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 should be able to figure out when you can plant mustard by referring to the USDA zone info for Belfast.

Planting Calendar for Mustard

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

Mustard do not do well in cold weather which tells us that you must wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant mustard in Belfast 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. You probably don't want to wait any later than that or else your mustard may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your mustard indoors.

Last Frost Date

In Belfast the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Belfast is not always accurate the actual date of last frost changes from year to year. Since half of the time in Belfast there is a last frost after April 15 be ready to protect your mustard if you have one of those late frosts.

USDA Zone Info for Belfast

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 Belfast

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