One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when it's the best time to plant bunching onions by using the USDA zone info for Hillsborough.

Planting Calendar for Bunching Onions

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

Bunching Onions tend to make it in very little cold which means that you can plant them a bit earlier in the year than more sensitive plants.

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

Last Frost Date

On average the last frost has passed is on April 15 in Hillsborough. It might get as low as 5°F during the coldest months of winter.

Since the USDA zone info for Hillsborough is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Hillsborough there is a last frost after April 15 so make sure that you are prepared to protect your bunching onions in the event of one of those late frosts.

USDA Zone Info for Hillsborough

Here is the info for USDA Zone 7b.

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

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

Plants to Grow in Hillsborough

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