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.

The USDA zone info for Greencastle can be read to estimate when you can plant sunflowers.

Planting Calendar for Sunflowers

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

You can not plant sunflowers until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant sunflowers in Greencastle 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 Greencastle. You can expect an average low temperature of -15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Greencastle is just an average and the actual date of last frost will vary from year to year. Since half of the time in Greencastle there is a last frost after April 15 be ready to protect your sunflowers in the event of one of those late frosts.

USDA Zone Info for Greencastle

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 Greencastle

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