I often find some of my potted plants have root rot problem. They start dying from below. I was been advised in the past to avoid over watering but even if I maintain that and the soil remains between dry to moist, still root rot occurs. Rather I feel perhaps it happens more if watered less. Usually I have noticed this problem with Pothos, ZZ plant and other indoor plants that are grown in low light. What might be going wrong ? My soil is porous and has a lot of coconut fiber added to it. But still there is problem.
Overwatering is the cause of the majority of indoor plant deaths. This usually goes hand in hand with not enough light. We tend to think if we can see indoors then that is enough to grow a plant. Outdoor light levels are commonly measured at 100,000 lux. Indoor light levels range from 20 to 1000 lux. A reduction in light reduces the amount of plant activity and also reduces the need for water.
This is not easy to visually estimate and gets worse the farther a plant is from the light source. Your plant at the windowsill might get 500 lux on a sunny day. If you decide to move it two meters away the plant now gets one quarter of the original light or about 125 lux thanks to the inverse square law. This is just enough to sustain it.
Another common problem with determining when to water is the tendency to look at the surface of the soil. You will often find that the surface of the soil is dry while an inch down it is still quite moist.
For houseplants in low light levels I recommend:
- re potting in the spring by removing the bottom of the root ball of the plant and adding more soil at the bottom
- rotating your plants to higher light levels for a few months at a time. Move them outdoors in the summer if you can give them time to adjust to the increased light
- fertilise at extremely diluted concentrations only during the summer months. A low light plant cannot use the fertiliser as it is not getting enough light levels to use it
- use a wicking system as described here and here
Root Rots and plant slowly starts dying from bottom
Soil is moist not wet.
I un-potted one such dying plant and inside the soil was a little moist. No stagnant water, no bad smell etc. Friends, I feel my plants are dying because of some problem in the soil. Fungal / bacterial growth may be. But certainly not excess water problem. My snake plants, Sansevieria, are rotting one by one with same kind of problem. For once try to step aside this excess water advise and tell me what can I do with the soil to make sure there is no problem in it. I have been told since months about excess water but I feel when I follow that, my plants shed more yellow leaves because of lack of water than problem due to excess water,. Of course I can not replace all the soil, but is any other way to make sure soil does not has any harmful growth in it ?