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.

One way of estimating when it's possible to plant asters is to look at the USDA zone info for Oskaloosa.

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 a bit earlier in the year than other frost tender plants.

The earliest that you can plant asters in Oskaloosa 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 asters and expect a good harvest is probably September. You probably don't want to wait any later than that or else your asters may not have a chance to grow to maturity. Starting your asters indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Oskaloosa. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Oskaloosa is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Oskaloosa there is a last frost after April 15 so just be sure to be ready to cover your asters in the event of a surprise late frost.

USDA Zone Info for Oskaloosa

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 Oskaloosa

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