Common Misconceptions about Growing in Semi-Hydroponics
There is a lot of information out there about growing in semi-hydroponics and not all of it is correct. What really are “water roots”? Do you really get less pests? Is it sustainable for long term growing? Let's explore these topics.
This post addresses some of these common misconceptions about growing in Semi-Hydroponics.
The first obvious question to this misconception - well shouldn’t they be LECA roots, or pon roots?
What are “water roots”? We assume they are the fuzzy white roots you often see with Semi-Hydroponics growing. In reality, calling them “water roots” doesn’t accurately describe what is happening and can lure us into a false sense of security about transitioning plants.
Have you ever transitioned a water-propagated plant into LECA and it rots out, and it leaves you super confused? Yup, this happens - read on.
Instead of thinking in the soil vs water duality, let’s think about roots as adapted to LECA, adapted to Pon substrate, adapted to water, and adapted to moss (eww). That’s basically what you’re doing when planting in any medium - you are encouraging your plant to adapt to the environment. Once we adjust our thinking, we can start troubleshooting why that water-propagated plant suddenly declined when you put it in LECA and stop proclaiming “but they are water roots!”
When you take a cutting and propagate it in water, you are encouraging the plant to grow roots that are adapted to a water environment. When you move it from the water-environment to a LECA or Pon environment, you are still changing the environment. When a plant’s roots change in environment, they may not adapt.
Think about it in these terms:
Some plants are more adaptable than others to new environments.
Pothos struggle to adapt from a soil environment to a LECA environment, but they adapt easily from a water environment to a LECA environment.
It’s easier to propagate an aglaonema in a water environment than a LECA environment.
It’s difficult for Hoyas to adapt from a moss environment into a LECA environment, and it’s easier to reroot straight into a LECA environment rather than forcing it to go from moss -> water -> LECA. (Although it will probably do just fine because it’s highly adaptable).
Changing your way of thinking will help you to better tailor how you transition plants (and give advice to other people). You don’t have to ALWAYS propagate in water and then move to LECA. Although if that works for your environment, keep doing what’s working. At the end of the day, your environment is likely different than mine, what’s easier for you may be harder for me. Keeping the “water roots” misconception in mind can help you tailor your transition strategy to semi-hydroponics, and I will always advise you to find the easiest methodology because no one wants to baby their plants through multiple root environment transitions, right?
Sorry to break it to you, this is sadly not true, you will get pests. However, some pests are less likely to thrive in the absence of organic medium. There are also different ways to treat pests when you grow in LECA to make treatment and prevention easier.
In this section we touch on types of pests when growing in semi-hydroponics, pest treatment, and some tips only LECA growers can do easily.
One of the reasons that attracted me to growing in LECA is the elimination of fungus gnats. These pests are annoying, but they’re not extremely harmful and most people who have a lot of plants and grow in soil will eventually experience the annoyance of fungus gnats. They can definitely grow in a LECA environment, by feeding off of rotting roots and laying eggs in the reservoir, but they ultimately don’t thrive in this type of environment because portions of their life cycle is dependent on soil. Thrips also have a portion of their life cycle in the soil, but they can definitely reproduce and destroy a plant in LECA as well. Many pests are foliar based only - they feed, live, and reproduce on foliage only. You will get these pests no matter what medium you grow in. This includes mites and mealie bugs.
We won’t get into the nitty gritty of pest treatment - most treatment options that works on soil-grown plants will work on LECA and Pon grown plants with a few exceptions. You can use foliar sprays like normal. However, if you want to use systemics or anything that would typically be sprinkled onto the soil, you will want to avoid those products and use a product specifically made for hydroponics. My go-to is General Hydroponics Azamax, it can be used as a systemic and foliar spray. Read mixing instructions carefully to get the right dosage for the right treatment method. My favorite bug-zapping arsenal also include Captain Jack’s and Safer brand Pyrethrin + Insecticidal Soap. Between these three products, I can effectively treat mites, thrips, mealie bugs, and scale bugs.
One quick mention of predatory bugs to treat pests for plants in semi-hydroponics. I’m not a huge fan of this method mainly because I can’t get the guarantee / peace of mind that the predators “got all the bad guys” without continuously releasing beneficial bugs, and this makes it super expensive compared to using chemical solutions. However if you go with this method, word of warning for using ladybugs - they end up drowning in the reservoir quite a bit. They do a pretty good job in reproducing, but be prepared to clean out dead bugs out of your reservoirs and you’ll need to replenish the population every once in a while.
Lastly, some tips for LECA growers to treat plants easily!
