One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Trenton should be used to figure out when it's possible to plant onions.

Planting Calendar for Onions

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

Since onions do well in cold you can plant them quite a bit earlier in the year than plants that are more sensitive to the cold.

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. Any later than that and your onions may not have a chance to really do well. If you are starting your onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Trenton. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Trenton may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Trenton last frost occurs after April 15 be ready to protect your onions in the event of one of those late frosts.

USDA Zone Info for Trenton

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Trenton

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