Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of getting a good idea when you can plant spinach is to examine the USDA zone info for Zone 4a.

Planting Calendar for Spinach

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

Since spinach are one of those plants that can tolerate a little bit of cold weather you can plant them a little bit earlier in the year than other frost tender plants.

The earliest that you can plant spinach in Zone 4a 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 spinach and expect a good harvest is probably August. You probably don't want to wait any later than that or else your spinach may not have a chance to grow to maturity. If you are starting your spinach indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Zone 4a. You should expect an average low temperature of -30°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Zone 4a is not always accurate and the actual date of last frost is different every year. Half of the time in Zone 4a it frosts late in the year after May 15 so make sure that you are prepared to cover your spinach if you have one of those late frosts.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.