# Algae in S/H pots... or not?



## e-spice (Jun 29, 2010)

Hi,

I grow most of my plants S/H style in clear plastic pots. A few months after the plant is potted or repotted, there is a nice film of algae covering the inside of the pot. It doesn't appear to hurt the plant too much and most grow just fine with it in the pot.

I sometimes wonder though, what would the plant would grow like if the algae wasn't in the pot. I have noticed my plants seem to grow roots best after they are potted when there is no algae present. Do you think my roots grow better if I put a sleeve on the pot to block the light which would reduce or eliminate the algae?

Thanks for any input,
e-spice


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## Shiva (Jun 29, 2010)

Algea is one of the reasons I gave up S/H. To me, being able to see the roots develop was a big advantage but when the algea gets too thick, you can't see the roots anymore. I began to grow semi-hydro about seven years ago and I got back to a bark mix gradually. The last plant I was growing in S/H got repotted in a bark mix just last week. I should say the last one of the seven years batch, since I put a Phrag kovachii in diatomite chips a few months ago. Like most plants I have grown in S/H, it's doing well but so is the algea.


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## Lanmark (Jun 29, 2010)

I grow most of my plants hydroponically rather than semi hydroponically. I use clear pots, and I find a dark sleeve works best for me. Without it, the algae grows, and I hate how it smells, not to mention I want to be able to see the roots.


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## Ray (Jun 29, 2010)

One might argue that algae prevents chlorophyll in the roots of plants from functioning, but putting the pot in an opaque sleeve would block the light as much, if not more.

Starting with a clean pot, a periodic (every 4- to 6 weeks) treatment with a dilute Physan or bleach solution will keep the algae at bay.

Frankly, i see no difference between the growth and blooming of plants in clean versus algaefied pots. In fact, the plants I leave more-or-less alone, grow and mature in some really yucky looking pots, and seem to reward me with blooms quite nicely.


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## Bob in Albany N.Y. (Jun 29, 2010)

Ray, I'm sorry but you're not going to like what I have to say. This is my experince only and everyone needs to come to there own judgment. I grew in S/H for 5 or more years. Everything did great for the first couple of years and then saw a decline in many of the plants and deaths of many. It was at the point that I had algea covering the inside of the pots and the worst ones where the ones that had moss or whatever growing over the top of the pots. I personally don't like the idea of using physan (even at a very reduced strength) on a regular bases, never mind every four to six weeks. The idea of S/H appealed to me due to the thought of doing less work. Less repotting meant less work and over the long run a leaner greenhouse budget. For me it just didn't work. I'm now back to a bark mix and some of the S/H plants are still trying to recover. It seems all the new acquisitons that have never been in S/H are just going gang busters. Remember this is just me experiece and everyone needs to make up their own mind in regard to this matter.


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## Shiva (Jun 29, 2010)

I agree with Bob. I thought using S/H would simplify things and make for less repotting. But it complicated things instead. Other than the algea, some plants never adapted to this culture and I could never tell the ones that would or would not. Then, there was the annoying accidents. A pot tipping over with the clay pellets rolling everywhere. And the extra weight. Different kind of fertilizer. In the end, you have plants in S/H, plants in bark mixes, plants in sphagnum mixes, plants in tree fern... each requiring different watering and fertilizers. Now I simply use a fine bark mix or Aussie Gold for fine roots like those of many paphios and masdevallias, with the mix getting coarser the bigger the plant is. The only exception as I said is the phrag kovachii which requires a higher pH and is growing in diatomite chips. I could put a sleeve on that pot to prevent the algea buiding up again. I must have an old sock somewhere...


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## NYEric (Jun 29, 2010)

It's funny but personally, I'm thinking of putting more phrags in aliflor in my circulating water trays. maybe it's the circulating water that does the trick?!  Yes I have added holes at the bottom of the pots so water should be going in. I think S/H gets too dry as a technique. I also note that my house is so dry that I don't get a lot of algae!


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## Lanmark (Jun 29, 2010)

I've found that even dilute applications of Physan cause the root tips on my Neos to stop growing. They actually lose their fresh live tip and get that thin white cork film over them and go dormant for about six weeks. Then they spring back into action. No browning or dieback occurs, but it definitely stops them in their tracks temporarily. Physan is a last resort for me when it comes to my Neos.

