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.

It's a good idea to determine when to plant heliotrope by referring to the USDA zone info for Allentown.

Planting Calendar for Heliotrope

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

It's a bad idea to plant heliotrope until after the last frost because they do not do well in cold weather.

The earliest that you can plant heliotrope in Allentown 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 heliotrope and expect a good harvest is probably August. If you wait any later than that and your heliotrope may not have a chance to fully mature. You can get started a few weeks earlier by starting your heliotrope indoors.

Last Frost Date

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

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Allentown and it will vary from year to year. Half of the time in Allentown it frosts late in the year after April 15 so always be ready to cover your heliotrope if you have one of those late frosts.

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.