Finish doing something

Question

I'll have dinner later after I've finished in the garden.

Is that sentence grammatically correct? I have doubts about "finish in the the garden", the verb requires an object, doesn't it?

Answer 1

I'll have dinner later after I've finished in the garden.

is a perfectly correct and normal sounding sentence. It omits the object of the verb. Presumably the listener knows what the speaker is or will be doing in the garden.

One could add an object, if that information is not known:

I'll have dinner later after I've finished weeding in the garden.

I'll have dinner later after I've finished burying the body in the garden.

but that is not required if the object would be redundant information.

Answer 2

The verb to finish doesn't always require a direct object. "I've finished" is a perfectly grammatical sentence. Your sentence is also grammatically correct. It doesn't matter what you're doing in the garden - and it's understood that you're probably doing gardening work in the garden. In any case, your point that you plan to eat dinner after finishing your activities in the garden is understood.