This is another appreciation-post on how awesome semi-hydro/ LECA can be.

Today, I want to show you how my propagator dome works and how to build one for yourself very easily!

TL;DR

• It uses inorganic media like expanded clay pebbles, Seramis, pon, perlite, or whatever you choose.
• You fill small modified cups with the media and then place your seeds or cuttings in them.
• The media is completely inert and can be sterilized, so you don't have to worry about mold, fungus gnats, or whatever!
• You can't over- or underwater it, it's always moist, but very well aerated.
• This is my personal aerocloner-killer!

Why I build it (backstory)

I've always had trouble getting seeds started, especially for soil plants. They almost always got moldy and the success rate was low, especially due to waterlogging. And because I didn't want to mix soil with hydroponics, I had to search for an alternative.

Some people use rock wool for that, but I always found it too expensive and impractical.

Propagation via cuttings has also been hard for me. Like most people, I started with just a glass of water, but this very often caused rotting due to a lack of oxygen.

So, I built an aerocloner this year. This is basically an aeroponic cloning unit, where cuttings are placed in, which get sprayed with small droplets all the time. It worked really great, but my main issue with it was the noise. It needs an air pump running 24/7, which I found annoying.

I also needed a separate dome just for seeds, which feels redundant.

Many people also just place their cuttings into peat or coco, and they root very well too, as long as they get enough oxygen.

How it works

All semi-hydro substrates have some intrinsic wicking capabilities due to capillary action. This means, that if they stand in water, it gets drawn up all to the top, making the whole medium moist.

In between (and IN) the beads is a lot of empty space. Media like those can only store 30% water or so in their pores, and the rest is air. Air the roots need to breathe!

This means, that the LECA is always wet, but never water logged or compacted like coco, soil or other organic media can be!

Advantages

• Inorganic media are inert, they don't decompose or get eaten by mold or bugs
• As long as you refill the water in the tray once a week or so, you don't have to worry about too dry conditions, both the substrate and the air humidity. And even if you forget to water, it will stay moist for more than a few days after it has run dry.
• No waterlogging (anaerobic conditions due to overwatering) possible.
• Roots are already adapted for both soil AND hydro environments.
• No fungus gnats or other bugs, because they can't eat or live in the hostile substrate.
• Added stabillity for cuttings.
• No spillage, no mess.
• The LECA beads are very easy to remove without harming the roots.

How to build it yourself and use it

What you'll need

• A humidity dome/ seedling starter (available everywhere)
• A bright spot, e.g. your grow tent or windowsill
• (Optional: heating mat)
• A few small cups with lids, optimally made out of HDPE or PP
• A nail, lighter and something for holding
• Destilled water
• LECA or another medium. I like LECA with a small size (4-8 mm) the most for this use case, especially for cuttings.

Preparing the cups

• Separate the lid from the bottom
• Heat a nail and melt a few holes into the bottom. They can be very small, and 4 are sufficient. Try to make the edges as smooth as possible. Too many holes can make removing the roots harder.

• Burn a hole into the lid and but a section off. Otherwise, it will be hard to remove.

• Fill it up with your medium
• Turn it around, take your cutting and push it into the hole while shaking lightly. That way, the stem will just slide into it without effort. Turn it again and give it another small shake. The medium is now locked up and the cutting can't move.

How to use

• Moisten the LECA with a spray bottle. If they are dry, the wicking won't work as great or will take longer.
• Try to water the tray, not the top of the substrate at first. Fine seeds might get washed out otherwise.
• You can just sow the seeds directly onto the substrate and put the lid on it. As soon as they germinate, the roots will "burrow" themselves very lightly into the pores of the hydroton and be fixed there.
• Some heating from below with a heating mat is beneficial

Here are some pictures of a cactus (right after germination) and some cuttings (Tradescantia, hops, Ctenanthe) I made just a few days before:

One thing that always gets told is "Hydroponics is very clean and doesn't need microbes".

Sure, mycorrhiza shouldn't play as much of a role in hydro as it does for soil. The plants get all their nutrients directly from the fertilizer, and waste products should get flushed out regularly.

But, especially in the beginning, I always had trouble with root rot. Besides leftover organic matter and insufficient aeration as possible culprits, I think not having well established beneficial bacteria/ fungi was one reason the pathogenic microbes took over and killed almost everything in the container.

To counteract this, I recently bought water soluble microbes (a mix of dozens different fungi and bacteria) and tested them, especially in semi-hydro.

I'm not sure if it had any effects. For the already established plants, the effects were way less significant than for new ones.

One thing I definitely noticed is the very pleasant "earthy" smell, similar to a rainfall in the summer, when I stick my nose into the substrate.

And, those plants, where the roots got damaged (e.g. my ginger where I continually harvest, or recently transitioned plants with leftover soil) got some fungus gnats. Really not a lot, just here and there one or two, but there are some! They also disappeared a few days later and didn't multiply.

