One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

One way of determining when it's the best time to plant calendula is to check out the USDA zone info for Lombard.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant calendula just a bit earlier in the year because they do well in moderate cold.

The earliest that you can plant calendula in Lombard is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant calendula and expect a good harvest is probably September. If you wait any later than that and your calendula may not have a chance to really do well. Starting your calendula 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 Lombard. In the coldest months of winter you should expect an average low temperature of -15°F.

Remember 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 Lombard and it can change quite a bit from year to year. Half of the time in Lombard it frosts late in the year after April 15 so always be ready to protect your calendula in the event of a late frost.

USDA Zone Info for Lombard

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 Lombard

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