Evolution Four-LT Shown with optional aluminium capping. If you have a nice wall that gets plenty of sun then this 4ft deep Alton lean-to greenhouse may well be ideal. The wall at the back of a lean-to greenhouse acts as a heat sink- regulating the greenhouse temperature during the day (reducing over heating) and storing the warmth of the day and releasing it during the night helping to keep you plants nice and snug. You can position your sliding door on either end when assembling and this model is a part of the Alton Evolution range so it includes all of the standard features of benefits that have made Evolution models so popular – combining the beauty of wood with the modern practicality of powder coated aluminium. Toughened glass comes as standard as well as good ventilation (louvre side vents plus automatic roof vents), aluminium base (so no cedar touching the floor), guttering and downpipes as well as superb optional staging and shelving. This model comes with cedar capping as standard, however you can choose to upgrade to the maintenance free aluminium capping system which is powder coated in the elegant moss colour which is specifically chosen to blend in well with the greenhouse once it has weathered and turned into its natural silvery-grey colour.