Growing in damp sphagnum

[ALToronto]

I had terrible results in sphagnum until I realized that the key to using it is to not soak it until water runs through. Now I'm getting very good root growth in plants that are growing in barely damp loosely packed sphagnum. I use a fine nozzle on a pump-up sprayer to just moisten the top 20 mm of the pot (3/4"), without getting any water/fert on the plants themselves. I do this every 4-5 days for plants that are growing in plastic pots; more frequently for plants in net pots. I'm growing at home, where humidity right now is 70-80% (I don't like or use air conditioning).

So far, so good, but I just started using this method with a few plants. And I realized after I potted the plants that I probably should have soaked the sphagnum in CaNO3/MgSO4. I'm using RO with K-lite at every watering, about 20 ppm. I'm using mostly NZ moss, although I ran out and had to put some plants in Chilean sphagnum (wow, what a difference in quality!).

Since I didn't do the cal/mag soak, should I do it now, together with or instead of a regular fert watering? I'm afraid to do a flow-through pH measurement as it will saturate the sphagnum and likely lead to rot problems with the plants. However, without flow-through, am I concentrating the fert to very high levels, or are plant roots taking up most of it? How can I tell? Should I reduce the concentration even further, to 5-10 ppm?

Appreciate any comments/advice. Also curious as to how I should adjust my watering method/schedule in the winter, when humidity will drop to 40-50%?

 

[orcoholic]

I don't think that watering at 20ppm will cause any problems at all - ever.

I have to admit, I've never heard of watering only the top half of an orchid. If anything, I'd be afraid fertilizer salts would accumulate in the pot. I use NZSM a lot on Phals and never soak it in CaNO3/MgSO4 first. Never heard of it. I do wet it pretty thoroughly with my regular irrigation water - about 400 total ppm, Ph 6.5. When I water I do so until a lot of water comes out of the pot. Why would roots continue to grow if there were nothing to go after?

I do pack the moss pretty tightly so the plant will stand straight.

As far as adjusting your watering method in the winter, it's best to water most orchids when they are almost dry - regardless of the season. Some need special care e.g. witholding water completely during the winter, but as a general rule water when they are just about dry.

If your humidity is too low, add some with a cold air vaporizer. You may need to water a little more frequently in loose packed moss in lower humidity, but remember too frequent watering when it's cold can be a problem.

 

[Rick]

I've never done an Ca/Mg soak on sphagnum, and I stopped using straight moss in pots a ways back. I found it's great for starting roots, but after a few months of heavy feeding things get bad again.

Long term, I only use it straight in few baskets with a Bulbos. For the paphs and phrags in baskets its used in conjunction with lots of big chunky limestone gravel and sand.


Because of the cation exchange as well as water retentive properties, moss will not only accumulate K, but all the trace metals in your fert. I don't know which is worse in the long run. But usually I end up with lots of live moss or ferns kicking in, which probably helps suck up all the excess metals too.

I know some Phalae growers that use straight moss too. They water light, feed monthly, and try to sell all their plants within a year to avoid having to repot. But stuff grows like gangbusters during the time they have them.

 

[keithrs]

Sphag seems to be fest or famine for most folks. I do ok in it but I prefer to use bark or mount plants as I'm a heavy waterer. I would suggest using aragonite sand instead of do Ca/Mg soaks as it will wash out fairly fast in sphag. I would also suggest using baskets, clay pots and such that allow air movement. Than you'll be able to get the sphag wet and not worry about roots. Only experience will prove whats best for winter watering. Obviously you'll want to water as the sphag is almost dry, but how often is the ? that experience will answer.

 

[gonewild]

Something to consider is that Sphagnum moss is a swamp plant.
Orchids do not grow naturally in sphagnum moss.

Orchids do grow naturally in moss but not swamp moss and not in tightly packed wet moss.

Most comments about growing in sphagnum moss imply plants grow well to start and then decline as the moss decays. This suggests that as the moss decays it is releasing an imbalance of nutrients (chemicals).

From looking at orchids growing in moss naturally it seems that the moss in a pot should be very loose and not tightly packed.

