One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of figuring out when it's the best time to plant four o' clock is to examine the USDA zone info for Boston.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After the last frost.

Four O' Clock require warm weather which means that it is necessary to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant four o' clock 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 and expect a good harvest is probably August. Any later than that and your four o' clock may not have a chance to really do well. If you are starting your four o' clock indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Boston. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Boston may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Boston last frost occurs after April 15 so just be sure to be ready to protect your four o' clock if you have one of those late frosts.

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.