One of the best tools that you have as gardeners to help us figure out 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 Gaithersburg you can estimate when it's possible to plant astilbe by using the USDA zone info.

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.

Since astilbe are one of those plants that can tolerate a tiny bit of cold weather you can plant them slightly earlier in the year than more sensitive plants.

The earliest that you can plant astilbe in Gaithersburg 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. You probably don't want to wait any later than that or else your astilbe may not have a chance to really do well. If you are starting your astilbe indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Gaithersburg. You can expect an average low temperature of 0°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Gaithersburg and it changes from year to year. Half of the time in Gaithersburg there is a last frost after April 15 so just be sure to be ready to protect your astilbe in the event of a surprise late frost.

USDA Zone Info for Gaithersburg

Here is the info for USDA Zone 7a.

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

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

Plants to Grow in Gaithersburg

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