The USDA Zone info is a great tool for gardeners to help us estimate 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.

It's a good idea to figure out when it's possible to plant four-o-clock flower by looking at the USDA zone info for Belfast.

Planting Calendar for Four-o-clock flower

Frost tolerance for four-o-clock flower:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since four-o-clock flower do not do well in cold weather you need to wait until after the last frost before you can plant them.

The earliest that you can plant four-o-clock flower 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 four-o-clock flower and expect a good harvest is probably August. Any later than that and your four-o-clock flower may not have a chance to really do well. You can get started a few weeks earlier by starting your four-o-clock flower indoors.

Last Frost Date

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

Just be sure to remember that USDA zone info for Belfast is just an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Belfast last frost occurs after April 15 so just be sure to be ready to protect your four-o-clock flower in the event of a late frost.

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.