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Semi-Hydro ~ What is "semi-hydro" and why do people use this method of growing...

If you want a low maintenance way of growing plants, or you travel/spend time away from home often, then semi-hydro might be the right way to grow!

Semi-hydroponic (semi-hydro) or passive-hydro is where the plant is growing in an inorganic, soil-less substrate with some form of water reservoir that the substrate can wick the water up to the plants roots. Leca, perlite and Lechuza pon are the three most popular substrates when growing semi-hydro because they are porous, making them perfect for wicking up water, as well as allowing the perfect amount of oxygen in and around the root zone (yes, roots need oxygen!). There are so many benefits to growing this way.. but we will touch more on those later in the post.

LECA - Leca stands for lightweight expanded clay aggregate and is one of the most popular semi-hydro substrates around. It is easy to use and can be reused over and over again! Being an in-organic substrate does mean that it contains no nutrients, so these will have to be added into your water when filling up your cover pot or vessel.

LECHUZA PON - or pon for short, consists of 3 high quality mineral stones, zeolite, lava rock and pumice as well as a short term, slow release fertiliser. This makes pon super user friendly as plants will not need to be fed in the first 4-6 months of being planted but will need a regular fertilising after that.

PERLITE - Is used a-lot to mix into potting soil to help create a light and well draining mix, but is also used on its own as a semi-hydro substrate. It is super lightweight and porous, so wicks water well.

All substrates need to be thoroughly rinsed before use to remove dust particles from the substrate. This may take a few goes, but you'll know once the water runs clear.

Leca also needs to be pre-soaked before use for at least 24 hours. This removes any minerals in the leca that could prevent nutrient uptake in your plants in the future. A tad annoying but totally necessary. The perks to using these substrates is that they are long lasting, reusable and cost effective.

WHAT KIND OF POTS DO I USE? More often then not, self watering pots are used when choosing to grow semi-hydro. This is because they consist of a cover pot, which will hold the water as the water reservoir, a mesh or net pot insert which you will plant the plant into with your choice of substrate and some will even have a water indicator, which will show you when the water reservoir is getting low and needs a top-up.

Self watering pot for semi-hydro
Self watering pot - 9cm

Self watering pots are great because the inner mesh pot fits perfectly in the cover pot, making it a seamless look but you can also get mesh pots on their own, and find a cover pot that fits and suits your aesthetic better. You could also use a normal clear pot and drill a bunch of holes in and around the base and sides to DIY your own 'mesh pot'.

The key to semi-hydro setups is allowing the substrate to have good contact with the water so it can wick it up to the plant easily.

Another option is simply just using a glass vessel or jar, filling it up with substrate and then filling the jar about 1/3 with water.

DO I STILL HAVE TO FEED MY PLANTS? The short answer is yes. Inorganic substrates lack nutrients, so these will need to added into your water. You shouldn't have to do this every single time you water but every second or third water refresh should do just fine. I use and recommend Growth Technology Foliage Focus or Complete Focus for semi-hydro, they are one part, complete fertilisers, making them super easy to use.

You will also have do a plain water flush every now and again to rinse through the substrate to remove any excess nutrient build up.


When choosing what plant you want to try in a semi-hydro setup, think about what the plants watering requirements are. I find plants like Philodendron, Monstera, peace lilies, Hoya, Alocasia and Anthurium do really well but the likes of cacti and succulents (including 'string ofs' & 'chain ofs' plants) might not be the best option for semi-hydro.

The great thing about a semi-hydro setup is that plants that require more frequent watering, like peace lilies, have the constant supply of water as it needs it, as long as you keep the reservoir topped up. This can also help prevent the brown tips that plants can get from inconsistent watering.


SOIL TO SEMI-HYDRO: Transferring plants from soil to semi-hydro sounds scary, but I promise you its not once you know what to expect. Once you've removed the plant from the soil you will need to give the roots a thorough rinse with water, to remove as much soil as you can from the roots. You want them as clean as you can get them, without damaging them of course. Once the plants roots are clean you can pot up plant into substrate of choice. One thing you need to know is some of the soil roots will rot/melt to start, as they transition but new roots will soon start to grow. This is totally normal! If there is a-lot of root shed, you may need to unpot the plant, remove all the rotten roots and repot once again.

WATER TO SEMI-HYDRO: Water propagated plants are the easiest ones to transfer into semi-hydro as they already have established water roots and the roots are clean. If there is any algae on the roots, try and rinse as much off you can, but this won't harm the plant if you cannot get it all off.

Basically, once you are all set-up with your plants in semi-hydro all you really need to do is monitor the water levels in the reservior, top up when needed and feed every 2nd or 3rd watering. I find this can vary depending on the size of the plant and their water needs but you soon get to notice who drinks quicker then others *peace lily*

SUPPLIES: You can find leca, Lechuza pon, perlite, GT fertilisers, 11cm & 14cm net pots and 9cm self watering pots on our site if you are interested in giving semi-hydro growing a go.

If you have any further questions, leave them below and I will be sure to answer them for you.


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