One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

By reviewing the USDA zone info for Delta you will be able to estimate when it's possible to plant calendula.

Planting Calendar for Calendula

Frost tolerance for calendula:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since calendula do well in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant calendula in Delta 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 calendula and expect a good harvest is probably September. If you wait any later than that and your calendula may not have a chance to fully mature. If you are starting your calendula indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Delta. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Delta is an average the actual date of last frost changes from year to year. Half of the time in Delta there is a last frost after April 15 so always be ready to cover your calendula in the event of a surprise late frost.

USDA Zone Info for Delta

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 Delta

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