I used Harddon's bloom/taste/THC booster mix that included (among other stuff) 1 tspn. of Jack Daniels Whiskey per 2.5 gallons of water, applied for three consecutive feedings. That small of an amount of booze didn't stunt anything.

I'm not really sure I like the possible reasons they list for why the plants are stunted, though:

"Miller isn't sure why the alcohol stunts plant growth but he has three theories that he is exploring.

-Growth is caused when plant cells absorb water and expand. The alcohol could be injuring the plant roots, preventing the roots from absorbing the water as efficiently.

-When alcohol is mixed with the water, the plant has to use more of its growing energy to extract the water from the solution.

-The plant uses its growing energy to rid itself of the alcohol it has absorbed."