I am a newbie gardener, and would like to plant around 15 polyalthia longifolia trees in my garden.
The main problem here is that my garden's reddish-clay-soil seems to be compacted.
- Clay sticks under my sandals.
- No worms in the compacted soil.
- Rainwater doesnt drain easily, and on some spots he rainwater doesnt drain eventhough i have digged a hole at 50cm depth, and when i digged deeper i found out that the house-developer had buried their building debris around 50cm under the surface. Digging further than to pass through the debris and the water can then drain normally. The device i used to dig is this.
My main concerns are that:
- The trees will have their growth stunted because they cannot break through the compacted clay soil, especially there's building debris underneath.
- Combined with bad drainage, the root can also rot.
- Also compaction doesnt provide a lot of pores that are good for root growth.
So i did some online searching on how to make the soil porous, enabling good water drainage, mixing compacted clay soil with organic matters to create a good environment for the trees and i came to this conclusion:
- That i should dig the soil,
- Remixing the soil with rich top soil, small-sized pumice stones, rice husks + rice husk biochars, composts
- And water the soil with EM4.
What i am unsure is that how deep should i dig and remixing the soils ? Should i go to 1 meter depth ? Because the tree can grow very tall, so i assume the root would go deep also.
From my further reading online articles, some advised to avoid digging to deep because the soil will sink deeper with time, causing the tree's root collar to be lower than the soil surface, and in the end will help fungus grow and make the trees sick. Maybe i just need to raise the soil height on the plantation spots to address this issue ?
Another concern: As per my experience with polybags containing the mixture above, the soil becomes porous indeed with good water drainage, but it seems that the plants do not have stable soil to attach to, and i had to repositioned the plants from time to time to prevent them falling sideways.
Or maybe all of these are just too much for tree planting and that i should just skip soil amendment ?