Potting mix and Perlite.

[davidwood]

I have an idea that maybe only Charlie can answer, but if others have any thoughts I would welcome them.

My problem is and always has been getting a suitable potting mix here in Vietnam, they do have coco coir but unlike Charlie’s mine is absolute rubbish.

The local product that is used a lot is burnt rice ash, this is ok for a while but it slowly gets very compact and crushes the roots, its just not suitable for Hibiscus, also I am not to sure about how clean it is and I have lost loads of cv’s to root rot and other fungi problems, it’s a real headache and upsetting to watch your cv’s slowly dieing.

What I can get hold of and know is good is Perlite, Worm Castings and Bat guano, I can also get easily a product called Bounce Back, it’s a 1-1-1 pellet fertilizer that’s added to the mix.

So my idea is and I want to know if it would be ok is do away altogether with coco coir and the rice ash and have the main ingredient of my potting mix as Perlite, I was thinking maybe as high as 70% [20% worm castings and 5% each of the other]. Charlie would this work? Do you think they would grow ok in this mix; of course I can alter the ratio’s I have mentioned if you think the need but I am at my wits end.

Not worried about the weight of the pot as they are all sunk in a larger pot, nor am I worried about the Perlite blowing away as I can cover with a mulch of Worm Castings.

[Charlie]

Honestly, David, this is a question only you can answer. What I mean is that this approach is far outside the norm and only trial and error will give you the answer.  It might work, but will depend on watering and fertilizing appropriately for whatever mix you come up with. Hibiscus are fairly forgiving but one thing they do not like is mixes that are too heavy and don't allow for enough oxygen in the growing media. That will not be a problem with a perlite based mix so it has a chance if you provide enough water and fertilizer.

Another thing to consider is that in a place where you cannot get modern horticultural products you may do better finding out what the locals use and going with that. Its probably too heavy but adding 25 percent perlite could work. You've probably already looked into this, but sometimes local solutions are best.

Or, you could start composting your own mix by setting up a compost pile to which you add lots of leaves, grass cuttings, and kitchen waste (careful not to add weeds with seeds). You have to do it right, turning the mix and checking the temperatures so that you get a true compost. When the compost is ready, add some perlite to it and you should have a great mix with lots of organic benefits for growing potted plants like hibiscus.

Let us know what happens as this is an interesting challenge.

Charlie

[davidwood]

Thanks Charlie, I am definitely going to give it a go and trial and error will be the key. I have researched a lot on the Internet where there is a lot of info, problem being the main promoters of Perlite is coming from people with a vested interest in Perlite, many say you can have success with a 100% Perlite mix, well I wont be doing that, also tons of stuff on Worm Castings but most do not recommend more that 20%, I will start with 10%.

I am confident I can make it work, my big fear is when I come to repot, I have visions of being left with a big ball of roots having watched the Perlite fall away, I need to find something I can put in the mix to bind it all together, I am not really confident enough to make my own compast and god only knows what creatures it would attract to my rooftop. Any ideas would be welcome.

[davidwood]

Chris I hope you can read this and give me your views, if you read above you will see why I am about to do what I plan, but as a recap all my cv’s are slowly dieing, I do not have 1 healthy plant in the garden. I have 21 cv’s coming and want to try another way to give them a chance.

I will make 20 gallon of potting mix.
80%   Perlite
10%   Worm Castings
05%   Bounce Back [organic slow release pellets 1-1-1 NPK.
0.5%  Bat Guano.
I will add 1 tablespoon of Epsom Salts for each gallon, I will then wash it all through with a liquid Seaweed Extract.

That is the base for the Potting mix. Up to now its all Organic, not really through choice but more its what I can get that I know is clean and good. I will add Iron and Fertilizers etc later as and when required.
I will also make a mulch 1/4inch thick of 50% Worm Castings and 50% Perlite to hold it all in place [I have already practiced with this mulch and it works quite well].

Chris 3 things, 1, can you see any major problems with it that I am not seeing, 2, the Bat Guano, is 5% to much as I have read its quite high in Phosphorous, and lastly if it does work well and I get a nice big root ball will I be able to re-pot [I am sort of thinking that that it wont bind together and I will end up with it all collapsing once out of the pot.

Chris I would love to hear your views, I have spent hours researching this and think it may have a chance, if it does it could put an end to all my problems but I am worried that there is something blindly obvious that I am not seeing [not unusual for me haha].

Interesting story getting the Bat guano, me and my mate traveled to this place in the jungle, we where meant to arrive at lunchtime but got lost and ended up there at 5pm, the fella was just going home but got out this rope ladder to climb down into the cave handed me a bucket and spade and said 1 dollar, he expected me to go down,I looked over into a black abyss and said no way haha,maybe he tries that trick with everyone, difficult to tell if he was smiling or not as he had no teeth, in the end after a short negotiation I gave him 2 dollars and he went down, I did hold the torch though.