Worms, spiders - good idea?

I was wondering if placing worms in the pot soil is a good idea to prevent overwatering and mold.

Also wondering if it was a good idea to deliberately place multiple spiders inside my greenhouse to kill all the annoying flies that can do considerable damage to my plants.

I figured doing this would be a lot better than polluting the plants with chemicals and things.

not sure about the worms
but the spiders would be good.
get some lady bugs too

not worms? I always thought they were good for soil. Ladybugs are hard to find.

Yes, I've never heard of it before, but worms would aerate the soil. That is a positive thing. You'll hear people write often that the soil is too compact and that oxygen/CO2 is getting to the roots and to add more sand or perlite. Worms would do this on their own...in theory...

i said i was unsure about worm..
canadian night crawlers would escape..
i think other worms might leave when food was gone ..
they might damage roots