The thing is, many hydro growers put A LOT of effort into keeping everything very clean. Some even proposed to include the ORP value (oxygen reduction potential) just as much as pH and EC, because it tells you how hostile the environment is to microbes and/ or how well stuff can decompose.

I just don't know how I should keep my setup THAT clean outside. It's just normal for me that small insects, leafes and other stuff fall into my reservoir.

And this litter needs to decompose somehow. And I'd rather have it decomposed by a well established microbial culture than some pathogenic stuff that lands on there.

Am I just messy, and I should take hygiene more seriously, or is this totally fine? What's your point of view on this topic?

I've become a huge fan of semi-hydro over the past year.

I've planted all of my 50 house plants into LECA (expanded clay pellets) or pon (special gravel mix consisting of lava rock, pumice, and zeolithe), and they're doing absolutely great. (Too great if you ask me. They've become a weed in my apartment 😁)

Recently, I got into carnivorous plants.

Literally everyone is growing them in turf/peat or moss based substrates, and nothing else. As we all might know, those substrates not only attract pests (fungus gnats, etc.), but are not that great for the environment.

This is why I came up with the idea of using hydroponics.

As soon as I began researching, I've come to the conclusion, that there's sadly pretty much no overlap between the hydroponics community and carnivorous plants community.

So, I started an experiment.

I've put my just-bought Sarracenia, previous in soil, into pon with a very small grain diameter. This keeps the plants very moist, way moister than LECA would, at least the big marbles.

I soaked the granules with distilled water a few times, and then added a drop of diluted phosphoric acid to a pH of 4,5 and EC of 0,1 mS.

This is how the roots look after not only one week:

And the plant itself:

Pretty good if you ask me!

Sadly, Sarracenias need to hibernate, and this one started going crispy even in the store, which is apparently normal, so I've put it into my cold garage for a month or two.

I also started growing Drosera and Sarracenia from seed, but they didn't germinate yet. I got a lot of different seeds from a hobbyist, but growing CPs from seeds is a huge pain from what I've read.

Here's a picture of my seedling/ cutting station: I will make a post about the station soon!

I also sew a few of them directly into the pot and covered it with foil.

In theory, the combination of fine substrate with high water level should provide the plants with enough moisture, while also letting the roots get exposed to a lot of oxygen, which keeps them very healthy.

But swamp plants are just different maybe, I don't know. Let's see...

And, last but not least, I bought two Nepenthes a few days ago. I already placed one of them into LECA (8-16 mm).

They apparently grow similar to orchids, and not like swamp growing plants like venus fly traps or Drosera. So, they rather need a airy substrate, normal pH (about 6) and even tolerate fertilizer.

They looked like this when I bought them:

I will keep you all updated!

Tags for search engines: LECA, hydroponics, hydro, semi hydro, carnivorous plants, VFT, Sarracenia, Drosera, Dionaea, Nepenthes, fertilizer, experiment, inorganic media, peat alternative, pumice, Seramis, pon

I have been contemplating to set up a small vertical hydroponic system, but I am struggling a bit to come up with plants I would actually like to eat that would fit well.

Stuff like tomatoes or pepper just seems to grow way too big to function well in a typical vertical setup, and I am not a big fan of leafy salads to eat.

I found a nice small cabbage (Japanese Tatsoi), which is quite ok, but other suggestions would be welcome.

I bought a few bulbs two weeks ago and planted most of them into LECA (indoors) or soil (on my balcony), but also one into a Kratky pot.

I don't think I can harvest this year yet, but we'll see.

In this one also grows garlic and strawberries. It's meant to hibernate this winter, and then in the early spring, I'll place it outside.

I want to present you my setup I "invented" myself. You can imagine it as a recirculating drip system, but mixed in with semi-hydroponics and a wick setup. And all of that completely "passive"!

How it started

Initially, I wanted a completely passive wick system. I'm a really big fan of passive hydroponics, e.g. the Kratky method or LECA (semi-hydro). While I also like DWC systems and all those others too, they almost always need access to the power grid.

So, I built my wick system myself and transplanted one of my plants from a DWC system into the passive wick system.

By doing that, I damaged quite a lot of roots, and that, in combination with lots of debris from the environment (seeds, leaves, etc.), and stagnant water, caused anaerobic conditions. It smelled horrible, and the plants looked very sad!

Adding peroxide daily and changing the water every few days didn't help. I had 3 identical systems, and all of them behaved the same.

There had to be some kind of oxygenation!

When I was able to flush it all out somehow, everything worked again as it should be after a few weeks. There was no more smell, the pH stabilized, and everything was fine.

Then, one more problem showed: the wick wasn't strong enough. When it was hot outside, especially my hemp plant (lots of surface area, high water demand) looked very thirsty.

It was also hard to adjust the solution, the whole system was very inflexible.

So, I had to make an upgrade!

The current setup

My current drip system is almost the same as the wick system before, but with an added water pump and drippers. You can see the schematics in a second.

How it works

When it's sunny (and hot!), the plant needs way more water. Gladly, we have our solar panel. As soon as the sun comes out, the pump turns on and feeds the plant.

