New to semi-hydro - my experience so far

[flowerpower]

Hi all. I thought I'd share my experience of growing my orchids in S/H, lessons learned so far and how my orchids are doing. For us newbies to S/H it can be a very worrying time when we first start this method - from what I read, I expected my plants to instantly succumb to root rot and die! Apologies in advance for the long post.

I have 4 onc's and 2 dendrobiums (nobile-type) in S/H for over a month now.

I converted these to S/H after the bark they were in broke down rapidly this summer (only 3 months). The room they are in gets very hot in summer and cool in winter (converted attic). The water requirement of these orchids was very high in the heat and the fine bark I chose was breaking down from the watering and heat after only 3 months. I noticed there was also insects had somehow appeared in the media - obvious sign the bark needs changing. I decided that the watering needs were high so semi-hydro might be a good solution to help save time and prevent media breakdown.

This is my set up so far:


The first oncidium is an intergeneric with 2 flower spikes from its pre-SH days. It is a Tahitian Dancer Pink Fairytale. The tag said Goodaleara but I heard its reclasssified as Aliceara. This orchid, from day 1, has been one of my best growers. It did get accordion pleating in the summer heat pre S/H but despite some issues with that, it has been such an easy orchid. It is perfect for a beginner like me - the bulbs stay plump and it produces roots rapidly. The new growth is not pleating in S/H (so far, so good!).



Looking at the roots, this orchid has not had any problems converting so far. The 3 new growths are also growing smoothly. However, I do have a residue - white powder - building up on the actual plant (possibly fertiliser but I have been using it quite diluted). This is a very fine-rooted oncidium but is doing very well. The only problem I faced in the conversion is that, while it has lots of roots, they always remain short on this orchid. It is almost just "sitting" on the LECA. However, it does not seem to mind.



The next oncidium is a Sweet-sugar style yellow one. I bought it with zero roots. I never expected it to survive. It has severely wrinkled back bulbs from its days with no roots. I recently popped it into semi-hydro. It has some roots now and the new growth is magnificent in comparison - I am hoping it might even spike! It seems to like S/H and is holding its own. It is quite a mature bulb but is still producing some new roots so I went ahead and put it in.



The next two oncidiums are both intergeneric NoIDs, they are large and have thicker roots. Neither did very well for me in bark. This one fell apart during repotting into two sections. I decided I wanted them to stay together so they are potted back-to-back in S/H. Luckily both parts have new growth. I have never been able to keep these pseudobulbs plump. They looked equally terrible in bark so I will keep going.



Another similar large-rooted oncidium similar to the Heaven Scent Onc's (it's a NoID), this one doing a bit better because it stayed intact. Some wrinkling but not much worse than when it first went S/H. New growth well on the way.



The last two are my den's...



My Den's are both nobile hybrids and I partially regret moving them to S/H for three reasons.

First, I foolishly put them in S/H when there are no small new growths, the growths are already maturing . The canes are a bit short but I do not mind as they did remarkably well to grow as much as they did. I bought them flowering in mid-summer a bit out of season for them. I am hoping for better canes next year where I will push them harder with fertiliser next year.

Secondly, I had problems with staking. I did not want my bamboo stakes to rot in the reservoir so I had to improvise slightly by taping the stakes to the side of the pot......



The third reason I regret putting them S/H is that of the winter rest for these orchids that want to go dry. I am really not sure how to manage that in S/H. I know the options are to dry them out or keep the reservoir filled but no fertiliser. I do not fertilise these at the moment but do water as the canes are not quite finished. I have adapted my S/H for the den's by keeping the reservoir full for a week and then draining it and letting them dry a little bit (I have no prospect of new roots for a long time so need to be a bit careful). I also read a post from Ray that Den's tend not to do as well as other orchids in S/H.

My reservoirs stay full for quite a long time so it has been overall an easy way of maintaining these orchids. When spring and summer comes and temps go back up I'm hoping to see some good growth.

It remains to be seen whether I will continue my Den's in S/H. I am going to leave them for now with the currently treatment and perhaps put the S/H full force in spring, when the new growths start. If anyone else has grown these in S/H I would love some tips. I will be starting their dry rest when they finish their canes in the next few weeks. I plan to leave the reservoir empty. I am already seeing some leaves yellowing here and there so I am pleased that they seem to know they are getting ready for winter.

Let me know what you think of my set up and apologies for the long post. If you have any criticisms or ideas to improve their care I would love to hear your thoughts.

[Ray]

An excellent post. Let me make a few comments that may help you a bit.

1) Any plant can be grown in semi-hydroponics, but whether "you" (any individual) can do so depends far more upon their growing conditions and watering habits than it does the plant itself.

