Soil Moisture Meter for Plants, Hygrometer Sensor Water Monitor, Plant Moisture Tester for Indoor Outdoor Garden, Potted Plants, Farm, Lawn, No Battery Needed

Spend $7 on a simple galvanic moisture meter and don't overwater. Don't leave the meter in the soil. Wipe it down and bring it inside each time. Notice that the tip of the meter is a different metal than the shaft with an insulating plastic spacer between them. When placed in moist soil, it acts as an electrolyte creating a super weak battery. The tip starts to corrode, generating just enough current to move the needle. Wetter soil conducts better, so the needle moves further. Example: https://www.amazon.com/Zoiydals-Moisture-Hygrometer-Monitor-Outdoor/dp/B0FPWPMR2C