One of the first steps you take when you are making a decision about 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.

It's possible to determine when to plant sunflowers by referring to the USDA zone info for Herndon.

Planting Calendar for Sunflowers

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

You really shouldn't plant sunflowers until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant sunflowers in Herndon 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 Herndon the average date of last frost happens on April 15. You should expect an average low temperature of 0°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Herndon and it is different every year. Since half of the time in Herndon you get surprised by a frost after April 15 be ready to cover your sunflowers if you have a late frost.

USDA Zone Info for Herndon

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Herndon

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