The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Hannibal you will be able to determine when it's possible to plant marigold.

Planting Calendar for Marigold

Frost tolerance for marigold:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You should not plant marigold until after all chance of frost has passed because they require warm weather.

The earliest that you can plant marigold in Hannibal 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 marigold and expect a good harvest is probably August. Any later than that and your marigold may not have a chance to grow to maturity. If you are starting your marigold indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Hannibal. In the coldest months of winter you should expect an average low temperature of -10°F.

It's important to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Hannibal and it changes from year to year. Since half of the time in Hannibal you get surprised by a frost after April 15 be ready to protect your marigold if you have a late frost.

USDA Zone Info for Hannibal

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Hannibal

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