One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to determine when to plant tall phlox by using the USDA zone info for Platteville.

Planting Calendar for Tall Phlox

Frost tolerance for tall phlox:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Tall Phlox are moderately cold tolerant which tells us that you can start planting them earlier than other frost tender plants.

The earliest that you can plant tall phlox in Platteville is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant tall phlox and expect a good harvest is probably September. Any later than that and your tall phlox may not have a chance to grow to maturity. Starting your tall phlox indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Since the USDA zone info for Platteville is an average the actual date of last frost changes from year to year. Since half of the time in Platteville you get a frost after April 15 be ready to protect your tall phlox if you have a surprise late frost.

USDA Zone Info for Platteville

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 Platteville

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