In clear pots, the only roots getting any light are those near the wall of the pot anyway. The other roots on the interior aren't getting any light at all. I don't see a problem with that. When my Neos put out new roots, they get light until they dive down into the pot. It's always been that way whether they are grown in a pot on a mound of moss or in pot full of rocks.

Growing a plant mounted or in a basket which has no solid walls will minimize the growth of algae. Some plants, of course, must be mounted, especially those which rely on significant levels of photosynthesis occuring in their roots. Even my mounted plants occasionally need to be cleaned with physan, but I avoid doing it as much as possible. Mounted Neos grow especially well for me, but I use hard wood or rocks as mounts, very little moss, high light and plenty of air circulation thus providing them with daily or twice-daily wet/dry cycles.


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## Ray (Jun 29, 2010)

Bob, et al - Your observation is a valid one, but I doubt that it had anything to do with algae, unless it had completely clogged the top and the holes.

Instead, I think it clearly points out that EVERY type of medium accumulates salts over time, and that they need to be changed out periodically.

With traditional organic media, they decompose fast enough that we naturally replace them. The tendency with inorganic media that don't decompose - diatomite, lava, pumice, LECA, etc. - is to leave the plants in them much longer without doing so, and depending upon the specific medium type or brand, the watering frequency, feeding regimen, and even to some extent the plant (faster grower=more waste products), it is possible to reach an "issue point" sooner or later.

If it absorbs, it accumulates. How well it releases affect the retention rate.


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## Lanmark (Jun 29, 2010)

I'm hoping for nanobots to be invented soon which will clean up the algae in our pots for us! 

Hey, a boy can hope anyway, can't he?! :rollhappy:


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## likespaphs (Jun 29, 2010)

NYEric said:


> ...my circulating water trays. maybe it's the circulating water that does the trick?!  ...




i believe you are correct. i don't know if it entirely eliminates algae or just significantly slows it.


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## Mrs. Paph (Jun 29, 2010)

I like the nano-bot though lol. In the mean time...I haven't used it yet on a plant in the pot (b/c the algae hasn't bothered me enough), but when I clean LECA to sterilize and reuse I do a pre-soak in a bucket with pond algae killer. It seems to help wash the algae off the surface of any of the pellets that were in the very bottom of the pot or the surface that was touching the inside wall, and since it's formulated for use in ponds with plants and fish, that Could potentially mean it would be safe to use on the orchids while they're growing in the pots...you do need to agitate the water to help it work off the algae though, so I suppose if I try it I'll pour the solution through the pot, let it soak in the reservoir for a bit, then rinse with plain H20, let it sit again, and repeat etc. until I felt I'd washed out some algae & the rest of the algae killer... Unless you're totally clogged up with algae though, I haven't seen it negatively affecting my plants (I also have not left a plant in the same pot and media for more than 2yrs), but that's one of the many things about S/H that strikes up debate. I recently gave a short talk on how/why I do S/H at my local society meeting - For Me, it simplifies my smaller side-collection of non-Paph orchids so I have some easy-blooming Phals & Catt types to enjoy while spending more time on Paph growing! Most seemed to at least not be bored, some wanted to try it, while one actually interrupted to say that it started plant roots great and then made the plants get smaller and smaller...there's still so many variables to control and experiment with before you blame a potting mix for helping or hurting your plants - like any other potting method, the media and pot type are only part of the equation for growing! If the algae bothers, I say some experiments into slip covers and pond cleaner could be in order if you're otherwise having fun with the S/H experiment and have plants to test on!


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## goldenrose (Jun 29, 2010)

NYEric said:


> ....... maybe it's the circulating water that does the trick?! ......





likespaphs said:


> i believe you are correct. i don't know if it entirely eliminates algae or just significantly slows it.



Tell that to the algae that grows on our rock waterfall in the pond every year!


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## etex (Jun 29, 2010)

Um... Do you need a different fertilizer with S/H? I have been using dilute MSU for RO on my phrags in S/H every other watering. Do I need to change fertilizers?


