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.

In Northampton you can estimate when you can plant delphinium by looking at the USDA zone info.

Planting Calendar for Delphinium

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

Delphinium do well in very little cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant delphinium in Northampton 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 delphinium and expect a good harvest is probably August. Any later than that and your delphinium may not have a chance to fully mature. If you are starting your delphinium indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Northampton. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Northampton is just an average the actual date of last frost is different every year. Half of the time in Northampton there is a last frost after April 15 so just be sure to be ready to cover your delphinium if you have a surprise late frost.

USDA Zone Info for Northampton

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 Northampton

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