One of the first steps you take when you are making a decision about 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.

You can determine when it's possible to plant calendula in Romulus by looking at the USDA zone info.

Planting Calendar for Calendula

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

Since calendula are moderately cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant calendula in Romulus 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. You probably don't want to wait any later than that or else your calendula may not have a chance to fully mature. Starting your calendula indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Romulus the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Romulus may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Romulus you get surprised by a frost after April 15 so always be ready to protect your calendula if you have a surprise late frost.

USDA Zone Info for Romulus

Here is the info for USDA Zone 6a.

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

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Romulus

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