Over the last year I’ve noticed that some of my plants seem to grow really well for around eight months and then bam…just like that, they expire and go to plant heaven within a day. What’s strange is that right up until the moment of their departure they look quite healthy (no infections or infestations). However, lurking beneath the soil is often a clump of mushy roots.
After trying several brands of potting mix and various watering regimes (all to no avail) I decided to investigate making my own potting mix for container plants. My search led me to an excellent resource from Laguna Hills Nursery in California. The owner has a YouTube channel here and in this video he explains why your soil may actually be killing your plants.
I’ve been experimenting with adding some sharp sand and perlite to a peat moss-based potting mix that I bought a while ago that doesn’t contain any compost. Once I’ve potted my plant in this, I add a thin layer of a soil mix that I bought to the surface of the potting mix. It contains horse manure and top soil (along with perlite, sharp sand and peat moss). I’ve planted some fruit trees in this and so far they seem to be doing okay.