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.

One way of getting a good idea when it's the best time to plant heliotrope is to use the USDA zone info for Princeton.

Planting Calendar for Heliotrope

Frost tolerance for heliotrope:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since heliotrope are not cold tolerant you must wait until after the last frost when the weather gets warmer before you can plant them.

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

Last Frost Date

In Princeton the average date of last frost happens on April 15. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Princeton 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 Princeton last frost occurs after April 15 so be sure to be ready to protect your heliotrope if you have a late frost.

USDA Zone Info for Princeton

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 Princeton

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