2) When you move a plant into S/H, the existing roots will likely fail, because they have grown to be optimized for the conditions they WERE in, so won't be optimal for the new conditions. That's why it's important to transplant into S/H right when new roots are emerging from the base of the plant, so they have the opportunity to grow and support the plant.

3) Referring back to my first comment, I have never said that dendrobiums don't do well in S/H culture. I have repeatedly stated that I cannot grow them that way. Others have told me they are ideal for the cultural method.

4) Nobile dens and other plants that require a "rest" are fine in S/H. You can either stop watering, as you would in traditional culture, or water it normally, but provide absolutely NO nutrition during the rest.

5) Your description of a "cold" winter concerns me. Most orchids like it reasonably warm, so if the air temperature is too cold, and the humidity is low, the evaporative cooling from the moist, open medium can lead to excessive chilling of the roots.

[Tindomul]

Originally Posted by Ray

5) Your description of a "cold" winter concerns me. Most orchids like it reasonably warm, so if the air temperature is too cold, and the humidity is low, the evaporative cooling from the moist, open medium can lead to excessive chilling of the roots.

Ohhhh!!! This explains the damage to my Phal after I moved it to S/H. I am so thick sometimes. Thanks Ray!

Excellent post!

[flowerpower]

Thanks Ray! The room is cool in winter. It dips to 18C at night (64F) but is warmer during the day. I could move my plants but it would greatly reduce the sunlight they receive. The humidity is currently 67% with no additional measures to increase it. Where the UK suffers with a lack of sunlight it does have humdity - perhaps this will mitigate the evaporative cooling.

I will update the thread as time goes on to chronicle their progress. I will photograph any signs of improvement or deterioration. I am hoping for plump pseudobulbs one day!

I do worry about losing the roots. It is my biggest concern about the method. At least they are sympodial and have their backbulbs to lean on when times are hard. My yellow rootless oncidium really turned itself around by growing the new pseudobulb. It was once a little wafer sending out a new growth. The peculiar thing about this particular orchid is that, regardless of where it sits on the table, the LECA is always dry at the top. This is not the case for the others, the LECA wicks all the way and feels tacky and cool at the top. It also has a shiny look to it when moist but this one is dry at the top. Same LECA, same pot. I can't explain it, but it seems to be doing fine so I don't worry about it.

I have considered drying them for a day or so here and there just to make things a bit easier for them but I know that would not be correct S/H. I have not done this (except for the dens) but was considering it to slow down root loss while they get going...? Not sure about that.

My other thoughts regarding the dendrobiums: as semi-hydroponic roots will be replacing the existing roots. Would these new roots survive with an empty reservoir next year? I am keen to give them a dry-ish winter - as they will be relatively warm indoors. I have seen some literally covered in keikis. One or two is fine but on every node is too much!

[estación seca]

Looks good.

Go to an Asian market and find some very inexpensive plastic chopsticks to use as stakes. They come in several lengths. You can leave those inside your containers.

Nobile type dens need very cool temperatures and withholding of fertilizer to bloom. No fertilizer after early August northern / February southern hemisphere. 18C / 64 F is not cool to them. They are hardy down to near-freezing. Cooler is better for flowering.

"If kept dry, these species and hybrids will survive winter temperatures of 37-39 F (3-4 C) and will flower around April."

[Ray]

I really don't understand why folks shy away from constantly wet roots, if it's done right. Many orchids experience that in nature, and if that was problematic, they'd be extinct.

[flowerpower]

I wanted to update my S/H experience thread. I still have my 4 oncidiums in semi-hydro and my 2 dendrobium nobiles. I think it is nice to have a diary of the process and help others decide if this is what they want to do or not.

First up, the Aliceara Tahitian Dancer - with the dual flower spikes.

The flower spikes are painfully slow to develop but we are getting somewhere! Bulbs stayed nice and full. This is the one that "sits" on the LECA as it has lots of short little roots.




This orchid, as I said earlier, is so forgiving. I have disturbed it so many times and it doesn't shrivel. It loves water and gets accordion pleating if it doesn't get it. The new growth looks smooth. You can see the pleating on the summer's growth a bit better here:



Here, I move some LECA aside to take a peek at the roots. This plant is tolerating the S/H and I am fairly pleased with the roots under the LECA.



Another side:



Overall, this plant seems to love S/H and I will be keeping it as it is for the longer term.


Oncidium dancing lady (yellow generic one)

This is the one that was rootless when I got it and produced a new bulb. Old bulbs wrinkly due to being unable to take up any water. The new bulb looks great and has started a new growth since I started the thread last month. It has decided not to bloom at the moment. I am not disappointed. Instead, I am grateful that it is still alive because I didn't think it would make it.

