ok a old school grower told me to stick a nail throw bottom of main stem befor harvest a day befor and that would make plant shoot resin up ??? will that work or ruin plant??
This is probably from Mel Frank's and Ed Rosenthal's The Marijuana Grower's Guide (available on line here). The idea is that stressing the plant increases the potency. He also suggests sticking an iron nail in the stem as a remedy for iron deficiency.