Now what?
With a few plants transitioned over… how do you maintain plants in Semi-Hydroponics?
Days 1 - 30
The first 2 - 4 weeks can be the most stressful part of semi-hydroponics. Your entire job is to observe the plant and make changes when necessary.
One factor is the wet / dry cycle for the plant. Every plant needs water - a little, or a lot. Every plant needs air - a little, or a lot. This balance is different for every plant - for example, hoyas like to dry out between waterings, and calatheas don’t mind wet bottoms.
The other factor is soil roots versus water roots. When you are first transitioning a plant over, it will likely have soil roots. Your goal is to keep the plant happy enough to signal that it needs to produce water roots in its' new environment, and keep it healthy enough to enable it to grow those roots. These two types of roots regulate air and water differently. Water roots are capable of getting oxygen from the water. Soil roots are not so great at that.
Your goal is to balance those two things during the initial transition period — give the plant enough air and enough water, so that it will develop water roots to take over for the soil roots. Some plants will adapt their soil roots to a constantly moist environment, and some plants will shed those roots entirely and replace them with water roots.
How to Balance?
Leave the plant with a water reservoir (usually 1/4 or 1/3 of the total amount of LECA in the container). This allow the plant to drink up and absorb as much water as it needs.
Leave the plant with no water reservoir. This allows the roots to dry out - mimicking a natural dry/wet cycle. Dry environments will encourage roots to form and extend in search of water.
Shower with water periodically. This method allows you control over when a plant gets water. This method usually is combined with leaving no water in the reservoir, so the plant gets a quick dose of water but dries over the next few days.
Observe the roots. Potting in a clear container for the transition period helps immensely because you have a visual cue from the roots! Once a plant has successfully developed water roots, you can take it out of the pot and put it in something nicer. A protip here is to put the plastic container inside an opaque container. Roots grow better in darkness.
You are controlling the dry/wet cycle to suit the plant and observing its reaction to your action.
Additional “helpers” to maintaining balance during the transition
Flushing - When a plant is converting, running clean water through the LECA is never a bad idea. This removes any additional soil residue and gives the plant a nice drink. This is essentially the shower method.
Physan 20 - This product is used a lot by Orchid growers - it’s a fungicide, bactericide, algaecide, and virucide. I find it effective in slowing down and preventing roots from rotting on not just orchids but house plants as well. As mentioned before, soil roots will decay and most will die, as water roots take over and support the plant. The rotting roots, when in contact with healthy roots, may cause the rot to spread. Physan 20 helps control the spread of rot from unhealthy root structure to the healthy one. One of the reasons cleaning roots is so important is because any dirt that is in contact with the roots will cause excess moisture in the LECA environment and can cause root rot. By applying Physan 20, you are slowing the rate of soil root rot while the plant pushes out new water roots.
Example 1: Monstera Standleyana Albo
When I first received this plant, it had 5 leaves but two showed signs of yellowing from shipping. I left it alone to recover, it lived on top of my prop station on a heat mat, sitting in loose sphagnum moss. After 2 weeks, it lost the yellow leaves naturally and I decided to move it to Semi-Hydro in LECA.
When I removed the moss, I noticed the soil roots were growing new white roots! It must have enjoyed the heat mat. The root system was very robust and growing.
Since this is a pretty high value plant, I wanted to put it in a clear container so I can keep an eye on it’s progress. These Talenti jars are awesome for smaller plants, also the ice cream is delicious!
Monsteras are very tolerant of wet roots and likes water, I used Hydroton LECA as it wicks better and holds more moisture.
After potting in LECA, I filled the container up to the top of the “F in Fudge”, right below that white root, with a mixture of filtered water, seaweed extract, and Superthrive.
A week later, all of the water is gone, and this new root emerged and reached all the way to the bottom of the pot. You can see how fuzzy it is, that is a new water root.
What Happened?
The plant was in a state of root growth when it was transitioned to LECA. This is the best time to transition a plant. These new roots adapt to whatever environment they are entering, and if it happens to be a wet environment like LECA, or even into straight water, they will adapt.
Monsteras are a very tolerant plant. They love moisture and generally doesn’t need the environment to completely dry out before receiving more water. It entered into LECA and adapted right away, this can be observed by the continuation of it unfurling a new leaf and the growth of the fuzzy water roots.
What’s Next?
I can keep the plant in the seaweed extract water for a little longer, or switch it over to a nutrient solution at this point. Keep the container filled up to the F in Fudge. The root that is in water will be fine. It grew into the water, so therefore it will be adapted to the water.
This pothos was an experiment. I trimmed the roots on a few pieces, and did not on a few other pieces. Put all of these in Hydrocrunch LECA and allowed it to wick from a reservoir.
The experiment did not go as planned because soon after this photo, all of the pieces declined rapidly and flopped over. This photo was around day 10 - the trimmed pieces declined first. By day 12, everything wilted.
