Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of determining when it's the best time to plant celosia is to refer to the USDA zone info for Markham.

Planting Calendar for Celosia

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

Celosia require warm weather which tells us that it's necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant celosia in Markham 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. If you wait any later than that and your celosia may not have a chance to grow to maturity. If you are starting your celosia indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Markham may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Half of the time in Markham you get surprised by a frost after April 15 so make sure that you are prepared to cover your celosia in the event of a late frost.

USDA Zone Info for Markham

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 Markham

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