Unused rooftop space is perhaps the biggest opportunity we have for creative urban agriculture
What are the biggest challenges for growing on rooftops?
Water consumption – often with full exposure to sun and wind, evaporation and transpiration are significant issues when growing on rooftops. Because of this, water consumption of rooftop gardens can be up to 50% more than gardens in more sheltered areas.
Irrigation – because of the increased water consumption, getting water to the gardens is essential. But if the original builder wasn’t thinking ahead, or even if they were, the source of your water may be challenging, and piping in traditional irrigation system almost impossible.
Drainage/Sequestering – Traditional planters require drainage holes at the bottom to allow water to flow through. This creates a significant mess and challenge for controlling the drainage of that water. It’s also very inefficient. In terms of your garden, that water is wasted, and if captured and sequestered, could be put to a much better use.
SIP gardens solve these challenges by storing water in a hidden reservoir under the soil - allowing that water to wick up evenly over time as the plants need it, creating a self-watering garden.
Water Consumption - By having a consistent water supply, the challenges of full exposure are significantly reduced. Because water comes from the bottom up, evaporation is all but eliminated.
Irrigation - A properly installed SIP garden has a reservoir which holds ~ 7 litres of water per square foot of garden space. This simplifies irrigation requirements, as instead of having to water everyday, you can simply fill up the reservoirs once a week or less. Especially if all you have is a hose, unrolling it once a week is much easier that once or twice a day.
Drainage/Sequestering - This is a huge win for water sustainability, especially in drought prone areas. Because the reservoir is under the soil, it collects excess water and rain, and stores it for later use. When the reservoir is full, the drainage is controlled and exits the OverFlow. This allows you to limit water waste, and direct overflow wherever you want.