The Down Side to Semi Hydro (S/H) and Full Water Culture (FWC) for Orchid Care Thinking about jumping on the bandwagon? You might want to reconsider...

In Orchid Tips & Care
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I want all of the orchids to thrive! And after helping countless other orchid growers with their plants, and seeing so many people struggle (and kill orchids) with semihydro and full water culture, I’ve decided it was time to expose “the other side” to these “always wet” growing methods.

What are “Always Wet” Culture Methods?

Semi-Hydro (S/H) or Full-Water Culture (FWC)—what I call, “ALWAYS WET” culture methods—are two ways of growing orchids that are both branded as “the easy way”. In these two growing methods, the roots of the orchid sit in a stagnant pool of water. The intention is to provide the roots and plant with a constant supply of water. You see it’s “always wet“—because the roots are always hanging out in water.

The three problems with always wet orchid culture are: 

  1. Unsuspecting (and new) growers can experience a high failure rate because they assume it’s a care-free method.
  2. Phalaenopsis growers often run into problems with root growth. Why? Because the cool temps that “common phals” need to stimulate flower spikes are a perfect storm for fungal and bacterial rot. Cold + wet roots == not good! Conversely, the summer-blooming phals that require evenly-moist roots and warm conditions often struggle if a grower’s climate is dry. Organic media like bark and sphagnum moss will distribute water and humidity more evenly and can mitigate a dry climate; however, with always wet methods, the top of the pot (and base of the plant where new roots emerge) is harshly dry while bottom is overly wet—the roots of these warm-growing phals in always wet culture often look shriveled and stunted.
  3. Using strictly inorganic media doesn’t allow the grower to custom-tailor the drying rate of the potting mix to the needs of the orchid and their climate. Experienced growers understand that using organic media in combination with inorganic media, gives them the ability to regulate the dry-out rate of the potting mix and roots. By altering the ratios of organic additives like sphagnum moss and bark to the ratios of structure-providing inert materials like perlite, pumice, and leca you can make a potting mix that dries as quickly or as slowly as you or your plant desires.

 

If you’re a phalaenopsis grower, I encourage you to check out this post on advanced phal care.
It’s loaded with good information & care tips for more flowers.

 

I Used to be a Dedicated Semi-Hydro Orchid Grower!

In the beginning of my orchid hobby, I grew all of my orchids in semi hydro (for about 2 years). At the time, I thought I rocked at orchids because they rewarded me with flowers. However, I’ve since realized that the act of flowering does not equate “thriving” or survival; you see, an orchid will flower as a last-ditch effort to save its genetic lineage :(. There were a lot of genera I killed in S/H very quickly; Oncidiums HATED it, paphs survived but never grew, and phals kind of survived but they only ever had 3 or 4 leaves at any given time. In the end, a lot of them struggled and died a long and slow death. I’ve since stopped using semi hydro and have opted for a traditional semi-organic orchid media and I am surprised at how much better my plants look.
Plants plants plants plants...ORCHIDS, ORCHIDS!! Thank god it's nearly spring! #plants #orchids #growAreas

Since abandoning semi hydro, my orchids are thriving. My oldest phals carry anywhere from 10-23 leaves at the same time, and in the fall and spring my growing area is littered with beautiful flowers! Something new that started happening…my phals stopped losing leaves…I didn’t even know that this was possible, but phalaenopsis leaves can last for 3-5 years! The roots on my plants are much more prolific than they ever were, which has a compounding affect of faster growth. In 2017, I even dipped my toe into deflasking orchid seedlings and within 2 years they were blooming!

Photos of my current orchid collection – NOT in semihydro

“Always Wet” is bad for Orchids and GREAT for bacteria and fungal growth in the root-zone.

WHAT??! you ask? Yeah, wet is where bacteria and fungus like to grow and it’s how spores germinate and pathogens spread. Constantly wet environments are not where most orchids have adapted to grow (excluding some Phragmipediums of course) and so they become more susceptible to infection. The vast majority of orchids grow in habitats that experience wet/dry cycles—you know, a rainforest. That’s why orchid roots have adapted to suck water up quickly and store it. At that foundation level, it seems to me that always wet cultural methods just don’t make a lot of sense. 

A side story: When I was growing in S/H, I ended up losing nearly 35% of my collection to what I assume is a fungal or bacterial infection (but very well could have been a virus). Below are a few photos of what I was dealing with. It happened because I was reusing water…not much mind you…but I reuse some and the pathogen spread across a third of my collection, killing all that it infected.

Phalaenopis gigantea - new leaf
Phalaenopis no name
Phalaenopis stuariana - old leaf

Shame on me for reusing water, right?

Well, that was also a symptom of a bigger issue…I was buying ~4 x 10L jugs of distilled water every month. I would add special MSU orchid fertilizer for distilled water, but buying 40L of water at $10/bottle added up pretty quickly. It was expensive and I tried to cut corners by preserving water. As I filled one pot, I would let the excess water drain from one pot to the next. I never transferred the same water to all of the pots. I literally just used the next pot to catch the excess water from the pot I was currently topping up. So the pathogen spread rather easily considering I wasn’t dunking the pots in a vat of water. Still…shame on me, right?

