If you are going on a short vacation, the Self Watering Probes will help to keep your plants alive by providing them with a drink of water. Simply place a bowl of water near the plants you are going to water, insert the 33" watering tube in the water, push the ceramic cone into the soil surrounding your plant and water will be slowly emitted through the cone and into the soil. The self watering probes will emit 1/4 to 1 litre of water per week, depending upon how thirsty your plant may be.