Semi-Hydro: A Repotting Pictorial

Here is a little guide with step by step instructions and pictures:
By Louis Aszod. Copyright River Valley Orchidworks.


1. Gather your materials.
You will need: an appropriate plastic container, suitable media, a drill, and a plant to repot. For media, we are using fired clay nuggets similar to PrimeAgra. These are roughly 3/4 to 1 inch in all dimensions. Since the principle behind Semi Hydro culture is the same as the principle that rots your orchid's roots when you leave the pot standing in water, choice and size of media is important. As a general rule of thumb, the smaller the media, the finer the porosity, the more water will be wicked up by capillary action and retained. Conversely, the larger the media, the coarser the porosity, the less water will be wicked up and retained. So it's important that you choose a size and type appropriate for the moisture needs of the plant you are growing.

For a container, anything plastic that's deep enough and handy (from the laundry room or kitchen) will do. In this case, we are using a piece of Tupperware I snagged when from the kitchen.





2. Rinse the media to remove any dust and fines and soak it for several hours. At the end of that time period, water the plant thoroughly.

3. Mark the plastic pot approximately 2 inches up from the bottom and drill holes around the circumference. The holes should be large enough to allow excess water to freely drain, yet small enough to keep the media from spilling out:



4. Drain the water from the soaked media, and pour enough media into your S/H "pot" until it covers the holes. You will need to adjust this initial level depending on the root length of the plant you intend to repot.

5. WASH YOUR HANDS THOROUGHLY WITH SOAP AND WATER, then unpot your plant. This is a Phal. seedling we have been growing in Sphagnum, and the roots are in pretty good shape:



6. Carefully remove the old media from around the roots. Repotting is a "shock" to the plant, so be as careful as possible to keep all of the roots intact:



7. Place the plant into your pot. The plant's lowest leaves should be level with the top of the pot, and its longest roots should not extend below the drain holes you drilled in Step 3. Then, fill the pot to the top with the remaining media, rapping the pot against your workbench every so often to settle the media around the roots. The newly re-potted plant should look something like this:



8. Using a dilute fertilizer solution, fill the pot until the liquid runs out of the drain-holes.

9. Tada! You're done. Your plant has now been happily re-potted into S/H, and you too can now say you're a really cool S/H orchid grower.



Add water / fertilizer solution as necessary to keep the water level even with the bottom of the drain holes.

Learn More about Semi-Hydro orchid growing at the OrchidTalk Orchid Forums