The USDA Zone info is a great tool for gardeners to help us figure out 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.

A common way of figuring out when it's a good idea to plant celosia is to look at the USDA zone info for Zone 4a.

Planting Calendar for Celosia

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

You should not plant celosia until after the last frost when the weather gets warmer because they are not cold tolerant.

The earliest that you can plant celosia in Zone 4a is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant celosia and expect a good harvest is probably August. Any later than that and your celosia may not have a chance to fully mature. If you are starting your celosia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on May 15 in Zone 4a. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Zone 4a is an average the actual date of last frost is different every year. Since half of the time in Zone 4a you get surprised by a frost after May 15 be ready to cover your celosia in the event of a late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.