Hydroponics may seem like the plant-growing method of the future— after all, it’s a departure from not only soil, but organic mediums completely. But this method isn’t as space-age as it might look. In fact, Hydroponics supposedly dates all the way back to the hanging gardens of Babylon. But what exactly is it?
Simply put, Hydroponics is a branch of horticulture that focuses on growing plants in an entirely liquid solution. The solution has all of the nutrients that the plant needs to survive, and the plant is suspended over it.
Semi-Hydroponics, which is what we’ll be focusing on today, puts a modern spin on the classic. Rather than depending on a liquid solution, Semi-Hydro techniques employ inorganic solids, such as LECA (Lightweight Expanded Clay Aggregates) as a growing medium, allowing the plants to anchor themselves, while a few inches of standing liquid at the bottom of the container provide moisture and nutrients. This alternative growing method is becoming increasingly popular with plant-lovers around the world, and here’s why.
LECA, also known as ‘Expanded Clay Pebbles,’ are super-heated in a rotating kiln, a process which sterilizes them and gives them their unique structure. Hard and tough on the outside, these little spheres are full of pores and air pockets on the inside, creating a useful capillary function.
The capillaries in the LECA—which are essentially tiny tunnels and openings in the clay—draw in water from the bottom of the container and wick it upward, hand-delivering hydration to your plants with the panache of an Edwardian Butler at a Badminton game. Because of this kicking ability, your plant doesn’t have to dangle its dainty little roots in the water directly, which reduces the risk of root decay significantly. Also, your plant can drink whenever it wants, which removes the guesswork from watering. Simply water your plant when the standing liquid has been absorbed by the LECA, or slurped up by the roots. Goodbye over-watering!
Just like the crucial amendments you might find in a good potting mix, the pores in LECA also provide constant oxygen to your plant’s roots, improving their overall health and minimizing the risk of disease.
In addition to its capillarity (may this word bring you much Scrabble renown) and porousness, LECA is incredibly strong and durable. Sterile and pH neutral to boot, these forbidden Coco-puffs are resistant to decay and don’t break down or compact over time, meaning you can reuse the same materials more than once.
As with any potting medium, your plant won’t have access to all of the nutrients it needs from the soil or potting mix alone. This is especially true when growing in a sterile compound like LECA. In order to provide your plants with the nutrients they need, you’ll need to use Hydroponic Nutrients, or other water-soluble fertilizer.
Creating a Semi-Hydro Setup
While Semi-Hydro might sound complicated, the setup is surprisingly simple, and can be done in one of several ways.
The first, as shown above, is in a glass container. This provides maximum visibility of all the Roots down in Rootville, an opportunity that conventional potting methods don’t provide.
The second, pictured below, is the two-container method. The inner container will house your plant, and is usually a lightweight plastic with plenty of drainage holes at the bottom.
The outer container will hold both your water and your nutrients, so it shouldn’t have drainage holes. Alternatively, a deep plastic tray could be used in place of an outer pot, but that’s entirely up to you. With this method, your plant, sitting pretty in the inner container, can be easily lifted from the water, if necessary, allowing you to clean any residue from the outer container—not so easy to do with the one-container method.
Once you’ve decided which container method you prefer, it’s just a matter of getting your LECA,—which is likely available at your local nursery—your Hydroponic Nutrients, and, if you’re looking to challenge the hardiness of your green thumb, a kit or meter for testing pH. If you’d rather save the pH conversation for another date (no judgment here), try using distilled water for your Semi-Hydro, to maintain that neutral pH level.
What Plants Can You Grow Semi-Hydro?
While this method has been used extensively in the field of orchids, there are tons of different plants that you can grow in Semi-Hydro, whether you’re looking to make the switch from conventional growing mediums, or dabble with some plant cuttings. Here’s a few of the common ones that you can get started with!
- Prayer Plant
- Chinese Evergreen
- Money Tree
If you’re interested in a plant but don’t see it listed here, there are a lot of great resources online that should tell you what you need to know about your plant’s specific needs.
For a detailed look at how to transfer your plants to Semi-Hydro, click the link to read our How to Transfer to Semi-Hydro article.
While the methodology might be unfamiliar as a whole, caring for your Semi-Hydro plant probably won’t feel all that foreign. Because LECA is impervious to breakdowns (jealous), your plant’s root growth can become an inhibiting factor over time. If your roots grow too much, they can start to crowd out all of the space in the pot. This reduces oxygen availability and increases the output of carbon dioxide. When this happens, remove the plant from its container and trim off any deteriorating roots, or, as with any potting medium, transfer it to a larger container where it can continue to grow!
Thanks for learning about Semi-Hydro with us. For more information about this fascinating method, check out our other articles: How to Transfer Your Houseplants to LECA, and Hydroponic Houseplants: How to Grow Plants in Water. As always, tag us in your horticultural adventures @houseofplantlovers, and happy growing!