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.

You can estimate when it's the best time to plant primula in Watertown 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 are one of those plants that can tolerate quite a bit of cold weather 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 Watertown 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 primula and expect a good harvest is probably August. If you wait any later than that and your primula may not have a chance to really do well. You can get started a couple of weeks earlier by starting your primula indoors.

Last Frost Date

On average the last frost is on May 15 in Watertown. It might get as low as -30°F during the coldest months of winter.

Just be sure to remember that USDA zone info for Watertown is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Watertown it frosts late in the year after May 15 so always be ready to cover your primula if you have a surprise late frost.

USDA Zone Info for Watertown

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 Watertown

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