One of the first steps you take when you are estimating 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.

A common way of making a decision about when you can plant four o' clock is to examine the USDA zone info for Pella.

Planting Calendar for Four O' Clock

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

Since four o' clock require warm weather it's necessary to wait until after the last frost before you can plant them.

The earliest that you can plant four o' clock in Pella 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. You can get started a few weeks earlier by starting your four o' clock indoors.

Last Frost Date

The average date of last frost is April 15 in Pella. It might get as low as -15°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Pella and it can change quite a bit from year to year. Since half of the time in Pella last frost occurs after April 15 be ready to protect your four o' clock if you have one of those late frosts.

USDA Zone Info for Pella

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 Pella

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