One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of getting a good idea when you can plant astilbe is to consult the USDA zone info for Cranston.

Planting Calendar for Astilbe

Frost tolerance for astilbe:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Astilbe are barely cold tolerant which tells us that you can get them planted just a bit earlier than other frost tender plants.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Cranston. It might get as low as -5°F during the coldest months of winter.

Keep in mind that USDA zone info for Cranston is an average and the actual date of last frost is different every year. Since half of the time in Cranston you get surprised by a frost after April 15 be ready to cover your astilbe if you have a surprise late frost.

USDA Zone Info for Cranston

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Cranston

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