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.

By referring to the USDA zone info for Markham it's possible to figure out when to plant sweet potatos.

Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos:	Not tolerant of frost.
When to plant:	After the last frost.

Since sweet potatos are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant sweet potatos in Markham is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sweet potatos and expect a good harvest is probably August. If you wait any later than that and your sweet potatos may not have a chance to fully mature. If you are starting your sweet potatos indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Markham and it can change quite a bit from year to year. Half of the time in Markham it frosts late in the year after April 15 so make sure that you are ready to protect your sweet potatos in the event of one of those late frosts.

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.