One of the best tools that you have as gardeners to help us determine 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 getting a good idea when you can plant celery is to examine the USDA zone info for Denver.

Planting Calendar for Celery

Frost tolerance for celery:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since celery are barely cold tolerant you can plant them slightly earlier in the year than other frost tender plants.

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

The last month that you can plant celery and expect a good harvest is probably August. You probably don't want to wait any later than that or else your celery may not have a chance to really do well. You can get started a few weeks earlier by starting your celery indoors.

Last Frost Date

In Denver the average date of last frost happens on April 15. You should expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Denver may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Denver there is a last frost after April 15 so just be sure to be ready to cover your celery in the event of a surprise late frost.

USDA Zone Info for Denver

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 Denver

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