Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Platteville you can estimate when it's a good idea to plant tree onions by reviewing the USDA zone info.

Planting Calendar for Tree onions

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

Tree onions tend to make it in some cold which tells us that you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tree onions in Platteville 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 tree onions and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tree onions may not have a chance to grow to maturity. If you are starting your tree onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Platteville. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that USDA zone info for Platteville is not always accurate and the actual date of last frost is different every year. Since half of the time in Platteville last frost occurs after April 15 be ready to cover your tree onions in the event of 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.