Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of making a decision about when it's a good idea to plant sunflowers is to examine the USDA zone info for Le Mars.

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 has passed because they are not cold tolerant.

The earliest that you can plant sunflowers in Le Mars 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. If you wait any later than that and your sunflowers may not have a chance to grow to maturity. If you are starting your sunflowers indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Le Mars the average date of last frost happens on April 15. It might get as low as -20°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Le Mars and it changes from year to year. Since half of the time in Le Mars you get a frost after April 15 be ready to cover your sunflowers if you have one of those late frosts.

USDA Zone Info for Le Mars

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Le Mars

You may be interested in your other planting guides for Le Mars.