Hi chaps, back issues (that’s problems with my back not old copies of magazines) have forced me to get some troughs, I will be putting legs on these, they are 100x40cm but they’re 30cm deep, I intend to grow salads and stuff so nothing deep rooted and it would cost a lot to fill with compost, anyone any ideas to, maybe, half fill the depth .... old cardboard boxes flattened sprang to mind !