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## Mrs. Paph (Jun 29, 2010)

I don't think you need to change fertilizers, no. I think what was meant is that you may want to use a more dilute mix of your fertilizer, since when you water in bark/CHC type mix very little of it stays after the water runs through, but in S/H it stays down in the reservoir, meaning more probably gets used by the plant since it's available to it longer, so not as high a concentration is needed. For me it just means I water a couple plants in traditional mix, then set the gallon jug aside, top it off with more plain water, and go outside and water the S/H plants with it! You could get more technical with it, but that's what works for me.


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## etex (Jun 29, 2010)

Good! Thanks!!


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## bullsie (Jun 29, 2010)

When algae builds up too heavy in my s/h pots, I change them. I can't say that my bark mix in clear pots are crystal clear as they unquestionably show algae on the sides. Either way, I have algae. Just that my s/h plants get repotted every other year to nice clean hydropellets so the algae can start all over again.


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## Lanmark (Jun 29, 2010)

bullsie said:


> When algae builds up too heavy in my s/h pots, I change them. I can't say that my bark mix in clear pots are crystal clear as they unquestionably show algae on the sides. Either way, I have algae. Just that my s/h plants get repotted every other year to nice clean hydropellets so the algae can start all over again.



Yeah, like you said, and others before you, it's a good idea to repot once in a while and clean things up, no matter what method you use to grow your plants. It's called good housekeeping.


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## orcoholic (Jun 29, 2010)

I'm just curious. Has anyone ever received a growing award (CCM, CCE) or seen one awarded to an orchid growing in S/H.?


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## Candace (Jun 29, 2010)

orcoholic said:


> I'm just curious. Has anyone ever received a growing award (CCM, CCE) or seen one awarded to an orchid growing in S/H.?



All my AOS awards have been on plants growing in S/H. Though I've moved my paphs out of it. Like Bob, they did great for 4 or 5 years and then crashed. But my catts and other orchids are still in s/h and they're loving it.


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## Eric Muehlbauer (Jun 29, 2010)

For me the thing with S/H was that it was so hit or miss....most plants hated it, the few that loved it thrived...it didn't seem to matter what type of plant. So now I have 2 S/H plants...an enormous Phrag and a cattleya. I'll continue to keep them that way, and maybe experiment occasionally, but for the rest of my plants, its traditional...bark for paphs and phrags, CHC or sphagnum for epiphytes.


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## SlipperFan (Jun 29, 2010)

I think we have two issues here: growing in S/H and growing in clear pots. Most of my collection are in clear pots, but only a few are growing in S/H.

I agree with those that said repotting (in any media) tends to give plants a growth spurt, and that repotting should be done more frequently that you might think if you are growing semi-hydroponically.


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## e-spice (Jun 30, 2010)

orcoholic said:


> I'm just curious. Has anyone ever received a growing award (CCM, CCE) or seen one awarded to an orchid growing in S/H.?



Here's a couple of CCE's that my friend Rosalie won growing them S/H last year. These were a couple of the most impressive paphs I've ever seen in person.


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## Shiva (Jun 30, 2010)

They certainly are beautiful but it begs the question: would they have been as beautiful growing in a traditional mix?


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## NYEric (Jun 30, 2010)

!! Wow!


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## Candace (Jun 30, 2010)

Shiva said:


> They certainly are beautiful but it begs the question: would they have been as beautiful growing in a traditional mix?



The conditions, nutrition, light and air movement- i.e. culture are 99% of the outcome IMHO. A good grower will be able to grow in any mix. Used tires, traditional mix or nothing at all if the culture is tweaked. Obviously this person is a good grower. So yeah, I think her plants would be as amazing in ANY mix.


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## Ray (Jul 1, 2010)

Eric Muehlbauer said:


> For me the thing with S/H was that it was so hit or miss....most plants hated it, the few that loved it thrived...it didn't seem to matter what type of plant. So now I have 2 S/H plants...an enormous Phrag and a cattleya. I'll continue to keep them that way, and maybe experiment occasionally, but for the rest of my plants, its traditional...bark for paphs and phrags, CHC or sphagnum for epiphytes.



