Hi everyone!

After thoroughly going through Al's advice on house plants and container mixtures, I've determined that almost all of my plants are dying because of my overwatering them (and Kelso, one of my kittens, taking a leak in my ficus elastica pot), and having them sit in garden soil instead of even a poor potting mixture (which is quite common where I live, in Bangalore). The perched water under all my pots was revelatory, and made me a believer in a respectable potting mix.

So I did a bit of my own research on what plants need from soil, what makes good soil good (in the immediate context, it's 30% air-filled porosity or AFP, as also confirmed in Al's posts), how to crudely measure AFP, and what I could use as substitutes for the 5:1:1 and gritty mix. Almost everything seemed to conform to Al's advice, but it was never thoroughly explained why, which makes customisation a little hard to do, especially since most of the constituents (like perlite, coco husk chips since pine bark fines are nowhere to be found here) for the mixes are prohibitively expensive here in India. It's just coco peat and wholesale expanded clay aggregate that's affordable here.

Does anyone here know what would happen if I simply dropped one or more of the coco husk chips, granite grit, perlite from these mixes?

I should probably tell you what I'm working with now:

• I live in Bangalore (average temp is about 25 deg Celsius, but inter-day varies from 10-35 deg Celsius, 11-13 hour days, relative humidity of 50-75%, and with moderate to heavy rain 3-4 months yearly)
• I have pots both indoors (moderately lit), and on my west-facing balcony (that gets quite hot and sunny by 5pm in March-May, and gets drenched during the rains)
• I'll be gone on a six-month work trip during which a neighbour with zero plant experience will be (over) watering them once every 1-2 days (and my plants should be able to survive this time!)
• Also, since I'll be buying constituents in bulk to make a total of about 150 litres of potting mix, keeping things simple like having a single mixture for all my plants helps me keep cost and effort reasonably low

I have about 2-3 weeks to repot all my plants before I''m gone, and was hoping one of you kind souls here could help me :)

Cheers and thanks a lot,

Josh