Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By looking at the USDA zone info for Cambridge it's possible to estimate when it's the best time to plant centaurea.

Planting Calendar for Centaurea

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

Centaurea do well in moderate cold which tells us that you can get them planted earlier than more sensitive plants.

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

The last month that you can plant centaurea and expect a good harvest is probably August. Any later than that and your centaurea may not have a chance to really do well. If you are starting your centaurea indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Cambridge the average date of last frost happens on May 15. You should expect an average low temperature of -30°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Cambridge and it changes from year to year. Half of the time in Cambridge it frosts late in the year after May 15 so make sure that you are prepared to cover your centaurea if you have one of those late frosts.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Cambridge

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