Prohibition of entry
3. (1) Entry on premises may be prohibited by notice to that effect and entry is prohibited without any notice on premises,
(a) that is a garden, field or other land that is under cultivation, including a lawn, orchard, vineyard and premises on which trees have been planted and have not attained an average height of more than two metres and woodlots on land used primarily for agricultural purposes; or
(b) that is enclosed in a manner that indicates the occupier’s intention to keep persons off the premises or to keep animals on the premises. R.S.O. 1990, c. T.21, s. 3 (1).
https://www.ontario.ca/laws/statute/90t21