Potting
soil with premixed plant food.
Everybody must have noticed those soil bags with beautiful pictures of healthy
plants on them. There is a sign in the corner :"with plant food". If you look
inside - you will see little green granules mixed into the soil. Use this soil
carefully! I managed to damage two of my plants with it.
It is possible that the mix itself is OK, I am sure the manufacturers use
complex calculations to verify the ratio of ingredients. But here is a pickle:
When you buy a 10L bag, you are not likely to use it all in one pot. It seems
that those plant food granules are a bit heavier then bits of soil, and somehow
they tend to move to the bottom of the bag. So when you open the bag and take
first handfull of mixture, it will have the minimal concentration of plant
food, while the last one will have mostly the plant food granules and just
little bit of soil.
Now, I didn't get to the bottom of my bag (otherwise I would realize all this
issue), but my Zebra plant, that I re-potted fourth from the top, got burned
very badly. I guess that part of soil already had an excessive concentration of
plant food. There is another problem that might arise, although I am not so
sure about that, didn't experiment with it: if the roots of the plant will come
to direct contact with some of the plant food granules - something tells me
that it can damage some plants too.
Once again, I am not saying that potting soil with added plant food is bad, but
if you use it, don't repeat my mistake. Mix the soil from bag well to make sure
that food granules deposited evenly through the mixture. Or limit it's usage to
just the top of your pot, making sure that root ball has regular soil without
plant food.
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