Before planting it is a good idea to find your USDA Zone info to estimate 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.

One way of getting a good idea when to plant primula is to consult the USDA zone info for Princeton.

Planting Calendar for Primula

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

Primula tend to make it in pretty solid cold which tells us that you can plant them much earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in Princeton 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. If you wait any later than that and your primula may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your primula indoors.

Last Frost Date

In Princeton the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Princeton is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Princeton it frosts late in the year after April 15 be ready to cover your primula if you have a surprise late frost.

USDA Zone Info for Princeton

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Princeton

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