One of the best tools that you have as gardeners to help us determine 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.

You should be able to figure out when to plant dahlia by looking at the USDA zone info for Mount Washington.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's not a good idea to plant dahlia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant dahlia in Mount Washington is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant dahlia and expect a good harvest is probably August. Any later than that and your dahlia may not have a chance to grow to maturity. You can get started a little bit earlier by starting your dahlia indoors.

Last Frost Date

In Mount Washington the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Mount Washington and it will vary from year to year. Half of the time in Mount Washington last frost occurs after April 15 so always be ready to cover your dahlia if you have one of those late frosts.

USDA Zone Info for Mount Washington

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 Mount Washington

You may be interested in your other planting guides for Mount Washington.