First, double check the settings you have set for your zone. In particular, watering times are very sensitive to the water application rate, which is a function of your selected emitter type. Setting drip when you have rotors will result in severe overwatering. Similarly, setting rotors when you have drip will result in underwatering.
The primary advantage of Smart Watering is that we can adjust your watering schedule daily according to the weather. We attempt to determine a “baseline” watering time based on your location, plant type, and emitter type, but we must make assumptions about your garden, such as plant maturity, soil type, grade, shade, and emitter spacing. Because of this, our initial baseline is just an estimate of the correct watering time.
If you have a good sense of the watering time that is appropriate for your garden, please use the zone adjustment slider so that the typical day shown matches what you are comfortable with. Smart Watering will continue to adjust watering times by weather conditions, but we will do so relative to your baseline. Over time, if you feel like you are still getting too much or too little water, feel free to make further adjustments.
We will constantly refine our watering model with more detailed information, but we seek to strike a balance between accuracy and simplicity. We want to provide a convenient system for everyone, even though most gardeners do not know their soil type and will not measure the grade of their garden, etc. We also know that watering times are ultimately a matter of user preference. For example, some gardeners intentionally underwater because their goal is not maximal growth, but just keeping their plants green. Recognizing that many unknowns and user preferences will always be present, Gro will always provide the means to manually adjust watering times.