They claim "68 times more than required to operate the sensors", then mention a sensor to measure soil moisture.
A basic soil moisture sensor, like say, the ones I have stacked on a shelf here, will work on 2 AA batteries. It runs on 2V at 10mA. So that's 20 milliWatts, and in willing to be a fair bit of that goes into the electronics that make a red, green or orange led light up at certain moisture levels, and the bit that beeps when below a certain level.
Still, this sets something of an upper limit at 1.3W, or maybe 680 mA? Those seem rather high, so I'm betting their moisture sensor is a bit more delicate than my model. It depends on the size and number of cells though.