True Living Organics - The Ultimate Guide to Growing All-Natural Marijuana Indoors (2012)

I make it a practice to sprinkle some blood meal on top of the soil mix, just before adding the bark
mulch. This gives both the plant and the microbial life a rich source of available nitrogen so they
won’t compete so much for it. Also, make sure your bark mulch is in its natural state, with no dyes or
paints added for esthetic value.
Composted and shredded bark mulch isn’t pretty, but it is very useful
Mulching TLO Growing Containers
I notice that many people growing organically indoors do not often use a mulch layer on top of their
soil mix. You always want to use a mulch layer when TLO growing. The mulch layer is all about
enhancing and increasing the microlife in the soil mix. This provides an environment that is shielded
from intense light, and from winds rapidly drying it out. These conditions are great for all the life in
the soil mix, including the roots of your plants. Always try to use composted and shredded bark mulch
for this purpose. If it is not composted, you will need to make sure there is some extra nitrogen up top
for all the life that will start decomposing (eating) the bark mulch. Actually, I would use some extra
nitrogen up there no matter what, because the mulch increases the populations of microlife, and if they
begin to run out of nitrogen, they will steal it from the roots, sometimes causing a premature nitrogen
deficiency which is indicated by the lower leaves yellowing, with this symptom progressing upwards
on the plant.