planting medium for emersed culture of Sri Lankans...

[lampeye]

I've searched around a bit, but I'm not quite getting the info I'm looking for.

I'm interested in growing a number of the more common Sri Lankan crypts (specifically, parva, walkeri, wendtii, becketii) emersed, and I'm curious what would be an ideal substrate. Would peat + sand be TOO acidic? And what are your thoughts on drainage holes for pots versus no drainage holes (these would mainly serve for root aeration, yes?)?

[illumbomb]

Just to share my experience with C. wenditii, I am growing them in a plastic flower bed (no holes) and the potting media I am using is nothing special, just what I bought from the local supermart. I flood the flower bed with water slightly just above the soil level and the cryptocorynes have been flowering continuously for the past months.


my flower bed with no drainage holes (to retain water)


the type of potting media at the base of the bed, just a thin layer (this is rather acidic, I tested it at about pH of 4.5 when mixed with water)


the type of potting media used at the top of the bed, a thicker layer (I have not tested the pH level for this, will do so and let you know)


the flowering cryptocoryne wendtii


double flowers

Don't ask me why I mixed different type of potting media, I just did not have sufficient of 1 type of potting media to fill the plastic bed then.

[hwchoy]

I assume you have some fish in the water?

[illumbomb]

Errrr no, but I know your concerns. The above photographs are taken during a rare "high tide", the water level is usually fluctuating between a few mm above soil level (just visible) to under the soil level (meaning I will top up water when this happen).

I have added BTI (granular form) in the planter box as I have discovered mosquito larvae previously (so guys, be careful if you ever want to try such method), but the BTI don't seem to have any adverse effects on the plants.