Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Manhattan you can estimate when it's possible to plant welsh onion by using the USDA zone info.

Planting Calendar for Welsh onion

Frost tolerance for welsh onion:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Welsh onion are one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant welsh onion in Manhattan 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 welsh onion and expect a good harvest is probably August. Any later than that and your welsh onion may not have a chance to fully mature. You can get started a few weeks earlier by starting your welsh onion indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Manhattan. It might get as low as -10°F during the coldest months of winter.

It's important to remember that USDA zone info for Manhattan may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in Manhattan you get surprised by a frost after April 15 be ready to protect your welsh onion if you have a late frost.

USDA Zone Info for Manhattan

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 Manhattan

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