This will be the last photo of this experiment.
VFTs grown in a mix of peat and pine needles appears to grow better than in the common mix of perlite and peat. Best growth occured in a 50:50 mix. However the experiment was only conducted on single plants for each medium type. A larger group of plants grown in each medium would need to be tested to statistically verify this finding.
Pine needles certainly do not harm the VFTs and can safely be used as a substitute for perlite. If indeed the pine needles are resulting in better growth of the plants then possible reasons for this are given below.
1) It is possible that the needles maintain the acidity of the peat creating a longer lasting, more stable acidic environment around the roots. Unfortunately I did not have any means o testing the pH to confirm this.
2) The pine needles might be slowly decomposing releasing small amounts of nutrients into the peat, sufficient to benefit growth but too low to harm the plant.
3) The filamentous nature of the needles may create better aeration of the peat. It was noticed that the pine needles medium did not compact as much as the perlite medium and remained more more spongy to the touch.
Edited by mantrid, 10 September 2012 - 11:44 AM.