One of the first steps you take when you are getting a good idea 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 should be able to estimate when it's possible to plant celosia by using the USDA zone info for Hillsboro.

Planting Calendar for Celosia

Frost tolerance for celosia:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably not a good idea to plant celosia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant celosia in Hillsboro is April. However, you really should wait until May if you don't want to take any chances.

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

Last Frost Date

In Hillsboro the average date of last frost happens on March 15. In the coldest months of winter you can expect an average low temperature of 10°F.

It's important to remember that USDA zone info for Hillsboro is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Hillsboro you get a frost after March 15 be ready to protect your celosia if you have one of those late frosts.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Hillsboro

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