The water bump shall pump water via ( a tube) from a measuring cistern into a styrofoam box when its below a threshold level of "dryness". A piece of damped cotton wool is used to simulated a closed circuit when a closed circuit is formed. The indication of "H" means that the measure value is high, which is above the threshold set in the code ( logic comparator). "H" stipulate that the soil is wet. When the moisture picks up data and compares with the threshold, if higher than threshold, a "H" is displayed on the microbit LED, else it would display "L", which its dry ( remove the wet cotton wool). When the condition is wet (H), the water pump is turn off, else the water pump turns on and pump water , when condition is low (L).

Soil Moisture Sensor
Microbit
Water Pump with tube
Expansion Board (Keyestudio)
Power Module