One of the first steps you take when you are figuring out 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.

The USDA zone info for Ripon can be read to figure out when you can plant tree onions.

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.

Since tree onions are barely cold tolerant you can plant them slightly earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tree onions in Ripon 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. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Ripon 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 Ripon may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Ripon last frost occurs after April 15 be ready to protect your tree onions in the event of one of those late frosts.

USDA Zone Info for Ripon

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 Ripon

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