Can Orchiata bark with lava rock replace sphagnum moss?

orchidnickJuly 16, 2014

If you have followed my posts, you'll recognize that I do not need to repot any of the usual suspects. All of my Cattleya, Encyclias, Oncidiums, Dendrobiums and all other plants growing outside are either in the 'Pot in a Pot' technique, large rock or bare-root. Without going into great details, the bane of my existence are plants growing in sphagnum moss.

I have many Masdevallias, Pleurothallid, Dracula and all the other cloud forest plants in the cold house and many Bulbophyllums in the warm house. 3 years ago, all of them were in SM. Usually every January I replace all the moss with fresh stuff as it gets grundgy and prevents maximum plant performance if allowed to get old and slimy. That may take me all month and use up 2 or 3 bales of moss. Its tedious busy work to tease the old moss out of a large rootball and the new moss is not cheap at $65 to $70 a bale.

I have been looking for a way to escape that drudgery and may have found it. Read the thread entitled 'With a strong, robust plant, you don't have to follow the rules' if this subject interests you at:

What was not brought out clearly enough in that thread is that this mix may be a viable alternative to SM. I have since discussed it with some orchid notables and they agree.

The plants that love sphagnum moss like to stay wet but you cannot choke their roots. SM serves the bill but needs to be replaced yearly. What are the alternatives? Regular pine bark is out as it absorbes too much moisture and would strangle the roots in the middle of a pot in an airless, wet, compacted ball. Orchiata bark, twice as expensive, is hard and does not absorb too much moisture. If planted in it, along with some lava rock for moisture and air, (2 parts bark, 1 part lava) one can water this mix daily and not strangle the roots.

I have been experimenting with this for close to 3 years and have numerous Pleuros, Dracula, Odontoglossum and Masdevallia growing in this mix. These are all large, strong plants, the little, young ones stay in moss. They get watered either daily or every 2 days hence stay wet enough. The hard Orchiata does not compact into the airless mass that regular bark or coconut does.

Instead of repotting every year with moss, which is twice as expensive as the Orchiata, I need to repot every 5 years, the life expectancy of this type of bark. Growing in SM is therefore 10 times as expensive and at least 5 times as labor intensive. At this time I have every reason to believe that this is going to work and am in the process of switching all of my cold plants into this mix, as long as they are big enough. After that is completed, I'm going to attack the Bulbophyllums and see if they'll allow themselves to be grown like that.

If this works out as I hope, it could have a profound affect on the growing technique of plants now grown in SM. An alternative will be available. I was talking to the people at SBOE and there is great interest in this. A word of caution: No need to avoid SM if you have a small number of plants in it, it is a proven winner. If however, you have a goodly number growing like this and have the time for frequent watering, then this might warrant consideration as it will save you a ton of work and money.


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shavedmonkey (Harvey in South Fl.)Z10b

I use sphagnum moss sparingly. I stuff it in the cracks and holes of cork bark for extra pockets of moisture and feed. In the past i was using a lot of a mixture of bark, charcoal and perlite. The latter would compress and require extra work. Now I use mostly lava rock.

This works for me partially because I'm heavy handed with the hose. Also there is plenty of humidity where I live. Also to have potting medium longevity I use Orchid plus fertilizer which has no urea. That saves on salt build up. Now I never repot because of a medium breakdown.

The above recipe along with cork mounts has been an improvement for me. However, my observations tell me that there are many successful formulas. But all formulas are not for all people. I'm certain that if I used my formulas in a different climate I could have complete failure. Or if I had less time for orchids my methods would dry them out.

If there are a large number of plants in the balance then experimentation early to be sure. Just like Nick did. Without doubt there are dozens of ways in use that are successful. But each method is not for every situation. That is why newbies should get advice from locals. They have the climate in common.

    Bookmark   July 16, 2014 at 3:25AM
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Skie_M(Zone 7 (Southwestern Oklahoma)

I've seen some plants that use pretty much pure water with nutrients added growing VERY WELL in something that you might have just overlooked ... artificial snow.

If you want to try it out with a smaller plant, the process is actually painfully easy ... clean off the roots of the plants and insert in new pot. To give the plant something to cling to, you can use a handful of rocks for the roots to wrap around. Pour in the artificial snow mix ... add water.

Excess water is soaked up by the artificial snow and released over time. You can use water created from composting "tea" for additional nutrients, or use a fertilizer of your choice.

    Bookmark   July 16, 2014 at 3:51AM
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I like growing in sphagnum. I have mostly phals. One is in what i believe to be orchiata. The pieces are very uniform and rounded. I am not used to it yet, but i like it better than the miracle gro bark.

Most of my phals are in sphagnum. I just switched one to 50/50 bark and (new) sphagnum, since the sphagnum it was in was old and was starting to rot the roots. The other mini is in fresh sphagnum and growing like a weed. It has put out, by my estimations, about 6 inches of roots (as well as 4 or 5 inches of leaf) in the time I have had it. No more than two months.

