Hi! I have numerous potted plants in my apartment, however two of them (a Christmas Cactus and a Peace Lily plant) are acquiring mold on the top soil of the pot. I am not sure why: I do not over-water them and they are both in good soil. The Christmas Cactus' pot does not have draining holes, but even the smallest amount of water will cause the top to mold. The Peace Lily plant has drainage holes and is near a window, but also seems to mold at the top. I haven't watered either plants in almost a month because the soil is still wet. Any advice would be incredibly helpful!! Sincerely, Lauren
The Christmas cactus (Zygocactus) is native to Brazil and lives on the branches of a tree. With no drainage holes the soil has to be soggy near the bottom. Put your fingers in as far as they will go and see if is soggy wet. If so, you need to get it into a porous soil mix like a cactus mix. These are rain forest plants and love to be damp but there roots will not tolerate excess moisture. That means a pot with drain holes. These plants don't live in soil in nature. http://www.exoticrainforest.com/zygocactus.html Sounds as though you have a similar problem with the Spathiphyllum (Peace Lily). These plants actually live in full sun or very bright light as well as along the edges of a stream or in the water in South and Central America. They are members of the plant family Araceae (aroids) and must have fast draining soil. There are a number of forms you can mix yourself. Some folks prefer about 50% orchid bark with the balance a mixture of a good potting soil, Perlite, some aquarium charcoal and some peat moss (about an equal mixture). I prefer 40% potting soil, 30% peat moss, and the balance a roughly equal mix of charcoal, orchid bark, peat moss and compost. The mix is not critical. These plants can also be grown in nothing but water and we have a fair number that live in a planted aquarium under very bright light. There are many "myths" on the internet about Spathyphyllum plants but they don't like dim light and dry conditions. They will "tolerate" those conditions, but they don't like it. They are also "fertilizer hogs" (a direct quote from the world's top aroid botanist, Dr. Tom Croat at the Missouri Botanical Gardens in St. Louis). If you allow the roots to stay in soggy soil (and your soil sounds soggy) they will eventually rot. However, it is not the water that causes the roots to rot, it is the mucky soil. All the plants across the back of this aquarium are Peace Lilies. At the time this photo was taken there were one and one half dozen inflorescences on the plants in a variety of sizes. They really do love water, they just hate muck since the muck has saprophytes that kill the roots. Well, I tried to add a photo but the system won't accept it! You can see several on this page: http://www.exoticrainforest.com/Spathiphyllum Clevelandii pc.htm
Thank you so much for your help. I am excited to buy the various potting materials for the Peace Lily. It's amazing that it has lasted as long as it has, I don't think I've watered it since Christmas! As for the Christmas Cactus, I stuck my finger in the soil, and all of it is dry, but still moldy on the top. It is also in cactus soil. Is the problem that I need to buy a pot with drainage holes? Would cactus soil still be the appropriate mixture to put in the pot? It has also held up surprisingly well considering that I have been hesitant to water it due to the mold. Also, I have noticed some small, black gnats (or so they look like) around my plants. Do you have any suggestions for something that will kill them? There aren't many, as I have been spraying them with a basic pest spray. One last question: Do you have any plant suggestions that do well potted in my hot and humid Alabama climate? I live in an apartment, and struggle to find plants that do well potted both inside and out. Outside I have an elephant ear, hibiscus, aloe, jade, kalanchoe, and ferns - but am always searching for something striking opposed to the standard impatiens and petunias. It is difficult finding plants that can both tolerate extreme heat and a large amount of rain! Any suggestions would be greatly appreciated.
Many Philodendron species will do fine in your apartment. Some of the larger ones will outgrow the pace quickly but if you visit my website and go to the list of Philodendron species in the "collection" you can see photos of quite a few. Many hybrids are also available for sale on eBay and at garden stores. You certainly need a pot that will drain. You might try adding just a small amount of peat moss to your cactus mix to hold additional moisture Some orchid bark will do no harm either since the plant can then begin to attach roots to the bark as it would in nature. When they produce an inflorescence ("flower") these species commonly produce a pheromone (perfume-like substance) to attract a pollinator. If it isn't blooming now I really don't have any idea what suggestions to offer. Others may have better ideas! www.ExoticRainforest.com Steve
