Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Plymouth you can determine when to plant delphinium by reviewing 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.

You can plant delphinium a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant delphinium in Plymouth 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. Starting your delphinium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Plymouth. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Plymouth is not always accurate the actual date of last frost is different every year. Since half of the time in Plymouth last frost occurs after April 15 be ready to cover your delphinium if you have one of those late frosts.

USDA Zone Info for Plymouth

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Plymouth

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