When can I plant Four O' Clock in Zone 1a

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

The earliest that you can plant four o' clock in Zone 1a can be determined by using the USDA zone info.


Planting Calendar for Four O' Clock

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

You should not plant four o' clock until after the last frost because they require warm weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant four o' clock
Possibly ok, but a risky time to plant four o' clock
Probably not a good time to plant four o' clock

The earliest that you can plant four o' clock in Zone 1a is June. However, you really should wait until July 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 July. You probably don't want to wait any later than that or else your four o' clock may not have a chance to grow to maturity. Starting your four o' clock indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Zone 1a the average date of last frost happens on June 15. We can expect an average low temperature of -60°F in the coldest months of winter.

Keep in mind that USDA zone info for Zone 1a may not be accurate from year to year and our actual date of last frost will vary from year to year. Since half of the time in Zone 1a we get a frost after June 15 be ready to cover your four o' clock in the event of a surprise late frost.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)June 15
Average Date of First Frost (fall)July 15
Lowest Expected Low-60°F
Highest Expected Low-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in our other planting guides for Zone 1a.