The Kilcher Homestead is a 600 acre Pioneer Homestead that has been protected for perpetuity via a ConservatIon Easement. The Kilcher Family has also preserved the Historic Cabin and site as a LIving Museum.
Yes, negative pH is possible, but not in water as a solvent. The range of pH in water is 0 to 14 (to be more precise, it is -1.7 to 15.7, but for simplicity's sake, we start with the usual values.) Thus, what pH indicates is the ability of the acid to form H3O+, which can then donate a proton.
pH is defined as the negative side of logarithm of the hydrogen ion that is concentrated. The pH scale goes from 1 to 14 with 1 being the most acidic and 14 being the most basic and 7 is neutral. pH can be a huge factor in why your plants may or may not be growing. If you have a high or low pH your plants might grow better or worse. Some plants do prefer more acidic soil and some prefer more basic soil.