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.

In Oak Forest you can determine when to plant primula by using the USDA zone info.

Planting Calendar for Primula

Frost tolerance for primula:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since primula do well in cold you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant primula in Oak Forest is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant primula and expect a good harvest is probably September. Any later than that and your primula may not have a chance to really do well. Starting your primula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Oak Forest is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Oak Forest there is a last frost after April 15 so make sure that you are ready to cover your primula if you have one of those late frosts.

USDA Zone Info for Oak Forest

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 Oak Forest

You may be interested in your other planting guides for Oak Forest.