Just a quick question

ok so i am wondering if i can use the same soil if the soil already had a plant in it?

You can but it is recommended that you flush the soil out with pH adjusted water and then add the necessary nutrients for growing cannabis/tomato plants which can be found in the organics section of the forum

Yes, but why would you? It has already been robbed of 90% of its nutrients. Container grows extinguish a majority of the nutes after only a few months. Which is why most growers supplement with additional nutes. Not to mention soil is as cheap as dirt! Get new soil if you're serious about growing.

ok thanks i will start using fresh soil from now on.