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Save Time. Pot Your Orchids Semi-Hydroponically

The Counter-Intuitive Approach to Watering Orchids

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Try semi -hydroponics - simplify orchid care

Do you ever feel like orchid care is just too complicated? Are you done trying to figure out if your orchid does or doesn’t need water? If this sounds familiar, I would like to introduce you to semi-hydroponics.

Semi-hydroponics takes the guess-work out of watering and lengthens the time between watering. This method uses Lightweight Expanded Clay Aggregate (LECA), an inorganic clay pellet that has been heated and tumbled in a rotary kiln.

Discovering semi-hydroponics made watering orchids SO easy

What Is Semi-Hydroponics

Basically, semi-hydroponics means that plants are potted using LECA clay pellets. The LECA hold water and hydrates the plant’s roots. The roots are allowed plenty of air circulation because LECA doesn’t compact.

This sounds bizarre, but I swear it’s true: eventually the roots will grow down into the water.

How Often Will I Need to Water?

Because the LECA holds water, you will only need to water every 2-3 weeks.

How to Water Semi-Hydroponically Grown Orchids

First, flush the orchid with water. This will wash away excess salt build up. Then leave about an inch of water in the bottom of a saucer or decorative pot.

How to Fertilize Orchids Grown Semi-Hydroponically

Because LECA clay absorbs salt it is vital that when watering you allow water to thoroughly flush through the pot. After flushing water add 1/4 strength the recommended fertilizer dosage to the water. Once a month, water without fertilizing the orchids.

TIP: Do not pot your entire collection all at once.Try semi-hydroponics with just a couple orchids at a time.

Patience is Key

It takes time for the orchids to adjust to semi-hydroponics. After potting semi-hydroponically, it took about 4 months before I felt confident that my orchids were doing better, or as well, with semi-hydroponics than they were with conventional potting.

Selecting the Orchid to Try Semi-Hydroponics

For best odds try semi-hydroponics with a healthy orchid, just beginning to put out new roots. The Phalaenopsis is a good orchid to start with. They are robust and are the least expensive variety.

Personally, I just can’t chance sacrificing my healthiest, most robust orchids. What if they don’t acclimate? I admit to using orchids that I feel like have nothing to lose. That way I’m not out anything if they don’t make it.

In fact, right now I’m experimenting with some Dendrobiums on their last-leg that I got on clearance at the grocery store. They had been grossly overwatered at the store. I’ve potted them semi-hydroponically and one is growing new roots! Time will tell if they will survive.

Start Slowly

At any rate, it’s your choice which orchids you decide to pot semi-hydroponically. But, I do advise that you start with only one orchid at a time. Also, you have the greatest chance of success with orchids that are growing new roots.

Instructions

Begin by gathering your materials.

Materials

  • An orchid. I suggest starting with a Phalaenopsis, as they are the least expensive variety. That way if it doesn’t work, you aren’t out much.
  • LECA clay
  • An old colander, for rinsing the LECA
  • Root Stimulator
  • Torch for sanitizing pruning shears or scissors
  • Pruning shears or scissors
  • Liner pot, or net pot. Base the size off of the current pot size.
  • Decorative pot or saucer. As above, base the size of the saucer or pot off the size of your liner pot, but I do think these Pioneer woman measuring bowls are cute if your orchids are on the small side. Or, these bowls, if your orchid is larger.
  • Keep a garbage can nearby
  • Newspaper for easy cleanup.
  • A seed mat to help the roots become established. This is not a must, but it is one more thing you can do to help ensure success.
  • Fertilizer is especially important if you pot your orchids semi-hydroponically.

Day 1

Rinse the LECA pellets and soak overnight. This will maximize the water-holding capacity of the pellets. Add 1 tablespoon of root stimulator per gallon of water.

LECA - semi-hydroponics

The day before potting, rinse the LECA in water until the water runs clear. Once all the red, powdery dust has been rinsed away, soak the pellets overnight in a bucket of water. Add 1 tablespoon of root stimulator per gallon of water.

Day 2

Unpot your orchid. Remember not to re-pot your whole collection. Again, it is recommended that you use only healthy plants to give them the best chance that they will adapt to this new watering method. I’ll admit that I have a hard time with this recommendation.

