1st frost Sept 18th, marijuana hasn't flowered - advice?

[Healthie]

Hi everyone,

I have 4 Marijuana plants (Harlequin CBD) growing in an approximately 8x8 space in the ground. They have not flowered yet and are approximately 4.5-5 feet tall. The first frost is scheduled for Sept 18th. my concern is the freeze killing the plants and not getting any yield. None of the big box stores have greenhouses in stock. I have a canopy and was thinking of putting that overtop of them and taking leftover 3mm poly plastic to act as walls, and then weighing the 3mm poly down with stones or logs. I would keep one flap loose to get in/out of this makeshift "greenhouse" My questions:

1. Given the situation is this my best option to preserve the plants and hope they flower before the frost kills them?

2. Is there anything I can give them to push into flowering stage? I know they need a 12/12 light/darkness ratio - we're currently at 6:25 am sunrise, 7:55 PM sunset - approximately 13.5 hrs light/ 10.5 hours dark. I don't have access to something that will shrowd them in complete darkness; save throwing tarps over the canopy.

Thank you!

[bacchi]

1) Yes. That's pretty standard (well, tarps and pvc hoops). If it gets really cold, you can run an extension cord out there and use a 100 watt incandescent in a work light cage.
2) No idea.

[Healthie]

Thanks for advice - it’s gunna look rough ;)

Here are some pics. They are very bushy. Should I prune them a bit? How long for these to produce anything?

[Healthie]

A few more:

[BikeFanatic]

Those look great, are you sure they are female?

[Paper Chaser]

None of the big box stores have greenhouses in stock.

Harbor Freight? They sell a 6'x8' and a 12'x10'.

[Healthie]

Pretty sure - it’s my 1st grow but I don’t see balls on the branches.

The harbour freight ones would be great but I don’t trust how long it would take to get up here.

[Healthie]

For those interested, this is what I’ve decided to try:

I cut & taped vapour barrier over a 10x10 canopy and used logs to weigh the tarp down. I’m going to keep it closed at night and open one side during the day to allow for airflow. I was told it needs 10 more weeks to flower in late July; so should be roughly another 6 weeks. I did a bunch of pruning yesterday. Fingers crossed it yields something!

[frugalnacho]

They don't need 12/12 to flower, although that's usually the schedule that is set indoors.  In reality the plants start making a hormone to flower during darkness, and the hormone is disrupted/destroyed in light, so once the nights get sufficiently long the hormone will be able to reach critical concentration and begin the flowering phase.  That usually starts happening around 14/10, but 12/12 makes it happen faster and so is really convenient to replicate indoors.   The fall equinox happens around Sept 21-22 most years, so unless you live close to the equator you want your outdoor girls well into flowering before they ever hit 12/12. 

Flowering is a gradual phase that happens over 7-14 weeks, depending on strain and environmental conditions.  I am a little late to the party (thread started 3.5 weeks ago), but those pictures you posted are in the vegetative state and have not even begun flowering.  You cannot identify sex until flowering begins.

I would estimate those plants to be a minimum of 8-10 weeks from harvest at the time you took the picture.  No matter where on earth you live they should be significantly into their flowering phase by early September when you started the thread.  Are they under a big a street light? Or a bright garage light, or some kind of light source that might be interfering with their night cycle?  I hate to be the breaker of bad news, but those definitely look like they won't finish before winter sets in.

1) Yes. That's pretty standard (well, tarps and pvc hoops). If it gets really cold, you can run an extension cord out there and use a 100 watt incandescent in a work light cage.
2) No idea.

Using light as a heat source (during night) is a bad idea! They need total darkness to keep their hormone levels during the night time.  Light interrupting their dark cycle will stress them, and if you have sufficient light can actually reverse their flowering and revert them back into the vegetative state, although these don't look like they ever left the vegetative state. 

[fixie]

They both appear pretty healthy.  One appears to be a little chlorotic.  Note the contrast in the leaf veins.
It could be that the cultivar is more sativa dominant and thus adapted more to equatorial regions.
Look into the leaf axels for tiny white hairs emerging from tear drop shaped calyxes.  If you see them, you have a female plant.
Response to day length varies a lot in cannabis, but flowering will not occur until the plant is physiologically mature.  If this is from seed, they may not reach maturity before fall.
-fixie

[Healthie]

Hi everyone,

Thanks for the replies  Frugal & Fixie - They are healthy and have been flowering - they're week 7 into it now. buds are small, but the cola's are pretty good. I don't have a jewellers loupe and may not end up buying one. I'm going to let them go for at least a few more weeks - we've finally begun getting frost but the plastic has protected the plants so far. It's definitely dicey and I wouldn't recommend the covering I've used; as water has weighed it down and damaged the plants a bit; but it looks like we're still rockin.

Frugal -

there is a street light maybe 75 feet away.
For the little weird lookin' one - any idea of what I could have done to make it healthier? They were all supposedly the same breed.

I'm anticipating harvest will be some time in November. I started these from seed in mid-april or mid-may; which would put the cycle at roughly 7-8 months.

[frugalnacho]

Starting time should be irrelevant to harvest time, so long as it was started before the flowering phase.  The flowering is almost 100% photo dependant, and unrelated to the age or size of the plants.  Vegetative growth will continue and the plant will get larger and larger as long as it gets sufficient light (and the dark period is short enough to not trigger flowering).  Once the night is long enough to allow the hormones to build up to critical levels the flowering phase will begin.  This can be used to grow a plant any size you want.  You could start a plant indoors and allow it to grow for over a year with lots of light until it is huge, then flower it or place it outside.  You could also start flowering plants when they are only 6 inches tall. 

You posted those pictures 6 weeks ago on Sept 5.  I don't know when the photos were taken, but those plants were definitely still in the vegetative stage, so they can't be any further along than 6 weeks if the pictures were taken immediately before posting, and they started showing signs of flowering immediately afterwards.  It seems strange to me to see those plants were still in the vegetative stage when you posted though.  At that same time all other outdoor plants I saw this year were well into flowering.   I am around latitude 42 (Detroit, Michigan).  Depending on the specific strain, harvest time around my latitude is around right now.

If you started them from seed then you have a good chance of having a mix males and females.  You need to identify any males and destroy them ASAP before they pollinate anything.  In the future I would recommend ordering feminized seeds from supplier to ensure you have only females. 

A street light 75 feet away shouldn't have any effect on the flowering phase. 

I would think a bigger concern than frost would be consistently cool nights, which means you'll get dew and have consistently wet plants.  Cool temps and wet plants could equal mold.  I don't have any advice to combat this, other than just be aware of it.