The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to estimate when it's the best time to plant onions by looking at the USDA zone info for Trenton.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

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

The earliest that you can plant onions in Trenton 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 onions and expect a good harvest is probably September. You probably don't want to wait any later than that or else your onions may not have a chance to grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Trenton. In the coldest months of winter you can expect an average low temperature of -10°F.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Trenton and it will vary from year to year. Half of the time in Trenton you get surprised by a frost after April 15 so make sure that you are ready to cover your onions if you have a surprise late frost.

USDA Zone Info for Trenton

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 Trenton

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