The Bottle-Top Watering Spike® with the 'Aqua Balance' Adjustable Dripper is the worlds only fully automatic watering system controlled by the weather, or room conditions. It works indoors, outdoors, in the greenhouse or in your conservatory. Simply adjust the Dripper, screw it onto a partly filled plastic drinks bottle (250ml - 2litres), invert the bottle, squeeze it (to clear airlocks), and then put into the prepositioned Spike. When the water/air in your bottle reaches ambient temperature & pressure, your Watering Spike® will automatically supply measured amounts of water to your plants - The warmer it is the faster it drips, the cooler the weather the slower it drips!