I agree with Josh. Be very careful about your soil mixtures and excess water in the soil.
I am known to "write excessively" so if this bores you or anyone else, please just skip to the end right now. However I listed some important information on variegated plants I suspect you will want to read since most folks just don't understand the structure and processes of these plants.
I just don't know how to explain things without explaining enough so a grower understands both the concept and the background provided by science. You can find some very good discussions on this forum about soil so if this is useless, please try to find a few of them now, mostly written by Al Tapla.
Once anyone understands how a rainforest functions, how the soil in the rainforest is composed and how different it often is from the bagged "mud" we buy in a garden supply center, how often it actually rains and how individual specimens tolerate and utilize so much water, along with the role humidity plays in making plants prosper and the survival techniques employed by the many species, only then do we grow them successfully.
There is a natural balance in the forest between air, heat, humidity and water and most home growers don't understand the process, nor believe it can be duplicated in a home.
If you could visit a rainforest you would quickly learn the soil is composed of leaf litter, decaying wood, compost and the charcoal left behind when a part of the forest burns. If we'll just listen to Mother Nature we can all make our plants grow as they should in nature. In the forest a great deal of litter falls to the ground where it is broken down through natural decomposition via earthworms, insects and fungi. . The shallow roots of very large trees then rapidly absorb almost all of this organic matter. Although many of us grow our plants in air-conditioned living rooms where there is little humidity, in the forest the heat and humidity encourage the further decomposition of the rainforest leaf litter. That does not mean you cannot continue to reuse plant material refuse and create your own compost for future use with your own plants. In a natural rainforest the frequent rainfall that washes away many nutrients to leave the soil infertile and acidic leaches out the majority of the nutrients that manage to be absorbed into the soil. It is not uncommon for very large trees to fall in a storm but all the seedlings waiting for the patch of light that is left when a giant falls quickly replace them. Neither space nor light is wasted in the forest!
Tropical plants need light and have developed some very unique ways of finding it. Home growers tend to starve their plants for light and I will touch on that subject. In almost any rainforest, light is a very precious commodity! Plants fight for position and large ones often deprive small specimens of any light at all! Anthurium, Philodendron and other species climb trees to reach the light! As they grow high on the side of the tree they morph into what often appears to be a totally different species! Although a few, mostly with velvet-textured leaves prefer lower light, most tropical plants prefer bright indirect light. Some will exist in deep shade like your living room but will often not flourish. Filtered, relatively strong light is best in most cases. The light coming through a window is much stronger than the light from an inflorescent tube. Your plant will reward you with a dramatic change in the production of inflorescences and leaf shape if you give it what it craves!
The topsoil layers of a rainforest may be only one to two inches deep (often less) and provides only a limited amount of nutrition to the plants. Still, the plant life is lush since the plants store the nutrients inside their own cells as well as produce sugars via photosynthesis rather than gathering a great deal of their food from the soil. Were you to step into a living rainforest you will find far more varied plants dangling from the trees than you will ever find growing in the soil. Even in the trees, plants in the forest have adapted to utilize the falling nutrients from their "brethren" in order to flourish themselves and survive. When plants decay, others rapidly absorb the nutrients left behind from the dead vegetative matter and reuse them all.
Despite the belief of far too many growers, successfully growing tropical species, especially aroids, is not just about when and how much you water a plant, it is far more about the content of the soil�s moisture! Some aroids grow well in wet soil; others need a period of dryness! In most cases the water quantity is instead about how fast the water flows through the soil that can cause a lack of oxygen to the roots of our plants. We must learn how to control and preferably eliminate anerobic fermentation and saprophytes that can quickly turn into pathogens that are capable of killing our specimens.
Have you ever picked up a pot and were suddenly aware of the strong odor of death? That odor is due to the growth of saprophytes. Saprophytes are organisms including fungus or bacteria that grow on and draw nourishment, often saprophytes utilize dead or decaying organic matter, matter including soggy wet mud-like soil. They are bacteria proficient at the breakdown of the bodies of dead plants and animals returning the organic materials to the food chain. Saprophytic bacteria are usually non-pathogenic but may also contain the pathogens that attack the roots of our plants and cause them to rot. The advice to "slow down on the water" is really about how to control these pathogens. Fermentation often occurs in muddy soil that will not allow the roots of your specimen to breathe along with the uptake of fresh oxygen. However, fermentation does not necessarily occur in clean water, which is why we can cause a plant that is about to die to grow new roots if kept in a clean glass of water.
It is necessary to use soil mixes in both your pots that can allow the roots to freely draw in fresh oxygen and will not remain compacted or soggy. The reason plants rot is not entirely as a result of the amount of water given to the plant but can often be due to the structure and content of the soil! These are rainforest plants and many other plants are literally drowned for months at a time during the rainy season and flowing rivers flood and rise!
In order to duplicate Mother Nature as best possible we use a basic mixture on the advice of Emily Colletti, Horticulturist of the Research/Aroid Collection at the Missouri Botanical Garden in St. Louis, Missouri. Many of our specimens have reached or are beginning to reach their adult size and have produced inflorescences for sexual reproduction. The goal of this mix is to allow the roots to freely find places to stretch and extend without
constantly finding soggy soil where they may eventually contact fermentation and rot. If mixed well, this mix will remain damp but still drain quickly.
