I decided to do a post on Plythium Mold as its one of the most prominent disease causing fungi. I will cover the disease caused by this fungi and its remedies as well. Problem: Plythium Mold resides in your reservoir, this is the most important thing to know about the infection. The mold causes a disease called Necrosis (stem rot). Necrosis will eat away at the base of your stem and cause it to fall over, obviously ending in death. At first it will look nothing more than a brown spot at the base of the stem. After a few days the plants will start leaning as shown in the picture even though the rest of the plant looks relatively healthy. In another day or so the brown spot will take up a nice chunk of the bottom of the stem, and the plant will be laying down almost completely. Necrosis can affect any plant of any age, BUT younger and weaker plants are most susceptable. It is unfortunate that many people (especially new growers like me) were unaware of Plythium Mold leading to Necrosis before it's too late, their sprout is dead, and they didn't know what hit them. Necrosis caused by Plythium Mold on one of my week old sprouts: If your plant starts imitating this one, look for Necrosis spots immediately! Solution: Long Term - One needs to get the mold out of their a.s.a.p. with a hydrogen peroxide solution. 1tsp per bottle of water for a foliar spray of 3% hO2O2 (hydrogen peroxide) works well as a dillution. I do not recommend however putting more than a TSP or so of a hO2O2 DILLUTED SOLUTION into your reservoir if you are growing hydroponically due to fragile roots. Instead I recommend a product called hygrozyme. It is a root enzyme that encourages the digestion of dead roots. 1 TSP/gallon of water weekly. I have been told it works well with Voodoo Juice, a root growth hormone of sorts. If growing hydroponically take your plants out and clean your reservoir with bleach rinsing very well. Doing this before and/or after an HO2O2 dilluted solution will more than likely kill your mildew problem. Also try running hydrogen peroxide through any airstones in the res if you had them. Short Term - If one discovers Necrosis spots gently scrape some of the brown stem off, put some baking soda on your fingers and cover the spot very gently. This should take care of the spot if its not too late. In Conclusion: It is very important to note that Necrosis is a biproduct of mold, therefore one should keep a keen eye on the look out for mold way before Necrosis ever shows up. If done right, Necrosis nor Plythium Mold will show up. Simple things to do to avoid an outbreak before you even start growing: Air circulation is the most key fundamental. If air is let to sit around and become too moist mold will undoubtedly grow on anyone's plants, so get some fans! But as I stated before, younger and weaker plants are most susceptible. A simple mold outbreak is much simpler to remedy than Necrosis further down the road, so make sure you're on the look out! There are theories that mold is encouraged to grow by too alkaline of a pH, such as in rockwool that was not pHed prior. In conclusion it may be possible to avoid an outbreak by simply pHing your rockwool prior to planting. Happy Growing -Droogy