The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The first chance to plant diascia in Zone 4a can be figured out by reviewing the USDA zone info.

Planting Calendar for Diascia

Frost tolerance for diascia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant diascia just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant diascia in Zone 4a is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant diascia and expect a good harvest is probably August. If you wait any later than that and your diascia may not have a chance to fully mature. If you are starting your diascia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Zone 4a the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Keep in mind that USDA zone info for Zone 4a may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Zone 4a you get a frost after May 15 so just be sure to be ready to cover your diascia in the event of a late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.