USDA zone info for Stillwater is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Stillwater last frost occurs after May 15 so be sure to be ready to protect your asters if you have a surprise late frost.

USDA Zone Info for Stillwater

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Stillwater

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