March 30, 2011

My Potted Plants are Dying ! Now What ?

If you have ever grown more than a few potted plants at one time, you will have experienced the drama of seeing your plants fail. This is usually accompanied by dropping leaves, wilted stems, and occasionally some seriously bad odors. There are myriad reasons why plants fail, but in the vast majority of cases, the problem is your fault. There are innumerable reasons why plant failure is your fault, too many to list, but let's make sure you realize the problems had to do with you, and I'll list some of the main reasons why.

  1. Hands down, the major reason for plant failure is improper watering. There is an old sage about killing plants with too much water, but this is a misnomer. "Improper" watering is more accurate, since a common scenario is to see a plant wilting due to drought, then water it too much, causing a root rot. The question would then be: did the plant die of too little, or too much water ? The answer would be"both". 
  2. One of the most frequent reasons for plant failure is a poorly chosen potting mix, or a soil medium that has decomposed. In either case, the roots of a plant are suffocating, and the plant will look weak, dried out, and "tired". 
  3. It is also common that people will place an indoor plant into a pot that has no drainage hole in it. This is a great way to suffocate a plant if you over-water the plant. I have seen plants in interior plantings that were literally floating in water due to a kind hearted person who kept watering a failing plant, thinking it was thirsty. If you do use a sealed container, plan to place drainage material in the bottom of the pot, such as broken pot chips, gravel, styrofoam peanuts, hardwood charcoal, or a similar inert material to prevent the plant's roots from sitting in wet soil at the bottom of the pot. Plan for about 1/3 of the height of the pot to be used as drainage. 

Once you discern that the plant is failing, then you need to figure out how to repair it. This is usually  a matter of repotting the plant into fresh soil, removing the dying plant parts, and renovating your growing methods to avoid a recurrence of the problem. If you repot plants every year when the plants start to grow, you'll find that the problems of poor quality soil, rotted roots, and slow growth usually go away. In the case of orchids and bromeliads, annual repotting is a must. In these cases, removing dead roots and repotting into fresh media is key to their survival. Especially in areas with municipal water or well water, the buildup of fertilizer and calcium salts is profound, and will lead to plant failure.

One critical thing to remember is that root rots are caused by a group of fungi called water molds, and are treated with systemic fungicides specific to root rots. The vast majority of fungicides available at retail vendors are for leafspotting  fungi such as black spot or anthracnose. The difference between leaf spotting fungi and root rots is the difference between acne and smallpox; the treatments and cures are quite different ! 

The moral of this story is to watch your plants carefully. If the plants are indoors, they will need watering differently than those that are outdoors exposed to wind, heat and sunlight. Even in near-perfect ouitdoor conditions, plant roots are still confined or imprisoned in a pot, and not allowed to grow out into the drainage of native soil. Keep this "root prison" concept in mind when you decide to overfertilize and overwater. The concept is a good one, especially for those plants used to growing on trees and rocks in their native habitat !

Craig Morell
Pinecrest Gardens        

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