House plant best soiless mix (Hydo coco)

Hey Everyone,

So last year my house plants all became a breeding ground for fungus gnats. I've now bought some Hydro coco to replace the compost in my house plants. As it is 60% expanded clay pebbles and 40% coco coir can I just plant things such as Calathea or Arabica coffee plant directly into this or will I still need to add anything else? I'm guessing I can forget things like perlite as the clay pebbles are already an alternative?

 

I'm not sure your houseplants will be happy in that.

That is a hydroponic compost, so you'll need to use hydroponic fertilizers as both the coir and pebbles are effectively inert.
i.e. unlike ordinary compost or soil, hydroponic compost contains nothing that is beneficial to plants.
You will have to supply everything the plants need, hence the need for a hydroponic fertilizer.

It's a very different medium to soil or ordinary compost, so the roots of your plants will have to adapt to it, and if they don't or can't they will struggle to survive and maybe die.

I'd suggest putting about 1/2" of that compost on top of the compost in the existing pots.
That will prevent the fungus gnats burrowing into the compost and laying eggs.
I use 1/2" ordinary grit which serves the same purpose.
Fungus gnats are attracted to compost that is always damp, so maybe you're overwatering a little.

 

Two methods we have found effective against the Fungus Gnats for our houseplants, only just starting to find the odd one or two now after the treatment early last summer.

Summit Mosquito Bits (amazon) watered in appear quiet effective though a little costly but you may need to give 2 treatments if really infested.

Also using some normal matches like Swan Vesta and sticking them head down into the moist compost , about 4 or 5 per 4" pot.

Though both should be clear of pets and children etc.

Think if you washed off your existing compost and repotted with new compost and washed pots then used the above to water them in, as even the new compost may have gnats, think you will be free of most of them for the summer.