The soil roots on these pothos do not adapt well to semi-hydroponics. Pretty much 100% of these roots rotted off, and I had to cut all the roots off and water propagate the rest surviving pieces.
What Happened?
My theory is that pothos does not send out new water roots without the presence of a lot of moisture. Combined with the soil roots not adapting well in my environment, it was a recipe for disaster. Remember that our goal is to balance the wet/dry cycle of the plant for long enough, so that water roots develop and the plant can use the water roots to survive. In these 12 days, there were no water roots present. (Which is interesting because if you put pothos directly into water, it usually develops water roots within a week!). What’s even more odd is that when you put a pothos in water, soil roots and all, sometimes those soil roots adapt to the wet environment and they don’t rot! The most confusing part about this plant is that the LECA environment was on the dry side but the roots rotted anyway.
I’m not confident that I can do enough to keep the soil roots happy in this environment for long enough to entice the water roots to develop, or if water roots will even develop in this environment at all. So now when I transition pothos, I always take cuttings and root in water first, then transition to LECA.
Example 2: Pothos
Days 30+
Once a plant is established the maintenance of the plant is fairly easy, and it’s not much different than taking care of a plant normally.
Watering and Fertilizing: See “Semi-Hydroponics Nutrient Water and pH Adjustment” article for nutrient water information. Fertilize at a level that is recommended for your plant. Some plants will need more while others need less. My approach is to mix the nutrient solution at a weaker level and for higher feeders, add an extra scoop of fertilizer to your container to make it easy.
Shower Method: I do not see the point of the shower method once a plant is established in LECA. I always keep a reservoir for all of my plants because it reduces the mental burden of watering for me. I also don’t transition over plants like ZZ, Sanservia, low-water requirement plants because it’s not in alignment with my goals. For low-water need plants, this may be a valid method, but since I don’t transition these plants I cannot comment. My goal is to make it easier, not harder, and I find transitioning these plants over makes it harder for me to take care of them - so I don’t.
Pests: You should have fewer pests than growing in soil. However, fungus gnats sometimes will appear if you use a reservoir + wicking system - they lay their eggs in standing water. What you can do is sprinkle a few pieces of mosquito bits into the reservoir water. As for other pests such as spider mites and mealy bugs, they will still show up on your plants. Treatment is similar to soil plants. I had a few plants with mites and I caught it very early on - but I took all of the plants in that area and did a neem oil dunk - the whole plant, LECA, and the pots, straight into 3 gallons of neem oil solution. The mites never had a chance. (imagine the mess if you had the plants in soil… I’ve done a neem oil soil drench before, would not recommend).
Flushing: There will be mineral buildup at the top of your pot from excess fertilizer and plant wastes. They look like white specks - you may think it’s mold or bugs, or someone painted your LECA. It’s advised that you flush water into the pot to frequently remove these white specks, this process is known as flushing. Some people flush in the sink by spraying water into the pot and let it run through for a while. Some put their plants into the tub and turn on the shower. The originator of the Semi-Hydroponics method advise to flush with nutrient water, every time you water, by filling the pot quickly to the top of the container and let it drain out naturally. In passive hydroponics (The Kratky Method) flushing is not even a part of the setup. I have many thoughts about flushing and I will follow up with additional information later.
Physan 20: I will continue to apply Physan 20 on a monthly basis to keep all the baddies away. However as I learn more about beneficial microbes / fungi, I will likely stop using this product unless necessary.
Repotting: As your plant grows larger, there will be a time where you need to repot it. Remember, LECA is an inorganic material so it will never break down like organic potting mix. General rule of thumb for soil grown plants or bark / moss grown orchids is that the medium should be replaced every 1 - 3 years. With LECA, you don’t have to repot unless the plant has outgrown the container.
Root Trimmings: After a period of time, some of the roots will be in the reservoir whether you use a traditional container or a wicking system. You don’t need to trim those roots unless they are getting in the way. They grew into the water, and therefore they will survive in the water. This is the entire premise behind the Kratky Hydroponics method, allow the roots to grow into the water to wick it up. DO NOT take the plant out of the pot to “check the roots”. Plants do not like their roots disturbed and there’s no reason to continually trim or check once a plant is established. If the plant is exhibiting stress behavior (wilting, drying up) then you can check the roots. Every time you unpot a plant it causes stress, if you are very concerned, use a clear plastic inner pot.
These spray bottles are great to use with your Physan 20 solution. I usually mix up 1 quart at a time, and fill 2 bottles full.
Physan 20. I say to myself - you’re never going to use up this whole bottle! I’m like half way through this thing. Spray it on everything. Follow mixing directions, don’t hurt yourself.
Put some of this in your reservoir water (if using a self-watering wicking pot). The other option is to sprinkle some in your filtered water and let it sit for a day. Then use the water to mix your nutrient solution.
Take a rubber band and tie one of these to your bottle of Physan 20, Superthrive, fertilizer, CalMag, etc.