I used to think Sphagnum moss was a good growing media for pots but not now. Wet dead sphagnum moss is too unstable and unpredictable.

 

[NYEric]

I can use moss because our apartment is pretty warm. I don't soak it in any chemicals.

 

[phrag guy]

I grow 95% of my phrags in moss and have no problems.

 

[ALToronto]

Thanks for the replies. I was afraid I would get a full spectrum of answers. But since the sphagnum is fresh, I guess I have up to a year to figure out which medium to use next - even if it's fresh sphagnum again.

As for sparse watering, the water does migrate through the entire pot and dampens the sphagnum evenly. The point is that the moss is not sopping wet, but slightly damp. The roots seem to really like it.

My phrags, however, are in LECA - one in semi hydro, one in draining (kept very wet). They seem to be doing well.

 

[Stone]

Something to consider is that Sphagnum moss is a swamp plant.
Orchids do not grow naturally in sphagnum moss.

Orchids do grow naturally in moss but not swamp moss and not in tightly packed wet moss.

Most comments about growing in sphagnum moss imply plants grow well to start and then decline as the moss decays. This suggests that as the moss decays it is releasing an imbalance of nutrients (chemicals).

From looking at orchids growing in moss naturally it seems that the moss in a pot should be very loose and not tightly packed.

I used to think Sphagnum moss was a good growing media for pots but not now. Wet dead sphagnum moss is too unstable and unpredictable.

Agree totally. For me, sphag moss (by itself) is the single most badest medium! I think it works if you only grow one type of orchid and control every drop of water and fert. There are so many better alternatives but for propagating it has no equal.
The Japanese use it well but then they are Japanese.

 

[paphioboy]

I have gotten good results re-establishing rootless orchids (paphs and non-paphs alike) and also extended culture using just 100% sphagnum moss, loosely packed, DRENCHED at watering and then let to dry out over 2-3 weeks before watering again. The tight packing and moistening method is the one used by commercial phal growers.

 

[phraggy]

I use only sphagnum moss either Chilean or NZ it makes no difference to the plants although NZ looks more aesthetic. I've also stopped using the clear orchid pots in favour of the pots used for aquatic plants. Cattleyas love this especially when you let them get bone dry for a few days before drenching again.

Ed

 

[gonewild]

The Japanese use it well but then they are Japanese.

They have "discipline".

 

[Linus_Cello]

I use only sphagnum moss either Chilean or NZ it makes no difference to the plants although NZ looks more aesthetic. I've also stopped using the clear orchid pots in favour of the pots used for aquatic plants.

Ed

I'm only familiar with the relatively small aquatic plant pots (black with lots of slit openings, filled with rockwool and plant like crypt or amazon sword). Where does one get larger aquatic plant pots?

 

[The Orchid Boy]

I grow almost everything in sphagnum except for most of my paphs. I have a terrible time with bark unless it is in clear pots. Most everything is in straight sphag, sometimes with a little charcoal added. Everything from dendrobiums, cattleyas, oncidiums, phalaenopsis, masdevallias, a catasetum..... All are doing well most are in plastic pots, some in clay. All have drainage material in the bottom of the pot except for the phals.

I water them by totally soaking the sphag and letting water run through. I wait until the sphag is dried to a crisp all the way through, except with the masdevalllias, they get more water when the sphag is just moist. How long I wait after the sphag is dry until I water again depends on the orchid. All grow and bloom vigorously and the sphagnum is pretty packed, but not ridiculously packed like the big box phals are. I have humidity that stays around 75%. I'd like to try the "ultimate orchid basket", that plastic basket that has very large holes. I might try it with armeniacum and micranthum.

 

[The Orchid Boy]

I'm only familiar with the relatively small aquatic plant pots (black with lots of slit openings, filled with rockwool and plant like crypt or amazon sword). Where does one get larger aquatic plant pots?

You can find larger pots at nurseries that sell plants for outside ponds. Waterlilies and such come in them.

 

[terryros]

I am another 100% NZ sphagnum grower for my Paph, Phrag, Phal, Milt, and Catt plants. I am an indoor grower under LED lights. I think it was Ray some other place and time who made the point that it isn't wetness that is the downfall in sphagnum, since we know that orchids do well in S/H and even in pure water culture. It must be chemical imbalances that lead to trouble over time as the sphagnum is actively messing with electrolytes.

