The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first chance to plant four-o-clock flower in Boston should be figured out by looking at the USDA zone info.

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.

It's not a good idea to plant four-o-clock flower until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant four-o-clock flower in Boston 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. Starting your four-o-clock flower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Boston the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Boston and it can change quite a bit from year to year. Half of the time in Boston you get a frost after April 15 so just be sure to be ready to cover your four-o-clock flower in the event of a surprise late frost.

USDA Zone Info for Boston

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Boston

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