Do I need more light?

You need at least 30w per square feet and your light is providing more than that so it is ok

Not necessarily.. Depending how big u intend to grow plant1.. U will only get a maximum yield out of any 1 light(in optimum conditions)..u can have 1 plant or ten plants and u will get roughly same quality and quantity (in optimums).. The more light =more heat which u will need to consider.. More heat =more ur plant(s) will transpire and drink(not necessarily a gud thing)..if u want to put plant2 in id do it soon b4 plant1 takes over tent!!..gud luck n stay safe.. 👍

Hi @AlanTitchmarsh If your Led really is 300W it is enough to grow 2 plants well. You don't need to add any more light. good luck mate👍