Sphagnum is great while it is fresh, and with healthy roots. Not so good with damaged roots. Or when the sphagnum breaks down. Still, being an orchid noob, I prefer it.

    Bookmark   July 16, 2014 at 3:56AM
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arthurm(Sydney, NSW AUST)

For those interested here is a long thread about Urea.

Here is a link that might be useful: Past thread on Urea

    Bookmark   July 16, 2014 at 5:52AM
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So, in regards to fertilizer, am I likely to harm my plants by using distilled water, rather than tap water? I alternate between distilled water and spring water with most of my plants, save those who arent sensitive to the chemicals in the tap.

    Bookmark   July 16, 2014 at 12:37PM
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arthurm(Sydney, NSW AUST)

I do not know the answer to this question save the fact that most of the 50 or so active members in the local orchid society happily water from the tap.
What about cloud forest orchids, maybe some of those are super sensitive to water PH and so on?
I'm watering from the tap because it hasn't rained much in the last few months and 3000 Litre rain water tank has run dry. Sob!
There is such a thing as too many sunny days.
If you are worried about water quality, have a look at the web-site of your water utility and that will tell you what is in the water.

    Bookmark   July 16, 2014 at 1:11PM
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highjack(z6 KY)

Nick I've been growing my Bulbos in sphag lined net pots with Orchiata and Growstone as the media for the last few years. I also sit the net pots in about an inch of water. The roots grow in and out of the baskets and into the water. The Growstone is like lava rock but made of recycled glass and is quite light to lift.

I've been growing my Masdies in the same mix for the last two years in Cool Pots made of clay and have a solid bottom with no drain holes but do have holes in the sides about an inch above the bottom. They are loving it. A constant supply of wet bark in the bottom but air through the side holes with the evaporation through the clay. I have a friend who uses regular clay orchid pots with the holes but sits the pot in a saucer of water = evaporation, holes and water in the bottom - happy Masdies.

I love growing both species in this manner because it reduces my time to water plus I use less of my rain water supply.

Can't help you with the others you mentioned because I only have a couple and they grow in net pots covered in moss.


    Bookmark   July 16, 2014 at 1:50PM
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I listen to the good growers I know who use RO water for species growing. To keep it simple, I have 2 sections of my warm house, one with mostly Bulbos and other species, the other with Catts, Oncidiums, Stanhopeas etc. The Bulbo section (not that Bulbos are sensitive) and the entire cool house gets watered with RO water, everything else with tap water. I use urea free Grow More, 20-10-20 with the tap water and MSU fertilizer with the RO. I use a wetting agent with both. I have been doing this for so long, I don't give it much thought anymore, it seems to work.


    Bookmark   July 16, 2014 at 1:50PM
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Love your post, Brooke. Confirms what I'm saying but using a different approach. I knew I was not the inventor of sliced bread but no one in my circle uses anything other than SM for these plants. You are basically using a semi hydroponic approach without moss which makes sense as these 2 do not get along. SBOE grows a few Pleuros in bark but they are not really into these plants. Andy, the God of all Gods we all worship here, grows them all in moss.


    Bookmark   July 16, 2014 at 2:05PM
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shavedmonkey (Harvey in South Fl.)Z10b

I've been using the same fertilizer from Sun Bulb more than 20 years. The product is called orchid plus. On the package it indicates no urea. A few years ago the AOS endorsed it. Written on the package. For what that is worth.

It is difficult for me to get my arms around what is right or wrong. I do know that my plants seem healthy and strong. The question is if I change what I do will it improve the plants. That means change anything including feed.

So I decided to call Sun Bulb and they sent me an email from Robert Palmer, their master grower. This is his response about urea.

Dear Harvey: Tina asked me to contact you about the no urea in Orchid Plus. Using a fertilizer with Urea tends to drop the media ph very low after extended use. It will not harm your orchid if you are using a fertilizer that contains Urea, we are not making that claim at all. Many orchids are grown mounted or in the case of vandas in a basket with no mix or media whatsoever. In these cases all fertilizer runs off on the ground immediately . This does not allow for the urea to be converted to the ammonia(NH4+) or nitrate(NO3-) ions. Urea can be taken through the foliage but the plant responds better and faster using nitogen in the nitrate and ammonia forms. Roots do not take up nitrogen in the urea form. Low temps in the winter especially slow down the conversion process of nitrification by the soil microbes. I hope I have explained this properly to you. Using any fertilizer is better than using nothing even if the fertilizer contains urea.
Sincerely Robert Palmer

I believe that from now to the end of time this subject will continue to be debated.

    Bookmark   July 18, 2014 at 8:52AM
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I believe for plants growing in the conventional media like bark, It makes very little difference as the bacteria convert the urea. For bare-root plants that does not happen so there it makes sense not to use urea.

Since it is just as easy to get 20-10-20 than 20-20-20 why not avoid the head scratching, lip flapping and tongue beating and get the urea free fertilizer.


    Bookmark   July 18, 2014 at 9:24AM
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