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When to Plant Bunching Onions in Great Falls, MT

Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You should be able to determine when you can plant bunching onions by reviewing the USDA zone info for Great Falls.


Planting Calendar for Bunching Onions

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

Bunching Onions are one of those plants that can tolerate a tiny bit of cold weather which means that you can start planting them slightly earlier than other plants that might not handle the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant bunching onions
Possibly ok, but a risky time to plant bunching onions
Probably not a good time to plant bunching onions

The earliest that you can plant bunching onions in Great Falls 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 bunching onions and expect a good harvest is probably August. If you wait any later than that and your bunching onions may not have a chance to really do well. Starting your bunching onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on May 15 in Great Falls. It might get as low as -30°F during the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Great Falls and it will vary from year to year. Half of the time in Great Falls you get a frost after May 15 so make sure that you are prepared to protect your bunching onions in the event of one of those late frosts.

USDA Zone Info for Great Falls

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 Great Falls

You may be interested in your other planting guides for Great Falls.