What Is Semi Hydroponics?

by RightFit Gardens | Last Updated: August 25, 2021

After you got the hang of building a potting soil garden as a plant parent comes a new trend: Hydroponic houseplants! Alternatively, we can refer to this trend as semi – hydroponics. Can houseplants be grown semi-hydroponically? How do they grow? First, perhaps we should ask – why?

Why semi-hydroponically grow plants?

semi hydroponicsFor casual houseplant growers, this method is appealing because it is challenging. It’s a great thing to try after you have mastered the old-fashioned method of growing house plants. It might also be a pandemic project to distract you after being stuck inside for so long.  What are the benefits of growing houseplants in this manner? There are a few.

There is ample evidence that semi hydro cultivation is beneficial for people who struggle with chronic over-or under-watering. Hydroton is a big, porous puffed claystone sold as LECA (Lightweight Expanded Clay Aggregate). A hydroponic system for growing vegetables (and other plants) utilizes it. Creating large pore spaces and keeping water and air in balance helps keep roots well hydrated.

Overwatering is the main cause of plant death – it reduces the amount of air in the inert medium, which causes the plant roots to lose oxygen (called hypoxia) and either die or become damaged. Additionally, fungal infections can cause root rot more easily if the soil is wet. Yet, how do you prevent overwatering plants if they are grown in water?

Epiphytes, for example, might also benefit from having traditional mediums than soil. In their native habitat, plants that usually grow on the bark of trees or in rocky environments might perform better in a medium such as a large, rough pebble that resembles the texture of bark or stones. Many tropical houseplants thrive in areas containing large amounts of organic matter, such as large chunks of wood or bark. Also, plants from boggy areas that require a lot of water or grow in soil that is “mossy” will benefit.

Cuttings can also be propagated using this method. The practice of propagating cuttings in water may be popular with many houseplant growers. Still, this method is not always the best because the water may become depleted of oxygen (resulting in hypoxia and rot) or spoiled or sour (resulting in infections). Plant propagation is typically done with light media like seed starting mix, perlite, or sand. However, it is difficult to keep the water level consistent without overwatering, and media can also serve as a vector for disease. Keeping the cuttings hydrated without relying on water propagation is possible in semi-hydroponics due to the air space and wicking action of LECA media. Because this method is usually done in clear containers, it’s also possible to see root growth throughout the process.

Growing semi-hydroponically, how do you do it?

If you’re interested in learning more, I suggest self-study if we can’t cover everything in this short article. It is not enough to cover the basics; there is much more to learn.

There is a simple form of hydroponic production used by many home hydroponic gardeners called the Kratky method that this method resembles somewhat. Passive hydroponics cultivates plants by suspending them over nutrient solutions. A few inches of the roots can touch the nutrient solution when the plant is planted in the nutrient solution right below it. The roots of a plant grow longer as they grow, and that elongation reduces the level of nutrient water around the healthy roots. By allowing the roots to take up a solution while there are pockets of air around the roots, the plant can avoid hypoxia issues.

Clay balls are used to distribute roots through a semi-hydroponic container.  A young plant or recent propagation makes it easier because there are fewer roots. Smaller plants will also be able to handle the shock of moving from potting soil to this system.

We add the nutrient solution to the container. It is not appropriate to submerge the roots in the solution but rather add it to a level where it wicks up through the media to surround them. As a rule of thumb, you should fill the container with about one-third of the solution, but higher filling levels are necessary if the container is exceptionally large or there are few roots.

One of the trickier parts is the nutrient solution. In many garden centers now or online, you can purchase general hydroponic nutrient mixes. In addition to general houseplant fertilizers, you can choose specific ones for the type of houseplant you want to grow. Since we’re not using soil or organic matter, we must supply all of the plant’s nutritional needs. Add micronutrients along with macronutrients like N-P-K.

To mix the solution, you’ll need to mix it between 1/4 and 1/2, depending on your plant and how it performs. Once you have pH balanced the plain water, make sure the plant can absorb all the nutrients. If you have a plant with specific needs, you may need to adjust its pH between 6.0 and 7.0. Depending on your pH meter or pH test strips, you will need basic and acidic solutions to adjust pH. If you use reverse osmosis or distilled water, this adjustment is going to be easy.

Maintain an adequate level of moisture in the medium by topping up the solution. Hydroponics utilizes nutrient salts at different rates, so you may observe poor growth if they accumulate over time. Performing a flush every few weeks is the best way to prevent this from happening. After draining the nutrient solution, the plant is rinsed with clean water, and fresh nutrients are added.

Growers with more experience may want to consider alternatives to a clear glass container. Therefore, determining the level of the nutrient solution by visual inspection cannot be automatically determined. The most common container used for this is a net pot or a nursery pot with drain holes for watering. As an alternative, you can buy net pots or pot inserts to use with any plastic container. To water them with tap water, pop the net pots out of the containers. You will need to wash the media unless you remove the plant completely or drain the standing water from the container.

In a semi-hydroponic system, what can I grow?

It is possible to use many different plants. There may not be a list of plants for dos and don’ts out there, but you can start with a few of them. A wide variety of tropical houseplants are suitable candidates. Other epiphytes, such as holiday cacti and bromeliads, are also good candidates – think of things that grow on trees or tree bark. Due to their mostly epiphytic habits, Hoya, which are all the rage in houseplant circles, are also candidates. Lots of tropical plants do well in this system, such as Monstera, Philodendron, and Pothos.

If you’d like to try it out, you may want to experiment since there isn’t an exhaustive list. When looking for plants, experimentation can be beneficial as long as it isn’t an expensive plant.


It’s not for everyone to grow houseplants in a semi-hydroponic setup. Being perfect can be a learning curve, especially if you haven’t done well in chemistry class. Although, it may benefit your plants when done properly and can be a fun way to challenge yourself. The supply of hydroponic and LECA equipment is becoming more and more widespread – many garden centers carry it now. It’s a challenge, so if you’re up for it, do it! You might learn a fun new way to grow houseplants.