The orchid I’m showing in this post is a Phalaneopsis I found on clearance at Lowe’s.

potting orchids

When you’re ready to unpot, soak your orchid in water to loosen the potting medium and make the roots more pliable. While the orchid is soaking, spread out newspaper over your work surface. After the orchid has soaked for about 20 minutes unpot your orchid. Pick away all the potting media until the roots are clean.

unpotted orchid

I picked up this Phalaenopsis on clearance at Lowes. The poor orchid has been terribly over-watered and the roots are in bad shape.

Orchid roots

After cleaning away the potting media by hand, rinse the roots in tepid water to further remove organic material from the roots. Using sanitized pruning shears or scissors, snip away dead, limp roots.

LECA for semi-hydorponics - orchids

Next, add a layer of LECA pellets to the bottom of the liner, or culture pot.

Add LECA to pot orchid hydroponically

Place the orchid in the liner or culture pot and begin adding LECA. Shake the pot so the LECA settles and fills in gaps. Twist the pot so that the roots curl down into the pot. Take care so that the orchid roots are covered with LECA, though aerial roots should remain free to the open air.

Semi-hydroponically potted orchid

After potting the orchid semi-hydroponically, you have a couple of options. One option is to place the liner or culture pot in a saucer or shallow dish. Add a bit of water. This is important: make sure the water level is below the orchid’s roots. Another option is to use a plastic outer pot with holes drilled about an inch above the base of the outer plastic pot. A third option is for those who have purchased a semi-hydroponic kit. In this case, add water to the pot below the recommended water level on the watering gauge.

TIP: After potting your orchid semi-hydroponically, it is vital to keep the water level below the roots. Let the roots grow down in to the water.

Four Months Later

Orchid roots - semi-hydroponics orchids

Four months after potting, this orchid is well established. The root is growing down into the water. To help ensure the success of my orchid’s roots, I set the pot on a seed mat. The constant, warm temperature encouraged strong root growth.

Buds galore - orchid growing semi-hydroponically

This semi-hydroponically potted orchid is loaded with buds and the roots are well established. The leaves are still recovering. They could be a bit more upright.

Another Reminder About Fertilizing

With semi-hydroponics, the orchid is in a bit of a catch 22. The only nutrients the orchid receives is through fertilizer. There is no soil. LECA is an inorganic component that will not break down. LECA pellets do absorb fertilizer salts.

To get around this fertilizer salt problem, this is what I do: When watering I rinse the LECA with clean water, without any fertilizer. After the LECA has been rinsed, I add water with 1/4 strength fertilizer to the pot.

ReUsing LECA

LECA pebbles can be reused as it is made of inorganic material. Here’s how EasyGrowHydro recommends cleaning LECA to reuse:

  1. Dry out the LECA outside in the sun.
  2. Pour LECA from one bucket into another in front of a fan. This allows the organic matter to blow away.
  3. Pick out and discard pebbles with a white coating.
  4. Soak in bleach for several hours. 1:10 parts bleach to water.
  5. Rinse thoroughly.

Another method is to use a pressure cooker or an oven to prepare your LECA to reuse.

You Can Do It!

When potting semi-hydroponically, remember to take it slow. Don’t re-pot your entire collection at once. Also, keep the water level well below the root level until the roots are accustomed to growing semi-hydroponically. Caring for orchids is always an experiment. If you are looking for a way to simplify orchid care, this method may be for you.

How to Care for Orchids

Keep reading to learn all the essentials of orchid care

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18 Comments
  1. Sue says:

    Where can I buy LECA?

  2. Debbie says:

    Amazon carries it.

    1. Anna says:

      Yes, I bought my LECA on Amazon as well.
      Anna

  3. Myriam says:

    Very interesting! and beautiful photos, as always… By the way, I really liked the Pioneer woman measuring bowls 🙂 thank you Anna

  4. Kath Lawrence says:

    Leca is amazing. I live in Western Australia, my orchid collection is over 200 & 3/4 of my lovely orchids are very happy in Leca which were oridinally in spag moss. I only have some in bark etc to experiment but Leca to my orchids is by far the best. I have only had orchids for under 3 years.

