One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Allentown it's possible to figure out when it's the best time 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 do well in mild cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Allentown 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 really do well. You can get started a few weeks earlier by starting your delphinium indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Allentown. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Allentown is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Allentown it frosts late in the year after April 15 so make sure that you are ready to cover your delphinium in the event of a late frost.

USDA Zone Info for Allentown

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 Allentown

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