Before you purchase your window flower box first measure the window-sill that you are going to fit under. The flower box should be filling with compost leaving 2cm 2.5cm gap at the top of the window trough. Before you plant your plants in the window box planter, arrange the plant while they are still in the pots, remember not to place plants to closely together allowing the plants room to tiller, trailing bedding plants should be planted at the front of the window basket. When happy with your display plant your plants into the compost filling all areas with compost and then compact down and water. Remember to always keep the wall trough watered daily.