Planting on green areas?

[fuzz]

Is it possible to plant on the green areas of the forest farm?

Spent the winter building a sweet walled sprinkler system sw of the house, but now it's spring and I can't hoe scythe chop or mine it to plant seeds...

Is this a bug? Or intentional, or am I missing something obvious?

[I Kinda Fail]

Can't plant on grass, only the yellow soil