One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

In Havre you can figure out when it's the best time to plant marigold by referring to the USDA zone info.

Planting Calendar for Marigold

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

It's not a good idea to plant marigold until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant marigold in Havre 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 marigold and expect a good harvest is probably August. Any later than that and your marigold may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your marigold indoors.

Last Frost Date

The average date of last frost is May 15 in Havre. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Havre may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Havre there is a last frost after May 15 so make sure that you are prepared to cover your marigold in the event of a late frost.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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