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.

One way of estimating when it's possible to plant four o' clock is to look at the USDA zone info for Cambridge.

Planting Calendar for Four O' Clock

Frost tolerance for four o' clock:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

It's probably a bad idea to plant four o' clock until after the last frost has passed because they require warm weather.

The earliest that you can plant four o' clock in Cambridge 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. If you wait any later than that and your four o' clock may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your four o' clock indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Cambridge. You can expect an average low temperature of -10°F in the coldest months of winter.

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Cambridge and it can change quite a bit from year to year. Since half of the time in Cambridge you get a frost after April 15 be ready to cover your four o' clock in the event of a surprise late frost.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Cambridge

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