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

A way of figuring out when it's the best time to plant tree onions is to look at the USDA zone info for Marlborough.

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.

You can plant tree onions slightly earlier in the year because they are one of those plants that can tolerate a tiny bit of cold weather.

The earliest that you can plant tree onions in Marlborough 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. If you wait any later than that and your tree onions may not have a chance to really do well. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Marlborough the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that USDA zone info for Marlborough is just an average and the actual date of last frost will vary from year to year. Since half of the time in Marlborough there is a last frost after April 15 be ready to protect your tree onions if you have a late frost.

USDA Zone Info for Marlborough

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Marlborough

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