Like every other Palram product I've bought, these come in a zillion pieces, but at least assembly with these was incredibly easy...hanging them, however, is another story. I suppose it depends on which greenhouse kit you have, but mine has the angled roof supports every other panel, which limits the height and number of these you can put in each column and if you put one next to another, it's like solving one of those brain challenge puzzles to get them level and hung correctly, especially when close to those angle supports. I have a run of 4 in a row and I found that more difficult to accomplish than building the entire greenhouse. They are, however very sturdy and seem to support a good deal of weight without problem. A far better value I feel than the plastic shelves, but I suspect most greenhouses will need a mix of both to maximize shelving options.