pre-sexing

I am doing a large outdoor grow with high mids sativa bag seed . i was wondering if anyone has any ideas about pre sexing by placing a piece of black plastic around a node for a few days. can this cause a plant to stress out and go hermie

dont think it would go herm on ya but wont make it flower either

why wouldnt it make em flower. i've read lots about doing that method. they sense long darkness. they flower there.

the light would still hit other leaves wouldn't it?

Preflowers, as opposed to full blown flowers, generally appear after the fourth week of vegetative growth from seed. Check carefully above the fourth node. Please note that preflowers are very small and and almost impossible to differentiate without magnification. A photographer's 10x loupe is handy indeed when examining preflowers.

As the images below demonstrate, the female preflower is pear shaped and produces a pair of pistils. Frequently, the female preflowers do not show pistils until well after the preflowers have emerged. Thus, don't yank a plant because it has no pistils. Pistillate preflowers are located at the node between the stipule and emerging branch.

Also, some female preflowers never produce pistils. A female preflower without pistils is difficult to distinguish from a male preflower. Thus, hermaphodite issues should not be resolved by the appearance of preflowers, without pistils, on a plant otherwise believed to be a female.

Female (pistillate)



Image courtesy of MrIto

Female (pistillate)


Image courtesy of Uncle Ben

The male preflower may be described as a "ball on a stick." However, its most recognizable feature is its absence of pistils. Sometimes, a male plant will develop mature staminate flowers after prolonged periods of vegetative growth. These appear in clusters around the nodes.

The following image shows a male plant in early flowering. Staminate flowers are located at the node between the stipule and emerging branch.

Male (staminate)
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Image courtesy of PLAYn

Image courtesy of PsycoXul

dude. are you sure you are not thinkin of indoor. cuz i grew weed last year out door. the cops got to it. but i had it for like 2 and a half to three months. i looked every time i visited my crop. i never saw a preflower.

yea my dads theory on them was that when they cross its fem and when they don't they're males.

Mines a little over 8 weeks, already showing female pre-flowers, a calyx and 2 pistillates at every node here and there. I got a question, do the pistillates naturally turn from whitish to orange-ish/brownish? I'm still in Veg, 24/0.

THIS IS AN OUTDOOR FORUM. NOT INDOOR. i am speaking of outdoor plants, which take more than 3 months like indoor. this is about presexing. read first post.

when outdoor plants sex out depends on where you live but if you basicly live in the northern hemisphere they will start mid to late august if you plant in the spring , i live in indiana and light outside wont be 12/12 till sept. 26 but plants will show sex mid to late august when it is 13/11 because of such a long veg (if planted in spring) peace.