Root Rot What causes root rot? Low Oxygen levels. (DO) Dissolved Oxygen. Temp's are the main reason for root rot, Low temps will lower the DO levels and high temps will cause low DO levels. Keeping temps between 65 to 72 will allow MAX DO levels or max O2 for roots. Over watering also causes root rot, Root Rot infects parts of the roots, which then spread infecting the whole root system causing death, Root Rot can be caused by to high of temps in hydro as well as over watering in soil. Not enough drainage in your soil can cause Root Rot, even signs of it looking over watered, because the soil holds moisture too long for the roots to dry out. Once you find out you have root rot, depending on how bad the problem is, you can add H202 (Hydrogen Peroxide) with your water or hydro setup to kill the bacteria caused from root rot. If the plant is severely taken over by it, there are only a few things you can do, cut off the roots affected by it depending on if its hair roots or tap roots, use H202 mixed with water in a different bucket and use it for a dip to help kill off bacteria before putting it back in the system, also note the system needs to be cleaned out if you have root rot. Using products like SM90 will kill off the root rot, using H202 in your system does more harm than good, it kills off the bad bacteria and good - thus creating a worse problem after the H202 has been added. H202 if used in a hydro/aero system must be replaced everyday due to it dissipating from evaporation. After it dissipates the plants defensive system has been killed off by the H202. Causing the root rot that was not killed by the H202 to re grow and thus overruns the plants root system. So again H202 should never be used in the hydro system/be kept in the system, although it is safe to use to rid of algae growth in rockwool and other mediums, but never be used in with the root zones regularly. SM90 is a good product you can use to kill off root rot. Hydroguard helps protect and there are many other products that work as well, hydroguard is one of the more popular ones that work. To prevent Root Rot, adding product's like Thrive Alive B-1, Sea Weed, Super thrive will help protect your plant's from root rot and will help cure root problems.