This is a basic mix and can be modified (often should be based on the plant). Our basic mix is about 30% good potting soil, 30% high quality peat moss, 20% orchid potting media that has hard and soft woods, charcoal and a small amount of gravel and/or sand mixed with approximately 10% Perlite�. All that is combined and mixed thoroughly with a few handfuls or two of cedar mulch along with finely cut spahgnum moss. The purpose to include charcoal is to increase drainage but also to take advantage of the tiny air spaces in the charcoal for growing beneficial microbes. All of these combined help with water retention and oxygen content in the soil. If you are composting your own dead vegetation and have some good compost, feel free to add it. Small pieces of granulated charcoal plus most of the other needed supplies can be purchased from any good orchid supply store.
Depending on the species, we sometimes also add small pieces of crushed volcanic rock, also frequently sold in orchid supply stores.
The exact mixture is not critical but all of these ingredients should be mixed as thoroughly as possible. You will notice the total does not add up to 100% since I will throw in whatever is needed to make the soil right for he plant. I certainly recommend more organic material rather than more soil if this is confusing.
Some important info on variegation most don't understand:
Since you collect variegated plants (commonly called "variegata" by growers) you may already know all of this but since many people read these posts and don't always understand the nature of the discussion I felt it important to make these things known about variegation. Excess variegation can be the cause of the plant's death and completely white (those that have no chlorophyll) plants rarely if ever survive.
Variegation is a phenomenon observed in some plants where partially or irregularly colored patches or streaks of different colored tissues in a variety plant organs are observed, normally on a leaf or stem but sometimes on a flower. Variegation may the result of natural DNA characteristics, the suppression of normal pigment development, pathogenic infection (particularly a viral infection known as Colour Break Virus) but may also be a mineral deficiency or genetic differences within the plant's cellular structure as a result of mutation. The virus is a somatic (cellular) mutation induced in tissue culture.
Similar mutations are being generated in tissue culture around the globe with Spathiphyllum, Homalomena, and Philodendron and other plants that usually involve the introduction of a benign colour-breaking virus in the lab. Variegation is sometimes seen in nature in species such as Epipremnum aureum (commonly called Pothos) and some Dieffenbachia as well as other species. It is now common for tissue culture laboratories to deliberately expose plants to the Colour Break Virus in order to chemically induce variegated specimens that may be sold at a higher retail price. Chimeral variegation as well as viral variegation (Color Break Virus) are unstable and temporary since they are not passed along through seeds and often vanish in a generation or two. Plants that are excessively variegated and lack sufficient chlorophyll (green tissue) are often incapable of survival due to the lack of an ability to conduct photosynthesis.
A chimera (KEE-mer-a) is a plant or part of a plant such as a leaf blade that is composed of layers that are genetically different and whose apical meristem is composed of two different types of tissues, one pigmented and one not pigmented. The most common form is a variegated plant where the leaf may be partially white or yellowish as a result of a lack of the ability to synthesize chlorophyll. These white and yellow patterns are caused by tissues without chlorophyll or other plant pigments. This is normally due to defective tissue formed without pigments since the meristem that produced them lacks cells containing pigments. This kind of chimaral variegation is not stable and morphs as the plant grows. Many popular foliage plants including some commonly available aroids are chimeras and many are artificially created in tissue culture laboratories rather than by nature via the introduction of the Colour Break Virus which inhibits the growth of chlorophyll in parts of the plant including the leaf, stem and petiole. The Colour Break virus is often unstable and in many cases the variegation fades in time. Chimeras are also commonly seen in nature but neither chimeral variegation nor viral variegation is commonly passed along through seeds
Now, just a word on photosynthesis since you asked if light was the problem you are seeing. In green plants and some other organisms including algae and specialized bacteria, photosynthesis is a chemical reaction caused by the interaction of chlorophyll within the plant and the sun's light combined with carbon dioxide, inorganic salts and water to produce carbohydrates. In green plants the autotrophic process converts physical energy from sun light into carbohydrates in the form of sugars. The biological term reduction indicates the hydrogen is molecularly stripped away from the oxygen. These sugars are produced for the purpose of providing energy and food to the plant, thus growth. Most forms of photosynthesis release oxygen to the atmosphere as a byproduct. Plants don't manufacture oxygen, they just release it by using the hydrogen in water.
Autotrophs create their own food by utilizing photosynthesis. The process is completed through the reduction of carbon dioxide by adding hydrogen in water (H2O) to create organic compounds. In green plants an autotroph converts physical energy from sun light into carbohydrates in the form of sugars In biology the term reduction indicates the hydrogen is molecularly stripped away from the oxygen. They may also form chemical energy by synthesizing complex organic compounds from simple inorganic materials in order to produce fats and proteins from light. The process is also known as being autotrophic.
I hope this is helpful but I do understand when many home growers feel I have just wasted their time. You can take a look at the photos on the link below and get an idea how all this works for us.
Steve
www.ExoticRainforest.com
PS: I hope all this was not too boring!
Here is a link that might be useful: Our little plant collection
Q