Reuse potting mix?

I have removed a 3 foot tall corn plant from a pot. Can I reuse the potting mix to plant other vegetable?

 

I see no reason why not !

 

Does it matter the some corn roots stays in the soil?

 

no, they will decompose over time.

 

I always reuse the soil.

 

When I repot my houseplants, I reuse a little bit of the soil but I always make sure to add mostly fresh compost/soil.
The older soil will be lacking nutrients.

 

I've started re using compost from the containers because last year i couldn't get new because everyone was growing veg for the first time, because of the first lockdown,got to be careful that there's no vine weevill in it though.
Also add some extra fertiliser.