The care and feeding of sphagnum moss

orchidnickJuly 20, 2014

2 nights ago we enjoyed a talk, actually a 1 hour culture session, from George Vasquez, the owner of Zuma Canyon Orchids, one of the premium growers of Phaelies. He had things to say about SM that I did not know and found amazing. He claims that the moss can stay healthy and fresh for 5 years but that over watering and over fertilizing causes the breakdown I'm used too and so many of my compatriots report.

A Phaelie packed into a 4" pot of SM gets a turkey baster full of water once a week. The moss should be almost dry, on the surface only, by the end of the week. This small amount keeps it moist but not wet. Fertilizing should be so weak that at no time green algae or moss grows on the surface of the pot. The moment you see green moss appear, half your fertilization rate. Use a low nitrogen formula, Nitrogen is only needed when growing in bark.

If you follow this advice, Phaelies should be happy and should need a larger pot on a yearly basis. Moving up happens in 1" increments. He does not remove the old moss, just adds a circular layer of new moss and then shoves everything in the next size pot. He claims the moss stays healthy for 5 years hence no need for removal.

I do the opposite of everything he stated. I water heavily and welcome the appearance of green moss as a sign of a healthy environment. Of course I'm not talking about growing Phaelies but Pleurothallids, Masdies and Dracula which love to be wet. Don't know if the above advice applies to these plants.

Since so many on this forum appear to be focused on Phaelies, I thought I'd pass the advice on. On a similar vein, we had some advice from Tom Miranda of the Smithsonian who said that SM will grow luxuriously if watered with pure water only. No fertilizer at all.


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arthurm(Sydney, NSW AUST)

Yes, but you can bet your booties that these guys are growing their babies in ideal Phal. House conditions.
Not so ideal in this room where the poor babies are potted in bark + perlite.

    Bookmark   July 20, 2014 at 3:03PM
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I'm opposite of you Nick. I forget to water.

It is very hot and humid in Florida during the summer. For me its been tricky growing them here. I don't know if your expert takes climate into account when talking about using Sphagnam. I also find that Phals begin to stress when the temps stay so high as they have been over the past month or so. I'm tempted to bring them in the house but...not that tempted!

I find Phals do best with Sphag but I've been adding some orchiata or perlite to the sphag. I've moved many into pots or baskets with better air circulation. I have also found that when Sphag dries on the surface it is hard to wet.

I've begun dunking the smaller pots in a bucket to better wet the media and making sure that the dry sphag doesn't block water from reaching underneath.

As much as I forget to water, I also forget to fertilize. All of my orchids are treated the same.


    Bookmark   July 20, 2014 at 9:50PM
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That's interesting about the algae. There is some in one of my minis. I had both my minis in sphag, but I switched one to 50/50 bark and sphag because its damaged roots were inviting rot (and the original sphag was old).

Anyway, the mini in sphag does have algae growing on one side of the pot. But I water with 7-7-7 diluted to 'every time you water'. I flush it once a month with distilled. I feel like that cant be too much fertilizer.

    Bookmark   July 21, 2014 at 11:38PM
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Darlene (GreenCurls)(6a)

I dont use a lot of sphagnum anymore. I am guilty of under watering and, as Jane stated, it is difficult to rewet sphagnum. Plus I water all my orchids with the fertilizer solution so I do get algae growth on sphag. I limit my use of sphagnum to basket culture. But I dont replace the in my baskets and they seem to be ok so far. Probably not the best thing to do. The few Phals I have are in pots with bark because I have not been able to get the culture correct with sphag. Maybe I will try again.

I have a Cattleya violacea seedling and a Laelia praestans in sphag in a clay pot only because that is how the vendors had them.

    Bookmark   July 22, 2014 at 5:36AM
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highjack(z6 KY)

Fertilizer does not necessarily create the algae - light will make any wet sphag turn green. I always pre-soak my sphag over night in plastic shoe box size containers. I will get algae anyplace light hits it from just the dampness on the sphag.

If you use good quality sphag I don't have any issues after years of it being in a pot. Until the Lycaste needs to be divided, it just gets up potted with me plopping it in a bigger pot and stuffing new media around the edges. Lycaste have very fine roots that are brittle and I don't want to disturb them because they wind around and around the inside of the pot. In their growing season they get fertilized every watering.


