Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You should be able to figure out when to plant asters by looking at the USDA zone info for Marlborough.

Planting Calendar for Asters

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

Asters are moderately cold tolerant which tells us that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant asters in Marlborough 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. Any later than that and your asters may not have a chance to fully mature. If you are starting your asters indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Marlborough the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Marlborough may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Marlborough you get a frost after April 15 be ready to cover your asters in the event of one of those late frosts.

USDA Zone Info for Marlborough

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Marlborough

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