Last year, Lego introduced plant-based plants, bricks that are made of sugar cane. While producing from oil costs CO2, the sugar cane absorbs CO2. According to the Danish toy production company it is a step in Lego's plan to make every brick from sustainable material by 2030. Check out this unboxing video to see what it is all about.
Now go ahead and fill that greenhouse that you built. Just make sure you don't step on them...