I feed at 40 ppm N with K-Lite with KelpMax at only 1:800. Like Rick, I need to add tap water to my fertilizer mix to obtain enough total alkalinity. I monitor the effluent of pots periodically for EC and pH. I also repot my plants at least once a year and often twice. All of these things are difficult to do with a large collection, but I can do it with about 100 plants. I also water each plant only when the top has gotten to the right degree of dryness for the type. I rarely see root rot.

There may be no perfect medium for growing, only one that works with all of the other conditions of the growing area.


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[naoki]

This is an interesting thread. I started to experiment with 100% sphag for a few plants (C. walkeriana and Sophronitis, not Paph, though) after I got amazing growth in rupicolous Laelia with 100% sphag.

Terry, when you water, do you give lots of water to saturate moss? I'm now switched to giving small amount of water to moisten (so I can water every 3-4 days). Then I reduced fertilization to avoid salt accumulation. Most of the time, they get 100% RO (with 100ppm TDS), and 50ppm N once every 3-4weeks. Do you add Lime-like things to counter the acidity?

It is rather amazing how some of Malaysia orchid nursery water orchids (well this info was about Phals). They use plastic pots + 100% sphag, and even with >5" pot, they give plenty of water every single day. The humidity is close to 100% all the time, and they don't have problems. This is kind of things which we were not supposed to do. Maybe there is enough air space to prevent suffocation of roots. I think Taiwan nursery does opposite thing (misting tightly packed sphags).

 

[goldenrose]

........ Where does one get larger aquatic plant pots?

Try a hydroponics store!

 

[ALToronto]

This is an interesting thread. I started to experiment with 100% sphag for a few plants (C. walkeriana and Sophronitis, not Paph, though) after I got amazing growth in rupicolous Laelia with 100% sphag.

Terry, when you water, do you give lots of water to saturate moss? I'm now switched to giving small amount of water to moisten (so I can water every 3-4 days). Then I reduced fertilization to avoid salt accumulation. Most of the time, they get 100% RO (with 100ppm TDS), and 50ppm N once every 3-4weeks. Do you add Lime-like things to counter the acidity?

It is rather amazing how some of Malaysia orchid nursery water orchids (well this info was about Phals). They use plastic pots + 100% sphag, and even with >5" pot, they give plenty of water every single day. The humidity is close to 100% all the time, and they don't have problems. This is kind of things which we were not supposed to do. Maybe there is enough air space to prevent suffocation of roots. I think Taiwan nursery does opposite thing (misting tightly packed sphags).

Acidity is my main concern. I'm tempted to add a few drops of an alkali silicate to my water. I have sodium, potassium and lithium varieties. I'm leaning towards lithium, unless someone here gives me a good reason not to use it.

As for the Malaysian orchid nursery, I wonder if they added a lot of sulfur to their water. Seems to stop fungus in its tracks. I just put two flasks' worth of phals into sphag-filled compots, and I've been using a sulfur fungicide quite liberally on them, with pretty good results (I've had a few flare-ups of the green fuzzies, but the fungicide takes care of them). These flasks are what prompted this thread - everyone's been telling me to just keep them in sphagnum.

 

[terryros]

I water thoroughly to be sure and wash out the whole pot. In my conditions, hardly any pot is watered more often than once a week and some go almost 10 days (larger pots). Most seem to think we want the moss to dry out fairly well, but I don't think you want the entire moss to be dry. I water Phals and Catts when the top surface is just getting crunchy. Paphs when the top is just barely moist, and Phrags and Miltoniopsis when the top is damp but not wet.

I think Ray has shown that media accumulates some toxic imbalances if it is not washed out and the pH changes over time. I think that is why I repot in less than a year, which would not be convenient for many.

Probably my big attraction to sphagnum is that I can water everything and be gone for 8 days and not have to worry about anything being too dry or arranging for someone to try and water. The literature on orchid growth in sphagnum shows a number of benefits, but you have to carefully control the downsides to get these benefits.


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