One of the first steps you take when you are determining your gardening schedule is find your 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.

The first opportunity to plant rhubarb in Zone 1a can be estimated by looking at the USDA zone info.

Planting Calendar for Rhubarb

Frost tolerance for rhubarb:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Rhubarb do well in moderate cold which tells us that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant rhubarb in Zone 1a is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant rhubarb and expect a good harvest is probably July. If you wait any later than that and your rhubarb may not have a chance to fully mature. You can get started a few weeks earlier by starting your rhubarb indoors.

Last Frost Date

On average the last frost is on June 15 in Zone 1a. It might get as low as -60°F during the coldest months of winter.

It's important to 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 Zone 1a and it is different every year. Since half of the time in Zone 1a it frosts late in the year after June 15 be ready to cover your rhubarb if you have one of those late frosts.

USDA Zone Info for Zone 1a

Here is the info for USDA Zone 1a.

Average Date of Last Frost (spring)	June 15
Average Date of First Frost (fall)	July 15
Lowest Expected Low	-60°F
Highest Expected Low	-55°F

This means that on a really cold year, the coldest it will get is -60°F. On most years you should be prepared to experience lows near -55°F.

Plants to Grow in Zone 1a

You may be interested in your other planting guides for Zone 1a.