    Bookmark   July 22, 2014 at 9:33AM
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i used to grow phals in osmunda fiber - those were carefree times... i hardly did anything, occasional ferts, but very casual. they just grew and grew and offset and bloomed. the bark on the other hand is a total pain-ITB...for fertilizing/watering...
currently they are in med bark with LF SM snippets, some scoria and orchid slitted see-thru pot lined with coir husk matting for more aeration. roots are getting much better since i introduced coir matting (like for wire baskets, but looser, not smooth packed).
this is strictly indoors.
but i am very intrigued about growing in sphag and barely wetting. i just ordered NZ LF sphag too.
what i don't understand about planting in sphag - why do they pack it so tight in newly bought plants?
i always loosen it up and remove close to half of it - since the plant is in bloom i don't want to repot immediately, but i am just too scared to water it while i have like a quart of packed sphag in a tiny just never dries up when packed tight!
so, if i were to repot a phal in pure LF SM how should i pack it?
and what about using half very large bark and half LF NZ sphag by volume? how would you measure the sphag? packed, loose, half-packed?

    Bookmark   July 22, 2014 at 12:33PM
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I can only say that George Vasquez from Zuma Canyon, probably the beast Phaelie grower around here, packs his moss super tight. I have never asked him why but I'm sure he has a good reason as the stuff is not cheap.


    Bookmark   July 22, 2014 at 1:06PM
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When I get a new orchid I pull out most of that tight-packed moss, otherwise the roots rot.. after blooming I do a partial repotting, put fresh bark and add some Styrofoam bits in the bottom for better drainage...but my orchids are outside in the trees... I think the growers pack that moss so tight because if they didn't the plant dries out in the store, what they don't care abt. is the over-watering that occurs so often... too bad...sally

    Bookmark   July 22, 2014 at 2:17PM
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I dont think you need to measure if you are mixing bark and sphagnum. Just eye it up. I used small bark pieces with mine. Maybe 1/2 inch or less.

    Bookmark   July 22, 2014 at 6:48PM
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i am specifically interested in finding out the reasoning for packing tightly. if it's to prevent drying out for longer-then-normal-watering-period (shipping/shop time), then my reasoning for half bark in the mix would be:
large bark dries faster and is harder to rewet (dunking is necessary). then if i pack tight with large bark - it might provide better drainage/aeration, while still providing considerable 'just-moist-enough' period.
bark needs constant fertilizing, what about when it's packed tightly with sphag? it won't dry out completely at all? will it wick moisture from sphag? how much fertilization will be necessary compared with constant feed for bark and very-rarely for sphag? half-way?
i went and measured the capacity of my standard old baster - it's 1/4 cup. apparently some are smaller/larger.
i am very tempted to try the technique exactly as suggested. but i am scared ;).
i just hate growing in bark/bark mixes - it does not work for me. never did.

    Bookmark   July 23, 2014 at 11:35AM
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I dont know about all that. What I have noticed since adding 50 percent bark to my sphagnum is that it keeps the sphagnum from being sopping wet, and allows it to dry faster. I also think the sphagnum wicks water from the bark, so it is easier to tell when to water as opposed to with just bark.

The only thing I dont like about it is trying to mix it. The moss likes to clump together and the bark likes to fall to the bottom. They separate like oil and water. It's annoying.

Once it is in the pot it works great.

    Bookmark   July 23, 2014 at 8:12PM
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Perrushka, check on the 'Phaelanopsis experiment thread. I'm planning to grow one in tight moss and one in loose moss side by side. Might also add one with bark and moss mixed 50/50. Give me some ideas what else to try. These things will need my attention for a while, I'll never do it again


    Bookmark   July 23, 2014 at 8:12PM
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nick, i already looked thru the phal experiment thread. i think it's very interesting what the outcome will be.
i have some questions and thoughts - i'll go post there.
what you said is along the lines of questions that i was asking. so, may be there is smth in 1:1 idea...
notice that nick said NOT to water to sopping wet, but just barely enough. of course it'll depend on how many roots you have in the pot and how actively the plant is growing and also growing conditions: temps/humidity, evaporation levels, etc.
i think that tighly packed SM will prevent water from running thru provided it's not dried up. but if it's not tightly packed, the water will just pour out.
how much to pack though? that is my question.
knowing some sort of 'volume measure' ahead of time can help to get more consistent.
the way i usually plant - i don't mix sphag with bark or other stuff ahead of time. i layer it in as i fill the pot by bits and pieces. it's easy enough to do by hand. you need to distribute it among the roots carefully anyway (that is i am assuming you have some roots ;)). so there is no oil/water problem. somewhat compressed SM will hold the other ingredients in place without shifting. whether it's bark or cork or scoria.
i have some 'deep thoughts' on scoria.. ;).which is like my total favorite!...i'll go sleep on it ;).

    Bookmark   July 23, 2014 at 11:28PM
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