Forcing an outdoor photoperiod to flower

[Glenganja]

I’ve grown a few autoflowers in my greenhouse so far with varying degrees of success and failure. With those seeds I got a freebie photoperiod Bruce banner which I planted up in a container. I live quite far north and won’t get 12/12 light/dark until October but being in the far north will almost certainly get heavy frosts during the flowering period (12 weeks?)and even with my limited knowledge know that’s a bad thing!

I have a small shed which is very dark but not totally light secure, there are a few very small slithers of light which may get in - as in through slight gaps between wooden slats here and there.

Is this light secure enough to force it to flower?

How much more might it grow?

Growing autoflowers means I have no experience of topping, so I haven’t topped it. If I do so now, will it inhibit the height of the plant (already about 1metre tall, the shed’s about 1.5metres high) or just bugger it up?

I was hoping to be able to harvest before November hence forcing it now - hopefully.

All and any advice will be gratefully received.

[crucialbunny]

I've seen and read that there are many growers who believe absolute dark is key to kicking into flower. That being said, I have always grown outdoors with streetlights, houselights, full moons, and light pollution of every kind and my plants have always flipped. How important it is in forcing a plant I can't really say but it sounds like you don't have any other alternatives.

[F10werChyld]

Those light leaks you describe will definitely fuck with your girl. Once switched to 12/12 she could double in height, so be prepared! I'd probably try bending her over and training her to be low. It'll be difficult at this stage but you can pull it off.

[JDU]

Yes you can top her anytime before flipping.
& tie the branches down low. You'll get more tops & make room for at least a ft. (1/3 m) more height.
You can staple cardboard or anything else that'll block the light over all the gaps.
You'll be ok- go with yer gut.

[Glenganja]

Thanks for the feedback.

i reckon I’ll top her today and hang off a week or so to force her - that should give me time to lightproof the shed. It was a free seed so anything I get from her is a bonus.