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.

In Waterloo you can estimate when you can plant oregano by referring to the USDA zone info.

Planting Calendar for Oregano

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

Oregano tend to make it in mild cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant oregano in Waterloo is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant oregano and expect a good harvest is probably September. You probably don't want to wait any later than that or else your oregano may not have a chance to grow to maturity. If you are starting your oregano indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Waterloo the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Waterloo is an average the actual date of last frost is different every year. Half of the time in Waterloo you get surprised by a frost after April 15 so make sure that you are prepared to cover your oregano in the event of one of those late frosts.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Waterloo

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