The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant violas in Belfast should be determined by reviewing the USDA zone info.

Planting Calendar for Violas

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

Violas are one of those plants that can tolerate quite a bit of cold weather which means that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant violas 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 violas and expect a good harvest is probably September. If you wait any later than that and your violas may not have a chance to grow to maturity. If you are starting your violas indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Belfast. In the coldest months of winter you can 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 can change quite a bit from year to year. Since half of the time in Belfast last frost occurs after April 15 be ready to protect your violas in the event of 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.