One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Columbus you should be able to estimate when you can plant primula.

Planting Calendar for Primula

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

Primula do ok in pretty solid cold which means that you can plant them a lot earlier in the year than other plants that might not handle the cold.

The earliest that you can plant primula in Columbus 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 really do well. If you are starting your primula indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost is on March 15 in Columbus. In the coldest months of winter you can expect an average low temperature of 15°F.

Since the USDA zone info for Columbus is not always accurate the actual date of last frost is different every year. Since half of the time in Columbus you get a frost after March 15 be ready to cover your primula in the event of a surprise late frost.

USDA Zone Info for Columbus

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Columbus

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