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 estimate when it's possible to plant alyssum by looking at the USDA zone info for Belfast.

Planting Calendar for Alyssum

Frost tolerance for alyssum:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Alyssum do well in quite a bit of cold which means that you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant alyssum in Belfast is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant alyssum and expect a good harvest is probably September. Any later than that and your alyssum may not have a chance to really do well. You can get started a few weeks earlier by starting your alyssum indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Belfast. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that USDA zone info for Belfast is not always accurate and the actual date of last frost is different every year. Since half of the time in Belfast it frosts late in the year after April 15 be ready to protect your alyssum 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.