City dwellers wishing to grow fresh vegetables and flowers sometimes opt to plant gardens on the rooftops of homes, apartment complexes and commercial office buildings. While some roof gardens produce healthy foods and flowers with minimal problems, others experience difficulties.
Buildings requiring a lot of water for general maintenance may pose problems as roof gardens significantly cut into the water supply. Since soil is a relatively heavy substance, most roofs require reinforcements before gardens can safely be sown on their surfaces. Roofs regularly subjected to high winds may lose significant numbers of plants and seedlings during certain seasons.
Although roof gardens need a protective membrane in between the soil and the rooftop, leakage may occur if nails, screws or garden tools penetrate the covering. Since repair of the membrane necessitates removal of part or all of the garden, this is a costly renovation.
Unlike a typical garden, roof gardens require intricate and costly drainage systems to ensure no water seeps into the building through tiny cracks and crevices in walls or drips down the sides of the building. Insurance premiums for buildings with roof gardens are generally higher than for standard structures.