One of the first steps you take when you are figuring out 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.

By referring to the USDA zone info for Warrenville you should be able to figure out when it's the best time to plant bidens.

Planting Calendar for Bidens

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

It's probably a bad idea to plant bidens until after the last frost because they are not cold tolerant.

The earliest that you can plant bidens in Warrenville 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 bidens and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bidens may not have a chance to really do well. If you are starting your bidens indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Warrenville is not always accurate the actual date of last frost will vary from year to year. Half of the time in Warrenville you get a frost after April 15 so make sure that you are prepared to protect your bidens in the event of one of those late frosts.

USDA Zone Info for Warrenville

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 Warrenville

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