I don't believe it's a "hit or miss" thing at all, but more of a matter of getting the plants to become established in the new root zone environment and making sure that the changes the method provides (primarily lots of evaporative cooling in the pot) doesn't take you outside of the "happy zone" for the plant.

I agree that if you take a collection of plants and move them at once into semi-hydroponics, some will make it and others won't, definitely giving the appearance of "hit or miss". If, on the other hand, you pot up plants just as they are forming new roots, it is likely you'll have close to 100% success.

I recently got in a batch of species seedlings. A few were growing new roots, many were not, and some didn't have any roots at all. After potting them up, I moved them onto a seedling heat mat, and in less than 2 weeks, all have new roots growing and are getting nicely established.


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## Shiva (Jul 1, 2010)

Candace said:


> The conditions, nutrition, light and air movement- i.e. culture are 99% of the outcome IMHO. A good grower will be able to grow in any mix. Used tires, traditional mix or nothing at all if the culture is tweaked. Obviously this person is a good grower. So yeah, I think her plants would be as amazing in ANY mix.



That's what I thought Candace. I also think that you have to get a real good plant to get that kind of result. For instance, I could lift heavy weights forever and never look good. Genes are also important.


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## Jim Toomey (Jul 1, 2010)

Shiva... I have to agree & disagree.

If you have the right nutrition and have proper training for your body type
you can look excellent!

It does have to do with genetics, but you can really modify your body to look its best.

Much like our plants, correct conditions will maximize their potential.
Crummy conditions will rot the best of them...

Agree?


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## Eric Muehlbauer (Jul 1, 2010)

Actually Ray, I had other plants that initially took to S/H..you are absolutely right...if new roots are growing, success is more likely..no new roots, forget it. However, most plants that took to S/H didn't last for long...some lasted a few weeks before declining, others a year or more...but still declined (despite repotting). These 2 are the survivors...and they are still thriving.


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## Ray (Jul 2, 2010)

Eric, don't forget the interaction of your growing conditions! "Semi-hydroponics" is not a complete definition of orchid culture. At most, it addresses water and air supply, and there's a lot more parameters than that.

For example, you said that your slippers do best in the CHC-based mix, while for me, S/H is far superior. That certainly says it has nothing to do with the plants themselves, suggesting that our overall growing conditions favor different parameters for success.

Another thing to consider besides the growth of new roots is how different the previous root zone conditions were from those in the S/H pot. A plant coming from sphagnum often takes to S/H like falling off of a log, while one that had been in a coarse bark mix will take far more time and babying to make it happy.

Without a doubt, one of the most significant factors that affects the conversion process - and long-term success - is that of temperature. As I mentioned earlier, courtesy of a recommendation from a grower in Michigan, I started using seedling heat mats under the pots whenever I transplant, and it has made a huge difference in the success rate. But we had better not forget that the evaporative cooling coming from the open medium can affect the plants after they are established, as well. I cannot tell you how many phals I killed before I realized that. Growing them at the minimum temperature I could get away with over winter became a death sentence for those in s/h culture, while those in bark or CHC fared better. Boosting the temperature reversed that.


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## Justin (Jul 2, 2010)

i haven't tried SH myself, but i saw Ray's presentation at our O.S. and it was impressive. My collection is under 200 plants so bark mix is manageable.

Semi-hydro makes perfect sense, but i'm surprised to hear that some are using recirculating water systems or full hydroponics for orchids...i would be extremely concerned about virus.


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## Eric Muehlbauer (Jul 2, 2010)

Actually Ray, I've completely given up on CHC for paphs. Except for philipinense and its hybrids (some of which are still in it) which love CHC, I found it to be very damaging in the long run, especially for barbata types. I've completely switched back to bark..and I'm very happy with orchiata bark. On the other hand, Cattleya's, Vanda's, Oncidiae, and Dendrobiums..in fact most epiphytes with pseudobulbs love CHC. (Pleuro's and phals go into sphagnum or bark).


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## Ray (Jul 3, 2010)

Sorry Eric. I must have misread your earlier post.

Much as I tend to avoid bark, I have been using Orchiata on some seedlings of C. harrisoniana, C. schilleriana, and Epi, stamfordianum as an experiment, and they seem to take to it quite nicely.


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