The Dunk - This involves taking a plant and shoving it into a bucket of bug-zapping solution and letting it soak for 10-30 seconds, and then taking it out. Soil growers (and even pon growers) can’t do this very effectively because by the 5th plant, your solution will be a muddy / rocky mess. The pro - it covers every single nook and cranny of the plant that you’ll never achieve with spraying. The con - it uses a lot of product - so buy the product in concentrated form, and only use this method for a large infections, or you want to treat all your plants for prevention purposes to avoid waste. My favorite product to do the dunk with is the Safer Brand Pyrethrin + Insecticidal Soap. It pretty much kills all pests on contact (but won’t do much to the egg sacks / next generation). I like to use it with Azamax - which controls the next cycle of pests as they emerge.
Systemic in the Reservoir - product direction for Azamax doesn’t include a “semi-hydroponics” or “passive-hydroponics” set of instructions, so as a grower you’ll have to experiment a bit on how to use this product in a semi-hydro setting. Good thing you are here because I’ve used this product for a while and I can give you some observations.
It’s perfectly OK to leave Azamax in the reservoir for about 1-2 weeks - however if you value a plant, please test it out and observe frequently and not just take my word for it. I’ve left Azamax in the reservoir for 3 weeks too, I saw some signs of dehydration on a few hoyas.
Some have observed that the oil-based Azamax clings to the root system and can cause the roots in the reservoir to rot. I’m not too worried about rotting roots in the reservoir in an NSW setup because old roots can rot and new roots will grow to replace them. If you have your plants in a submerged setup I would observe more carefully because it’s harder to get at those rotting roots in those setups.
I would recommend against using Azamax with your nutrient solution. Mainly because there’s no reason why your plant can’t go without nutrients for 1 - 3 weeks while you put them in a systemic treatment.
I would recommend against using Azamax all the time, or using it at a lower concentration because you really don’t want to brew any super bugs that are resistant to your systemic treatment.
After an Azamax treatment, make sure your next nutrient solution contains probiotics (Quantum Orchid, Hydroguard) to replenish your root zone biome, and a root-generating product (RapidStart, KelpMax) in case you lost some roots to the Azamax solution.
A combination of foliar spray and systemic is the best way to treat pests in my opinion. Keep up a regular spraying cadence along with the Azamax treatment for the lifecycle of the pest. I personally have not used Azamax past 3 weeks in the reservoir.
This is a very common misconception about growing in semi-hydroponics. The root cause is that it’s not natural for plants to grow in inorganic medium, it’s natural to grow in soil. However, hydroponics growing has grown in popularity over the last few decades and it’s a proven methodology in commercial agriculture. So why do we assume a houseplant grown in semi-hydro will just fall over and die one day?
Growing in inorganic medium is different. You will need to learn about some aspects of growing that most organic-substrate growers take for granted - like nutrients, pH and availability, salts, and how to troubleshoot for your plants to thrive.
First of all, stop watching those YouTube and TikTok videos about how people have failed growing in semi-hydroponics. I can think of better ways to spend time in learning about how to grow rather than failure stories. Do we watch videos about people failing to grow in soil where they blame the soil for the failure? No, because no one makes those videos - it’s ridiculous to blame the soil rather than the grower - so why do we blame LECA or Pon as the source of the failure instead of the grower?
It’s true, there will be some plants where semi-hydro growing is not the optimal growing environment. However, there are many factors in this equation of growing a thriving plant, your nutrients, humidity level, light intensity, pests, pH level, flushing frequency, temperature — all factors that can be contributing to your plant not thriving (same applies for soil growing too!). People change their plant substrate too, some claim plants grow best in moss, or best in chunky soilless mix, but organic medium never takes the blame for the decline of the plant - it’s always the inorganic medium because it’s not “natural”.
Finally if you still don’t believe me, I’ll leave you with a few of my favorite growers across the world with lush, thriving plants grown in inorganic medium.
Nige - A grower from Australia with by far, the most impressive and LARGE plants grown in LECA.
Kevin - Canadian grower that has GREAT Youtube Videos and Instagram posts, on top of having an adorable personality.
Melelina - US grower with many orchids and cacti living their best LECA life. She does many growth comparison photos.
Annabel - UK grower and a research scientist - check out her YouTube for some of the best science-experiments around growing in inorganic medium.
Ray - Perhaps one of the founding fathers of semi-hydro growing, he’s been growing orchids for 40+ years, majority of it using LECA.
And of course, you can follow my humble instagram account for (mostly) hoya photos. :D