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

A way of getting a good idea when it's the best time to plant calendula is to look at the USDA zone info for Hillsboro.

Planting Calendar for Calendula

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

You can plant calendula a little bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant calendula in Hillsboro 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 grow to maturity. You can get started a few weeks earlier by starting your calendula indoors.

Last Frost Date

On average the last frost has passed is on April 15 in Hillsboro. It might get as low as -10°F during the coldest months of winter.

Remember that USDA zone info for Hillsboro may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Hillsboro you get a frost after April 15 so just be sure to be ready to cover your calendula in the event of a late frost.

USDA Zone Info for Hillsboro

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 Hillsboro

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