One of the first steps you take when you are getting a good idea 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 looking at the USDA zone info for Allentown you should be able to determine when it's possible to plant sunflowers.

Planting Calendar for Sunflowers

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

Sunflowers do not do well in cold weather which tells us that it is important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant sunflowers 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 sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to grow to maturity. Starting your sunflowers indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is 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 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 Allentown it frosts late in the year after April 15 be ready to cover your sunflowers 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.