Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant celosia in Johnston should be figured out by referring to the USDA zone info.

Planting Calendar for Celosia

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

It's a bad idea to plant celosia until after the last frost has passed because they require warm weather.

The earliest that you can plant celosia in Johnston 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 celosia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your celosia may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your celosia indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Johnston. In the coldest months of winter you should expect an average low temperature of -20°F.

Remember that USDA zone info for Johnston is just an average and the actual date of last frost changes from year to year. Half of the time in Johnston last frost occurs after April 15 so make sure that you are ready to protect your celosia if you have a surprise late frost.

USDA Zone Info for Johnston

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 Johnston

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