One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to determine when you can plant sunflowers by referring to the USDA zone info for Harvey.

Planting Calendar for Sunflowers

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

Sunflowers are not cold tolerant which means that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant sunflowers in Harvey 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. Any later than that and your sunflowers may not have a chance to fully mature. If you are starting your sunflowers indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Harvey the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -15°F.

Since the USDA zone info for Harvey is an average the actual date of last frost will vary from year to year. Half of the time in Harvey last frost occurs after April 15 so always be ready to protect your sunflowers in the event of one of those late frosts.

USDA Zone Info for Harvey

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 Harvey

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