Medium choices for indoor/windowsill culture

[DennisH]

Hi, I'm new to the forum and looking forward to learning lots, and maybe someday contributing something myself. I've been growing orchids off and on for many years, but I don't think that I've gotten past the experienced beginner stage; i.e., I've become very proficient at growing orchids (mostly phalaenopsis or oncidium hybrids) that rarely re-bloom or succumb to the period neglect that happens when I have long business trips. I've read a lot, so mostly I know what I'm supposed to do, and I know what my biggest problems are. But there are some things that still perplex me.

I have an opening question. I've read lots of articles on the pros and cons of different potting mediums, many of which are written by professionals who grow orchids in a greenhouse, but I've looked and never found recommendations of which mediums are best suited for the relatively low-humidity of the home windowsill. It seems to me that the a medium that is ideally suited for the greenhouse environment would dry out too quickly in the home. It would be great to see a discussion of how one adapts potting mediums to suit different temperature/humidity regimes.

Thanks,
Dennis H

[Carolla]

Hi! I grow in my home and it is dry here, so maybe I can help a little. I have grown Phals for a long time. They generally have done well for me in coarse bark with some (about 1/4) sphagnum moss mixed in to add some moisture retention. I tend to underwater and they survive my neglect pretty well. When I water them, I often soak them for a time to be sure the bark and moss take up what they can. The seem to like my East windows very well, or under lights in the middle of a large and sunny room. I also tend to use glazed pots with holes in the sides as well as the bottom. The glazing keeps more moisture in, but they have good air exchange at the roots, vital for Phals.

I don't do so well with Oncidiums, too dry, too stagnant or something. My Cattleyas are in my South kitchen window in either med/coarse bark or S/H. I can keep track and keep them pretty well watered there, they are doing well.

I have a couple of Paphs with my Phals, long enough to rebloom one of them, but they are still in their original pot and bark medium (looks like medium bark). I put trays of gravel under them in hopes it will help them. They do need more water than the Phals.

That's a bit of my experience... I hope that helps you! I figure I'm about the same level as you are advanced beginner - years of experience, but not a wide variety of orchids and I've pretty well just done the same things and gave up on the plants that didn't make it.

[ksriramkumar]

Hello and welcome.

There are variety of potting material available and it is best to choose based on your climatic conditions. Many of us don't have a greenhouse and grow on variety of medium in indoors or outside.

low humidity areas would benefit from medium that retains moisture (e.g bark topped with sphagnum moss or semi-hydrophonic medium). Sure other members would chip in with their suggestions.

[78Terp]

Welcome to the Forum.

I live in dry environment here in Littleton Colorado. I use a medium to course bark, perlite, charcoal and coconut husk chunks misture (about 30% coconut husk). Everything I used it on, oncidiums, zygo, phals, paphs to name some, are doing extremely well. The coconut is in place of sphag which I think breaks down too fast compared to the rest of the media.

[DennisH]

Hi Carol, I have come to the conclusion that bark alone is not suitable for the home. It drys out to fast, and until it is decaying it doesn't retain enough moisture. For Phals I will add sphagnum at the top of the pot which help retain moisture, and gives me a quick way to tell when the plant needs to be watered. I pot them in plastic orchid pots or terracotta which I put in a ceramic pot, otherwise they dry out to fast. I'd like to find a good supplement to add to bark that would retain moisture throughout the pot, but something that would last longer than sphagnum. I buy my orchids mostly ---- vendor information removed -see faqs on posting----, and they pot their phals in sphagnum alone, but I don't think that is a good idea. I've never been able to grow cattleyas but ---- vendor information removed -see faqs on posting---- has a wide array of oncidium hybrids that do well in the home, as long as you have good light. I don't at home, but do at my office, so I keep them there.

Thanks for the advice. I suppose lots of materials beside perlite can be used to open the potting mixture to air (e.g., packing peanuts, or just using larger bark). I try to observe them, but I find it difficult to figure out what the relationship is between an issue and its cause. For example, I have orchids that appear to be healthy and are growing well, but they do not re-bloom. Is that a fertilization problem? Low light problem? Temperature problem? I'm afraid that I'm not as diligent as you are. I check my orchids just twice a week.-dennis

[DennisH]

Thanks. I have never used coconut husk, so I'll that a try. I don't like perlite because it looks so unnatural. Is there an alternative you would suggest? Why the charcoal, I though it's purpose was to keep decomposing media from becoming 'toxic', which I would think would be much of a problem with the mix you use in a dry environment?

---------- Post Merged at 08:17 AM ----------

Thanks for the welcome. You have identified my question well, how does one pick the potting material. Most descriptions of potting materials only talk about their intrinsic characteristics, not how they interact with the environment. I suppose that question is too simple, because one has to take other factors, such as the type of pot and the watering regime, and, of course, the needs of the plant.

[78Terp]

Make sure you soak any new mixture overnight before potting with it. Many start with hot water to help it penetrate the bark and for the coconut husk to hydrate well. I think the perlite is to help give the roots breathing room and the horticultural grade charcoal for absorbing 'stuff'.

Observe the orchid and how you care for it and see it you are providing the balance it needs. I have a friend at work who I would never give an orchid to that needs lots of water. A paph would be dead in her care.

But for me, I give them the attention they need, even if it just to check them, everyday to see if they require water. I made the commitment to make the time necessary to care for them when I got into this hobby. And now I have too many to skip out on them. Unless I want to kill them. And so far they seem to like my care and environment provided.