This is my first year using Eartbox, but a little wider and longer would be nice. Some plants like zucchini can realy dominate the box. It could be a issue of scale, might require a second tunnel for water wicking on the far side. If your handy it would be possible to build a larger box as a test, there are YouTube videos on building an Earthbox. However, they were close in size to the original and with the cost to build and time may not be worth the effort.