Hydrofarm Jump Start Digital Plant Heat Mat Temperature Control. This water-resistant temperature controller comes with a stainless steel temperature probe, ensuring constant optimum temperatures for specific crops and controlling temperature in colder or warmer environments. The controllable range is from 68-108 degrees Fahrenheit, with Celsius or Fahrenheit readout. Simply press the up or down button to change the temperature. It has a maximum current of 8.3A and a wattage of 1000W.