Flesh color is white. Ontario is highly scab resistant and has some resistance to late blight and Fusarium wilt. It has some tolerance to harvest bruising. It sets and sizes tubers late and maturity may be too late for regions with a short growing season. Vines are difficult to top kill.
Tubers are susceptible to after-cooking darkening, particularly with late storage.
The variety tends to produce tubers in chains when subjected to heat and moisture stress.