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

You can determine when to plant bunching onions in Markham by checking out the USDA zone info.

Planting Calendar for Bunching Onions

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

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

The earliest that you can plant bunching onions in Markham 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 bunching onions and expect a good harvest is probably August. You probably don't want to wait any later than that or else your bunching onions may not have a chance to really do well. Starting your bunching onions indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Markham the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Markham is just an average and the actual date of last frost changes from year to year. Half of the time in Markham you get surprised by a frost after April 15 so just be sure to be ready to protect your bunching onions if you have a surprise late frost.

USDA Zone Info for Markham

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 Markham

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