Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to determine when to plant mustard by looking at the USDA zone info for Longmont.

Planting Calendar for Mustard

Frost tolerance for mustard:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant mustard until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant mustard in Longmont 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 mustard and expect a good harvest is probably August. Any later than that and your mustard may not have a chance to grow to maturity. Starting your mustard indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Remember that USDA zone info for Longmont is not always accurate and the actual date of last frost changes from year to year. Half of the time in Longmont you get surprised by a frost after April 15 so always be ready to protect your mustard if you have one of those late frosts.

USDA Zone Info for Longmont

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

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

Plants to Grow in Longmont

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