One of the best tools that you have as gardeners to help us estimate 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.

You can figure out when it's the best time to plant celery in Helena by checking out the USDA zone info.

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 do ok in moderate cold you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant celery in Helena 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 celery and expect a good harvest is probably August. If you wait any later than that and your celery may not have a chance to fully mature. You can get started a few weeks earlier by starting your celery indoors.

Last Frost Date

The average date of last frost is May 15 in Helena. In the coldest months of winter you can expect an average low temperature of -25°F.

Keep in mind that USDA zone info for Helena is just an average and the actual date of last frost will vary from year to year. Half of the time in Helena you get surprised by a frost after May 15 so just be sure to be ready to protect your celery in the event of a late frost.

USDA Zone Info for Helena

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Helena

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