Seed propagation can reveal itself to be difficult if optimal conditions are not present. One common problem is the damping of the seedling. It is often called as root rot. How do you know if your seedling are affected ? Well it's pretty tricky. Almost 100% of the time you realize too late that your seedlings are affected. Seeds will die in soil without germinating or seedlings will die overnight, they will be rotten at the base/soil line and the rest of the seedling will be laying against the soil. The damping off disease is caused by a fungi. Fungi being the scientific name for mushroom. At least four different fungal elements are known to cause the suddent death. It could be initaially present in the soil used to sow the seeds, or be in the seeds itself. Seedlings can be affected in their first 4 weeks of living. Bad conditions are known to trigger this fungi activity. First, overwatering will cause the shrooms to develop themselves and accelerate the rot of the seedling stem. Unsterile soil or dirty growing containers will cause damping.  The best way to prevent damping of your seeds/seedlings is to adopt a clean method of propagation. First, ensure that you use clean container ans sterile soil. You can also prevent damping by keeping your pot or seed tray clean. Preparing seeds correctly for germination is solving half the problem from the start.  Not overwatering is another method to prevent fungal disease. First, before each watering, you can check the soil to make sure it is dry enough. Letting the soil be on the dry side, but still moist between each watering is the best method to prevent damping.  Planting seeds too deep will also encourage productions of fungi or the activtion of the inner fungi elements. Seeds need to feel the heat of the light/sun.  Lastly, having good air circulation will help prevent damping, as it will help the seedling breath and the soil to dry out.  To be on the safe side, you can used different chemical products, such as damping-off, but the best way is to give your seeds/seedlings the best natural treatment.