One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Dover you will be able to estimate when it's possible to 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.

Tree onions do ok in moderate cold which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant tree onions in Dover 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. Any later than that and your tree onions may not have a chance to really do well. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

In Dover 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.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Dover and it will vary from year to year. Half of the time in Dover there is a last frost after April 15 so always be ready to cover your tree onions in the event of a surprise late frost.

USDA Zone Info for Dover

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 Dover

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