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.

In Olean you can estimate when it's a good idea to plant tree onions by reviewing the USDA zone info.

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 just a tiny bit earlier in the year because they do ok in moderate cold.

The earliest that you can plant tree onions in Olean 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. You probably don't want to wait any later than that or else 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 few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Olean. In the coldest months of winter you can expect an average low temperature of -20°F.

Keep in mind that USDA zone info for Olean is just an average and the actual date of last frost is different every year. Since half of the time in Olean there is a last frost after April 15 be ready to cover your tree onions in the event of one of those late frosts.

USDA Zone Info for Olean

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 Olean

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