Take the guesswork out of properly watering your plants with the Rapitest Moisture Meter. The moisture meter tests moisture levels at the roots. You will no longer run the risk of over watering because the soil near the surface is dry, or under watering because the soil appears moist. The Rapitest Moisture Meter is extremely easy to use. You simply insert the corrosion resistant probe into the soil and watch the needle on the meter. Includes a list of needs for over 150 plants.