    1. Anna says:

      Kath,
      Thanks for sharing! Would you mind sharing how you water and pot your orchids in LECA? I’d also love to see pictures. You can email me at [email protected]
      Thanks again,
      Anna

  5. Grateful Ted says:

    Hi Anna,

    Thank you for posting this! I have a question: The orchid in leca is placed into a pot with a bit of water. You go on to state that “To help ensure the success of my orchid’s roots, I set the pot on a seed mat. ” So you put the mat down and plug it in. Then the shallow pot with water and the orchid in a container is in that water, and all of that goes on top of the mat. Is this correct?

    Thanks for what you do!

    1. Anna says:

      Ted,
      Yes that’s right. I set the orchid in the pot (with the LECA) on the seed mat – that is plugged in.
      Thanks for clarifying.
      Warm regards,
      Anna

  6. Sue Knigge says:

    Hi Anna,
    Could the tiny leca pebbles be used for a mini orchid?

    Thanks,
    Sue

    1. Anna says:

      Sue,
      I have used LECA for mini phalaenopsis orchids with stellar results. I haven’t tried mini LECA. If you do try the mini pebbles, I would love to hear how it goes.
      Have a great day,
      Anna

  7. Emma says:

    Thank you so so much for this post! Absolutely a life saver and it really REALLY cleared up so many questions I had going on in my mind! You did a truly spectacular job at simplifying semi-hydroponics and I definitely appreciate it! The semi hydroponic concept and general set up is a pretty simple concept but the actual specifics on how to plant semi/hydro…..eh not so much! It seems like every article almost is just for Rays website (nothing wrong with that) but Rays website doesn’t have everything! I was really trying to figure out how to do the two pot system or pot in a saucer system and you completely cleared that up for me! Big thank you!

    1. Anna says:

      Emma,
      I agree that Rays is a great site. I am glad I was able to help clear up some information gaps. Thanks for reaching out to me!
      Have a great day,
      Anna

  8. Emma says:

    Anna! This was EXTEMELY helpful in clearing up some questions I had about semi-hydro for orchids and I really appreciate it! One question though, on other forums it has been mentioned that using the pots with the slits in The did even (your standard orchid pot basically) isn’t the best idea because it has a tendency to dry the LECA too quickly. Have you found this to be true in your case? Also, any articles on how you prepare/sanitize the LECA for initial potting or to reuse?

    1. Anna says:

      Emma,
      I love your excitement and curiosity about potting your orchids in LECA!
      About the side slits – they haven’t been a problems for me. Most important is to make sure that the orchids have a reservoir of water and to regularly rinse your LECA to discourage fertilizer salt build up.

      Here’s how EasyGrowHydro recommends cleaning LECA to reuse:
      Dry out the LECA outside in sunshine.
      Pour LECA from one bucket into another in front of a fan. This allows the organic matter to blow away.
      Pick out and discard pebbles with a white coating.
      Soak in bleach for several hours. 1:10 parts bleach to water.
      Rinse thoroughly.

      Let me know how semi-hydroponics works for your orchids!
      Anna

  9. Graves Janis says:

    I am throughly confused but happy my phal is doing well. I haven’t watered it from the top since starting it on it’s semi hydo journey! Guess I need to huh?

    1. Anna says:

      Janis,
      If your orchid is thriving, keep doing what you’re doing!
      Best,
      Anna

  10. Kathy Pavan says:

    I had a nightmare of an introduction to s/h. I changed only my phallies into Leca to see how they would react. After 2 weeks I saw dead and dying roots everywhere and the velamen was just sloughing off the roots. I panicked and pulled them all out of their s/h pots and tried to dry them and the Leca in towels. So many of the roots were dead I cried buckets! It was an awful experience. I lost 20 plants. I put the survivors back into the Leca but without the reservoir of water and with more airholes drilled into the pots for drainage. They seem to be ok, but the roots are a brownish colour and look awful. I still grow them in Leca as the medium, but not s/h. Anyone else had a similar experience?

    1. Anna says:

      Kathy,
      Thanks for sharing! Definitely introduce a couple of orchids at a time to semi-hydroponics. Once you have a few thriving, try a couple more, but never your entire collection. My condolences! I wish you’d had a better experience.
      Best,
      Anna

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START HERE to Learn More About Caring for Orchids

Find Out What I Wish I Knew When I First Started Caring for Orchids

YES! THANK YOU!