One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's a good idea to plant platycodon in Markham by checking out the USDA zone info.

Planting Calendar for Platycodon

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

Platycodon do ok in moderate cold 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 platycodon 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 platycodon and expect a good harvest is probably August. Any later than that and your platycodon may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your platycodon indoors.

Last Frost Date

On average the last frost is on April 15 in Markham. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Markham may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Markham last frost occurs after April 15 so always be ready to protect your platycodon if you have a 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.