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 Orchids
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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 rot. Also, the cool winters “common phals” need to stimulate spikes is a perfect storm for fungal and bacterial rot if the roots are also wet. Conversely, the summer-blooming phals that need evenly-moist and warm conditions often struggle if a grower’s climate is dry because the top of the pot and base of the plant (where new roots emerge) are simply too dry. If this sounds like you check out this post on advanced phal care.
  3. The nature of using strictly inorganic media removes the grower ability to custom-tailor the drying rate to the needs of the orchid and the climate. Experienced growers know that using organic media in combination with inorganic media, gives them the ability to regulate the drying-out rate of the potting mix (and roots) by altering the ratios of things like sphagnum moss and bark to structure providing inert materials like perlite, pumice, and leca.


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 method (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 action of flowering do 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 LOVE IT.
Plants plants plants plants...ORCHIDS, ORCHIDS!! Thank god it's nearly spring! #plants #orchids #growAreas

Today, after abandoning semi hydro, my orchids are thriving. Of my 50+ phals, I had over half of in spike at the same time this fall; the other half are summer bloomers. But let me tell you…Flowers. Flowers everywhere! My oldest phalaenopsis is a behemoth with over 16 leaves! In fact, of all the phals I have, they only dropped 3 or 4 leaves TOTAL (like out of all of them) for all of 2017! I’ve since learned that leaves on orchids should last multiple years. And guess what—the roots on my plants are EVERYWHERE! It goes without saying that they reward me with blooms on regular intervals, blooming at least once a year, but many at least twice or three times each year. This year, I even dipped my toe into deflasking orchid seedlings and now I have about 100 little novelty phals progressing along nicely.

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. Wet is not how orchids (excluding Phragmipedium) evolved to grow—most orchids come from areas that have wet/dry cycles. That’s why their roots have adapted to suck water up quickly and store it for a period of time. You see the problem is wetness favors conditions that allow bacteria to multiply and fungal spores to germinate and infect your plant—those are not conditions where an orchid will thrive. Those wonderful roots that have evolved to hold water are also remarkably susceptible to infection under the wrong conditions–wet conditions. At that foundation level, it seems to me that always wet cultural methods just don’t make sense as a viable option, simply because they go against what your plant is used to AND they can encourage pathogen growth/infection.

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. And because I was reusing water, the pathogen spread across many plants.

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 10L jugs of distilled water (4-6 jugs/month) and packing them in to my house to water my plants. I would add special fertilizer for pure water, but buying 40L of water at $10/bottle adds 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 it spread rather easily considering I wasn’t dunking the pots in a vat of water that everyone got. Still…shame on me, right?

Maybe so, but the issues you may face can go far beyond just this. Here are some other common issues one may experience when growing your orchids always wet…

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

  • Fungus + Bacteria: Yup, beating this dead horse again. 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”: Yeah, your orchid has to “get used to” the new conditions–often taking 6 months (or more) to get the “right roots”. This potentially sets your orchid growth back over a year, and further to that…I don’t experience this anymore. When I get a new orchid, I repot it and it literally doesn’t skip a beat.
  • Old Root Die Off: Older roots die (because they go from the old medium to a wet medium allowing bacteria to spread, infect and kill the non-acclimated roots), 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. Note: It also 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 “orchid growing success”. This never fails…because 90% of the time orchids growing like this are suffering. I have occasionally been proven wrong…actually only twice was I proven wrong.

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.

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?!”