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.

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

Planting Calendar for Garden cress

Frost tolerance for garden cress:	Not tolerant of frost.
When to plant:	After the last frost has passed.

You should not plant garden cress until after the last frost because they do not do well in cold weather.

The earliest that you can plant garden cress 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 garden cress and expect a good harvest is probably August. You probably don't want to wait any later than that or else your garden cress may not have a chance to fully mature. If you are starting your garden cress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Helena the average date of last frost happens on March 15. You can expect an average low temperature of 10°F in the coldest months of winter.

Keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Helena and it is different every year. Half of the time in Helena you get surprised by a frost after March 15 so make sure that you are prepared to protect your garden cress in the event of one of those late frosts.

USDA Zone Info for Helena

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Helena

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