While perusing Instagram, you may have come across pictures of people growing plants in what looks like Cocoa Puffs. This planting technique is called semi-hydroponics. If you are interested in trying semi-hydroponics, converting some of your orchids to semi-hydroponics may be a good start.
Some types of orchids can be successfully grown in semi-hydroponic systems. Semi-hydroponics is a planting technique that involves growing orchids in a growing medium and nutrient solution. It is a passive form of hydroponics meaning there are no pumps required to deliver nutrients to the plants.
Orchid care can be complicated, but orchids do very well growing semi-hydroponically. Many home gardeners say they have actually had more success growing orchids semi-hydroponically than with conventional growing techniques.
What is Semi-Hydroponics?
The term semi-hydroponics, which is also referred to as semi-hydro, describes a method of growing plants in an inert medium. The plant obtains its nutrients from a liquid solution containing fertilizer.
Typically, the medium used in semi-hydroponic systems is Light Expanded Clay Aggregate (LECA). LECA is clay pebbles that look similar to Cocoa Puffs. They are made by heating clay to a high temperature in a rotary kiln. The gases produced cause bubbles to form in the pebbles. LECA is pH neutral and chemically inert, which means it will not contribute any nutrients to the plants.
In semi-hydroponic systems, LECA absorbs the nutrient solution and wicks it upward to deliver nutrients and hydration to the plant.
Although not every plant can be grown using semi-hydroponics, many plants can be converted to semi-hydroponics. You may think that keeping plants in water would result in root rot, but this is not the case.
In conventional gardening, root rot occurs when plants are overwatered. The excess water creates an anaerobic environment which means the roots are not getting enough oxygen. Anaerobic environments can also encourage bacteria and fungal growth.
In semi-hydroponics, the dissolved oxygen in the water will ensure that the roots do not suffocate.
Benefits of Planting Orchids Semi-Hydroponically
Switching planting techniques can be intimidating, but there are some advantages to growing orchids in a semi-hydroponic system.
Less Mess
One of the major benefits of semi-hydroponics is the soil free aspect. Some people simply prefer not to have soil in their homes. After all, you work hard to clean and remove dirt from your home!
Fewer Pests
In addition, semi-hydro does not attract as many pests as conventional gardening methods. However, this does not mean you are completely immune to potential pest problems.
Cost Savings
Another great benefit of semi-hydroponics is the possible cost savings. For example, LECA can be reused several times. Before reusing, rinse the clay pebbles thoroughly. Although LECA is an inert substance, it will absorb the nutrients in the liquid solution. Rinse the LECA and soak the clay pebbles for about half an hour. Finally, consider baking the LECA in the oven to ensure they are clean. You can repeat this process until the clay pebbles turn to dust.
Another potential source of cost savings is the wide variety of pots you can use. You do not even have to use a “real” pot. You could use soup cans, ice cream containers, or other similar containers. Just make sure your “pot” is large enough. These kinds of recycled materials could also have a nice bohemian look.
Less Labor Intensive?
Many people claim that semi-hydroponics requires less labor, but I am not sure if that is true. You have to monitor your reservoir for algal growth, change the water on a regular basis, and track the amount of fertilizer used for the plants.
If you are looking for a truly hands-off way to grow your plants, semi-hydro is not for you.
Semi-Hydro is Fun!
Finally, you should try semi-hydroponics because it is fun! In general, gardeners and plant lovers enjoy experimenting. Converting orchids to semi-hydroponics is a great opportunity to experiment with new growing techniques.
Which Orchids Are Good Candidates for Semi-Hydroponics?
Semi-hydroponics does not work for all species of orchids. For example, Oncidiums (Dancing Ladies) and Odonata Blossoms do not grow very well in semi-hydroponic systems. These species are too sensitive to changing water temperatures.
Phalaenopsis, which is a genus of about 70 species of orchids, are good candidates for semi-hydroponics. These are the orchids you typically find in big box stores.
The bottom line is that you should use a plant you are willing to use when trying semi-hydro for the first time.
How to Plant Orchids Semi-Hydroponically
Materials
- LECA
- Pot with drainage holes at the bottom.
- Shears
- Rubbing alcohol for sanitation
- Cinnamon
- Distilled water (filtered tap water can also work, but you should make sure the pH is between 5.5 and 6.5. Lower the pH by adding lemon juice.)
- Orchid fertilizer (the American Orchid Society suggests using a balanced fertilizer such as 20-20-20)
Steps for Converting Orchids to Semi-Hydroponics
Step 1: Clean the LECA
First, rinse the dust off of the LECA. Then soak the LECA for half an hour before using them in your semi-hydroponic system. Set the LECA aside for later.
Step 2: Soak the Roots
After cleaning the LECA, soak the existing roots and potting medium for 15 minutes. This will loosen up the potting medium for step 3 and make it easier to differentiate between healthy roots and dead roots.
Step 3: Remove Potting Medium
Dump the water and carefully remove the potting medium. The potting medium will likely be a bark mix and a sphagnum moss plug.
Step 4: Rinse the Roots
Next, rinse the roots with lukewarm water. It is important that you use lukewarm water because cold water will shock the roots, and hot water could burn the roots.
Step 5: Remove Dead Roots
Then remove dead or decaying roots. You will know that roots are dead if they are hollow or mushy. There probably will not many healthy roots left. That is normal.
Step 6: Cut Back the Flower Spikes
Clip back the flower spikes just above the lowest flower node. Flower spikes have a flatter, mitten-shaped tip and are typically greener than the rest of the plant.
Sprinkle a little cinnamon on the cut. Cinnamon is a natural antibiotic and will prevent diseases from forming on the wound of the plant.
Step 7: Pot the Orchid
Fill your pot 1/3 of the way full with LECA. The clay pebbles should be above the drainage holes. Put your orchid in the pot and fill the pot with more LECA.
Step 8: Add Fertilizer
Finally, mix the fertilizer and add the nutrient solution to the pot. The water should not be touching the roots. It is essential that you keep the water level below the roots until your plant has adjusted to growing hydroponically.
After Planting
Remember that your orchid will likely experience some setbacks while it is adjusting to its new life. The existing healthy roots will probably die because they are not accustomed to living in water. But don’t worry, new roots will grow.
You might also notice some of the lower leaves falling off. This is normal. Resist the temptation to put the plant back in a conventional growing system. This will almost surely kill your orchid.
Other Tips
Here are some additional tips that will help make your semi-hydroponics experiment a success.
Heating Pads
Using a heating pad will help the orchid roots grow because warm water helps roots extract more nutrients from the water. You can purchase a heating pad on Amazon for under $20.
Selecting the Right Pot
Your pot should contain a number of drainage holes. I recommend drilling several holes in your pot because the clay pebbles can shift around and cover some of the holes.
Some people will drill holes in glass pots. However, you should consider using a plastic pot for semi-hydroponics. Glass absorbs heat and loses heat quickly. If you place your plant too close to a window during the summer, the heat could end up boiling the water in your pot. As you can imagine, this is not good for your plant. Using plastic pots can help you avoid this issue.
Remember that you can place your “semi-hydro pot” in an outer pot that is more aesthetically pleasing.
Spray the LECA During the Summer
During the warmer parts of the summer, a significant amount of water can evaporate from the LECA. As a result, the top layer of clay pebbles can grow out easily. When this happens, the baked clay pebbles will actually suck the moisture out of the plant which will kill the plant.
Spray the top of the pebbles to make sure the LECA does not get too warm.
