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.

In Janesville you can determine when it's the best time to plant primula by referring to 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.

You can plant primula quite a bit earlier in the year because they do well in cold.

The earliest that you can plant primula in Janesville 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. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Janesville. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Janesville is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Janesville there is a last frost after April 15 be ready to protect your primula in the event of a late frost.

USDA Zone Info for Janesville

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Janesville

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