One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to estimate when it's possible to plant indian cress by reviewing the USDA zone info for Helena.

Planting Calendar for Indian cress

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

Since indian cress are not cold tolerant you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant indian cress in Helena is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant indian cress and expect a good harvest is probably August. Any later than that and your indian cress may not have a chance to fully mature. If you are starting your indian cress indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Helena. You should expect an average low temperature of -25°F in the coldest months of winter.

It's important to remember that USDA zone info for Helena may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Helena it frosts late in the year after May 15 be ready to cover your indian cress if you have one of those late frosts.

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.