I pulled this off of Attitude...
Dinafem Seeds White Widow is the most potent cannabis on Earth and is named for the abundance of trichomes, giving the plant a whitish tint. It is also one of the more powerful strains of marijuana (alongside AK-47 and Afghan Kush) with a very high 20%-25% THC content.
White Widow feminized seeds are (60%/40%) indica/sativa cross-strain and is best suited to indoor cannabis cultivation.
Cannabis seeds grow as high as 35-80 cm with the yield up to 450 gr per m2. It's suggested to flower (12 hour light) this marijuana variety for 8 weeks, but 10 weeks will really give you the crystals you are after.
Try to turn the lights off altogether the final 2 weeks of the flowering cycle- or at least down to 8 hours. This keeps the flowers from re-growth and stresses the plant into giving up its last drop of goodness as crystal to protect the flower! The buds have so much THC on them that it is hard to see them at all.
White Widow feminized seeds produce plants that give you the taste of freshness laced with many fruits, because of the strength of the cannabis crystals - the only real taste goes hand in hand with the expectorant effects of the THC. The smell is strong pungency. It first hits you, then follows a sour sweetness with the final whiff ... turning sweet. If a plant could have a strong body odour then the White Widow needs a deodorant.
Cannabis smokers adore its sweet, thick, acrid smoke that imparts a hammering stone. Extremely powerful. Recommended for experienced smokers only.
Dinafem's site says 60 hours of darkness....