And when it's really hot, the big surface area of the substrate below cools down the roots by evaporation, so they are always optimally saturated with oxygen.

Because the nutrient solution is constantly moving, it doesn't need to be additionally oxygenated with an air pump. The LECA or lava stone is so porous, that it traps just enough oxygen, and the high surface area allows beneficial bacteria and fungi to settle. If any organic debris falls in (insects, pollen, leafes, etc.), it just gets eaten by the microorganisms. I changed the nutrient solution rarely, and it always worked fine.

In the night, or cloudy days, the pump is off. Then the plant feeds itself from the moist clay balls or the wick below.

And, when it's rainy, the rain washes off all salts from the minor crust that has built up.

What's also cool is that you can just remove the plug from the end of the tube and then flush the reservoir or take a sample to check the EC and pH.

Schematics

1. Outer container, holding the nutrient solution
2. Inner container, holding the substrate and the plant
3. The Wick, drawing up water and filtering it
4. The substrate (LECA or lava rock)
5. USB-powered fountain pump
6. Solar panel with USB ports
7. Tube with holes or drippers
8. Optional: a water level indicator and some cover plate against direct sunlight

How to build it

• You need a big plant pot as the outside container, and a smaller one that fits right in.
  I got mine from a local nursery, the pots are literally everywhere!
• Now, you drill or burn some holes into the inner pot. I recommend adding them not directly on the bottom, but a few fingers spaced above. That way, the nutrient solution can form a small puddle, that feeds the plant and keeps the substrate moist, even when there isn't any sun for a few days. I did both and both worked fine.
• Now, add a wick. I used a kitchen towel made out of polyester. Don't use cotton! Any organic material will rot in a few days!
• Then, fill it up with your substrate. Lava rock is cheaper and gives the plant more stability, but is very hard to wash off and can damage the roots. LECA became more of my choice, as it is very easy to clean, is more lightweight, and draws up moisture better, but is also more expensive and provides less stability.
• Add the pump to the reservoir, and make your dripping tube. I bought special sprinkler-drippers, but you can also just pierce some holes into the tube. I did that in the beginning too, and it worked fine. The pump is a cheap one (7€) from Amazon/ Pet supply store, and the sprinklers are bought dirt cheap.
• Add some cover to the surface. I didn't notice much algae build up, but even if those aren't a problem, too much direct sunlight might evaporate too much moisture, and leaves fall onto the substrate.
• Finally, plug in your pump into the solar panels. The solar panel is bought from Amazon, and is pretty inexpensive. Make sure it is water resistant! Ideally, the maximum power generated should be double of the pump.

I don't recommend buying a pre-made solution with the combination of pump and solar panel. I already saw quite a few of them in my garden center, but they are absolutely not modular. If one part breaks, you have to replace the whole combination.

In total, the setup is pretty cheap, at least for home use. I used it for this grow season and I already bought parts for a few more next year!

Pros and cons, compared to other systems

Pros

• Doesn't require "sterile" conditions, not as much as other systems.
• Absolutely great for bigger plants, e.g. tomatoes, cannabis, peppers, etc., as the substrate gives a lot of stability for the roots.
• Doesn't require electricity/ power from outside.
• Very reliable. Even, if the pump or anything else breaks, it won't end in a total disaster.
• Silent. Almost all systems that use an air stone or spray nozzle generate a lot of noise, this one doesn't.
• Easy sample taking. Just grab a jar, remove the plug from the tube, fill up the jar, measure your EC and pH, and done. No need to disturb the roots or lift a lid.
• Lightweight. You only need enough water for the pump to cover, and the LECA isn't dense.

Cons

• You need to clean a lot of LECA in the beginning.
• Slightly higher starting costs. Hydroton is expensive, and you need the pots, pump and solar panel. But, it's also not much more expensive than other systems.
• If you have a slug infestation, like I had, it is horrible! The moist clay pebbles are the perfect home for any snail. If they die, they leave a lot of biomass and dirt.
• Hard to check the water level and root health. In my DWC, I just lift the lid a few cm, here it's harder. You'll notice when the nutrient solution is empty, because then the pump will run dry, and it becomes loud, but the water level indicator is a thing that I will definitely add next year.

"Indoor plants not only add a touch of greenery to your living space but also purify the air and boost your mood. While traditional soil-based planting is popular, growing plants in water, known as hydroponics, is gaining traction due to its simplicity and aesthetic appeal. In this guide, we’ll explore which indoor plants can be grown in water, how to care for them, and other useful tips for successful hydroponic gardening."

cross-posted from: https://slrpnk.net/post/12178994

For those of you who are doing hydroponics, what do you think of this system? Is it a good system for a beginner on a budget? Or is there a better system?

I have recently started playing with hydroponics in my balcony. I had success with jalapeños in a simple bubbler setup. Also tomatoes worked great in an ebb and flow system. Basil works, coriander is a bit iffy, dill does not grow. How do you know what will work and which plants need what kind of nutrients?