The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Lansdale it's a good idea to estimate when it's a good idea to plant delphinium.

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 are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can plant them slightly earlier than other frost tender plants.

The earliest that you can plant delphinium in Lansdale 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. If you wait any later than that and your delphinium may not have a chance to really do well. If you are starting your delphinium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Lansdale 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.

Since the USDA zone info for Lansdale may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Lansdale it frosts late in the year after April 15 be ready to protect your delphinium in the event of a surprise late frost.

USDA Zone Info for Lansdale

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 Lansdale

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