Probably…but let my failure be a lesson for you. I still have more reasons why I really don’t like always-wet orchid culture.

Why “Always Wet” is bad (the WORST) for Orchids:

  • Fungus + Bacteria: Yup, beating this dead horse again (it’s like a bad ex and I definitely have baggage from this one). Baseline concept you need to know: it’s easier to get bacterial & fungal infections in your orchids because you’re creating the perfect conditions (wetness) where those pathogens thrive and spread.
  • The “adjustment period”: new orchids have to “get used to” these always wet conditions—some can take up to 6 months (or more) to get the “right roots”. Those that don’t adjust generally just die…but the ones that do adjust are generally set back a bit. It was a shocker to me, but that adjustment period isn’t normal. I literally don’t experience this anymore…and if I don’t see new growth within the first few weeks of getting an orchid, I know something is wrong. 99% of the time, I repot new orchids and they keep growing like nothing happened.
  • Old Root Die Off: Older roots die because they go from the old dry conditions to new wet conditions that encourage bacterial growth. Old roots often get rot and fall off which also means there’s a lag from when you repot the orchid into FWC/SH and it’s subsequent establishment in the new always wet conditions.
  • Less roots: It seems that orchids grown in water culture tend to end up with less roots overall—likely because the wet/dry cycles that stimulate new root growth…are absent. A lower root count on unestablished plants can easily yield higher rates of death.
  • New Roots Abort: Growers will often experience aborted roots because the material (terracotta – Leca/Seramis) actually starts pulling water from the plant when it gets too dry! That’s a big problem if you live in a dryish climate (under 70%). 
  • Shriveled leaves and pseudobulbs: This happens from dehydration—simply put, when you stop actively watering your plant, it becomes dehydrated. I actually didn’t know this…but Oncidiums ARE NOT SUPPOSED TO HAVE SHRIVELED PSEUDOBULBS! (Same goes for Miltoniopsis—not supposed to have shriveled pseudobulbs).
  • Too Dry at the Top: Too much air flow (large pebbles) which dries out the roots too quickly, or rather it dries out the top layer of the medium while the bottom layer is still wet (terrible conditions for new roots). The water-wicking affect of the leca/seramis only works effectively if you’re in a humid climate and the water has a chance to wick all the way to the top.
  • Too Wet and Stagnant Around the Roots: Too little air flow (small/variable sized pebbles), can prevent air flow to the deeper root zone (not the end of the world, but air circulation through fans or something should be used to force air through the medium…or you really risk rotting your orchid roots).
  • Increase your pH? I have seen videos on youtube that verify that intert substrates can increase the pH of water substantially (into the range of 8.5-9.0)…I’ve also seen videos of people countering this. So the jury is out–admittedly, I don’t really care too much about pH. A story for another post.

But everyone online says Full Water Culture and Semi Hydro are THE BEST…

Yeah, trust me, I’ve heard all the claims too. Here’s the problem, if someone is saying how great FWC or SH is…ask them to share photos of their orchids in in SH or FWC. 90% of the time orchids growing like this look a little rough.

In general an orchid that is growing well and is happy should have firm leaves, good leaf growth (if it’s a phal, more than 3 leaves), numerous flowers (if in bloom) and a good amount of roots. Look for that in the images of the orchids people show you. It’s not a pissing contest…it’s a proof contest. Prove that the growing method yields success, because you’ll find often time it does not.

FWC phals ALWAYS look like they’re on the edge of death…2-3 leaves that are often floppy, 2-4 roots with literally no root growth visible in the water (but often roots growing away from the water), and if the plant is in bloom, it has anywhere from 2-4 flowers (5 if you’re lucky)–NOID phals should generally hold about 7-14 flowers without having to manipulate any major temperature adjustments.

SH orchid sometimes look fantastic…but often times they really don’t—black leaf tips, black spots, bacterial infections (yellow spots or chlorosis) or burnt roots.

I have occasionally been proven wrong…only a handful of times, but in those cases the grower generally lived in humid climate, they grew their plants in a greenhouse, or the plant they have is one that comes from a drier climate where it had adapted to seasonal variations and therefor was better able to mitigate both wet and dry conditions.

Okay, I’m Done Ranting. Choose what works best for you

If you’re having good success with either of the two always wet culture methods, then good for you! This is my experience and observations when watching others struggle with their plants. Further, if you’re curious if it will work—TRY IT! Don’t be scared of growing orchids (or what I have to say), you’ve got to experiment and see what works for you, your lifestyle and climate. This post is intended to help people who are considering S/H or FWC and be a benchmark for people who are already growing in either condition but are suspicious that it might not being as effective as they once thought.

That kind of sums up my thoughts. I will build and modify this post periodically. If you’re looking for help on how to grow orchids, check out this post on growing phals it has all the juicy details that have provided me thousands of happy orchid flowers.

If you’re still planning on growing your orchids “always wet” – Watch this video first


 

Happy Orchid Growing!

“But Dustin, you said proof is in the pudding…where’s your proof?!”