Before planting it is a good idea to find your USDA Zone info to determine 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.

A common way of getting a good idea when it's a good idea to plant welsh onion is to examine the USDA zone info for Waterloo.

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.

You can plant welsh onion a bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant welsh onion in Waterloo 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. If you wait any later than that and your welsh onion may not have a chance to grow to maturity. If you are starting your welsh onion indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Waterloo the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

It's important to remember that USDA zone info for Waterloo is just an average and the actual date of last frost changes from year to year. Since half of the time in Waterloo you get surprised by a frost after April 15 be ready to cover your welsh onion if you have a surprise late frost.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

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