Is it ethical to kill plant life while gardening?

I live in Denmark and here we have gotten an amazing concept called "City Gardens". Its basically a 3 x 3 meter garden in the middle of the city granting city dwellers acces to grow their own vegetables, flowers etc. Yesterday i got one of these gardens (see picture below). I thought about cleaning it up and plant some new stuff in it but then i saw that there were many small plants and flowers growing in it already. I do know that the first precept is not broken since it covers life that has a breath and a consciousness. But i was wondering if im breaking any other buddhist ethics or precepts by interfering with that plant life already living there? Help would be much appreciated. Thank you. Lanka