I thought it might not take as well to S/H as the bulb was quite mature when moved over and ideally I would have done it sooner. I have since put this oncidium under CFL lights to give it a bit of a boost this winter.



I am very optimistic about this plant as the new growth will bring new roots that will help it adapt to S/H!

Let's look at the roots...



The root at the front is really gripping the LECA bead and looks great. A few roots look a little "dark" but I think this is a little bit of algae not rot. I am seeing some branches coming from them so I think they are OK for now (I might lose them at some stage though). The bulb is still sending a new root down as you can see.

I am very pleased to see this older root doing well.



This plant is harder to gauge because it had so few roots to begin with. The few roots it did have were strong and recent and the plant seems to be tolerating semi-hydro. I am going to continue.

Now, my two larger rooted oncidiums with the big roots.

The first is a Colmanara hybrid. This fell apart into two pieces (potted together) each with a new growth, so it's doing its best.

They were potted into S/H at an appropriate time and I am pleased to see new roots forming.



However, you can see there was some root loss:



The other NoID oncidium is similar. I feel it has plumped up slightly but I am never sure so I like to photograph them.



Roots - again a bit of a mixed situation but the new roots are keeping me optimistic about things.



I will keep all four in semi-hydro in the longer term.


Dendrobium nobile hybrids




This isn't really semi-hydro (yet). I have them in LECA with an empty reservoir. I have just been spraying the roots and the leca here and there when looking very dry. I plan to do the full conversion in spring.

Overall, I feel none of my oncidiums are struggling in this method and I would like to convert more orchids in spring. I am tempted to dabble with phals in semi-hydroponics but I am slightly intimidated - sympodials are much more predictable in terms of growth patterns and when to expect new roots. I do not have an eye for when a phal should be converted.

I have since moved a cattleya and a phal into LECA with a traditional watering system. I love the media. It absorbs enough water but is also airy. It is perfect in my conditions. It dries more evenly than bark and is inert.

I am encouraged by the results so far. I am not complaining about any root loss. I expected it and I am just documenting to what extent it has occurred. I am pleasantly surprised it is not worse.

It has remained a really easy way to maintain my plants and I have enjoyed it. Watering is easy, especially for thirsty oncidiums. I also find it quite fun to flush the pots. I have not really got algae around the pots but it may come.

I had a mild "fungus gnat scare" where I saw a few adults (not many). They seem to be gone now though. I have not seen anything for weeks. I have been poking around trying to find larvae/adults and I haven't found anything. They seemed to be attracted to the S/H water but luckily the inert media came through for me - otherwise I'm sure I'd have a problem on my hands with organic media!

[flowerpower]

I've decided to add more orchids to my semi-hydroponic experiments. I am very pleased with the method so far and would like to see how other orchids react.

Bifoliate Cattleya
This bifoliate cattleya is just some rootless backbulbs that I am trying to propagate into a new plant. One growth is rooting and it has another little growth appearing so I felt it might be fun to see how it does. I have lots of copies of this plant that I bought to use as practice plants (I got them on clearance).



This is the parent plant in bloom. It has a lovely fragrance. I enjoy growing cattleyas so much. They are so resilient that I'm sure things will be OK.




Phalaenopsis
I mentioned earlier my uncertainty about phals. This is because I find them... well... let's just say I find them difficult to grow. They do spike but the root systems leave a lot to be desired. I am interested to see their reaction to S/H. I was hoping to wait until spring/warmer temperatures, but there was just so much root rot going on that it couldn't wait.



- The photo above makes it look like the pot is huge but it isn't - I just need to gently wiggle it more to the middle when I flush it. The roots are not as good as they seem in the photo - there is little below the media.



Both are spiking. I will probably leave the spikes alone for now and see what happens. I hope it is not too gruesome when the old roots die away as they're so thick and fleshy.

[estación seca]

My experience has been that Phals take to S/H well and almost instantly. Keep them warm.

[flowerpower]

Estacion Seca and Ray... I think you both gave me a light bulb moment about all this root rot in my phals. They must need more warmth. No wonder they are all spiking like crazy. I don't know why I didn't connect the two sooner. Luckily in summer it gets nice and warm. So...

I've turned up the thermostat and positioned the phals closer to the radiator with my temperature monitor next to them so they stay warm. Humidity is OK. I've also got a seaweed product to spray on them and add to their reservoirs when I next flush. It isn't Kelpmax but it seems like a similar product. I found it when I went orchid shopping today...