One of the first steps you take when you are determining 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.

The earliest that you can plant primula in Lewiston can be determined 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.

Primula tend to make it in quite a bit of cold which tells us that you can plant them earlier in the year than other frost tender plants.

The earliest that you can plant primula in Lewiston 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 fully mature. Starting your primula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Lewiston the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of 5°F.

Since the USDA zone info for Lewiston is just an average the actual date of last frost changes from year to year. Half of the time in Lewiston there is a last frost after April 15 so make sure that you are prepared to cover your primula if you have a late frost.

USDA Zone Info for Lewiston

Here is the info for USDA Zone 7b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	5°F
Highest Expected Low	10°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 10°F.

Plants to Grow in Lewiston

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