Help - Stunted Purple Juice Auto?

[BoohdahLovah]

I’m on day 43 of an indoor soil grow of a Purple Juice autoflower from Herbie’s seeds. This is my second grow, and first for an auto.

The plant is only 8-10cm tall and looks like buds are starting to form.

I’d prefer to keep going through with the grow, so how can I maximise my yield? Or is it not worth it to finish it?

My grow journal is here.

Any and all help is welcome.

 

[JayGee]

I am no expert but if that is day 43, I would move on and start again. Do you know why it is stunted ? my first auto was stunted after I messed around to much with topping, LST and to many neuts, but still had a small harvest off it, but mine was 10 weeks till I harvested it, and it was only 6 inch tall. My second crop is 5 weeks in now and all plants are over a foot tall and pre flowering, and I just let then grow without messing to much.

 

[BoohdahLovah]

I am no expert but if that is day 43, I would move on and start again. Do you know why it is stunted ? my first auto was stunted after I messed around to much with topping, LST and to many neuts, but still had a small harvest off it, but mine was 10 weeks till I harvested it, and it was only 6 inch tall. My second crop is 5 weeks in now and all plants are over a foot tall and pre flowering, and I just let then grow without messing to much.

This is only my second grow and first for an auto, therefore I’m not very knowledgeable, so please bear with me.

I changed lights from a Mars Hydro Reflector 96 to their FC-3000 on day 33. So the light became more intense and the temperature went up maybe 10 degrees Celsius. It went from around 11-13 degrees to 23 degrees.

It’s currently winter here, and temperatures get to around 5 degrees Celsius at night. The tent is in a shed outside but the pot is raised off the ground. The lower temps didn’t affect the last grow’s height, the leaves just turned purple.

I was having an issue with the timer for the light before I changed it, where it would be on for 18 and off for 6, but after 7 days it wouldn’t turn on again. Due to being at work for most of the day period I didn’t notice and so I turned it on after almost halfway through the day period for that day. So lights go on at 6am and I didn’t notice until 5pm. This happened twice.

Other than that it’s been the same things done as the last grow, which was a photo period strain.

Please let me know if there’s any more info you need.

 

[BoohdahLovah]

Also, I haven’t done any training or topping at all.

 

[JayGee]

ok @BoohdahLovah firstly I am also on my second grow, but I am a horticulturist by trade, but just started growing the good stuff. firstly as I am in the uk, annd mid summer here we operate on centigrade not farhanheight, so when you say degrees is it 0C or 0F ? as for my seeds I start mine off in soil and they go straight into the tent, so when they pop, they dont stretch, the tent is same temp as my other plants so around 28oC
for the temp to drop from 23oc to 5oc is a big jump, it should only drop 10oc max, so by the time the soil warms back up, its time to drop again, so your plant is in a dormant stage (so it may be saved) your light issue, I cannot comment on as I am not sure myself. I have had to turn my lights off for an hour during the day, and this hasnt affected my plants, but for 12 hours, I cannot say. I suggest bringing it into the house for warmth and give it a boost. what feed are you giving it ?

these are my autos at 5 weeks old (35 days)

 

[Listersmeghead]

I’m on day 43 of an indoor soil grow of a Purple Juice autoflower from Herbie’s seeds. This is my second grow, and first for an auto.

The plant is only 8-10cm tall and looks like buds are starting to form.

I’d prefer to keep going through with the grow, so how can I maximise my yield? Or is it not worth it to finish it?

My grow journal is here.

Any and all help is welcome.

I would've thought the cold temps has caused the problem.
With autos being on a short veg schedule they need the best early start possible, a bit difficult out in a shed in winter though.

 

[Azimuth]

I’m on day 43 of an indoor soil grow of a Purple Juice autoflower from Herbie’s seeds. This is my second grow, and first for an auto.

The plant is only 8-10cm tall and looks like buds are starting to form.

I’d prefer to keep going through with the grow, so how can I maximise my yield? Or is it not worth it to finish it?

If it were me, I'd keep it going and treat it as a science experiment. With auto's the clock is ticking and there is not much allowance for repairing problems. One of the biggest challenges most new growers face is proper watering as our favorite plant plays by different rules. You can spend the time on research and practice to get it right or you can skip the learning curve altogether and come join us in #SIP Club.

So the light became more intense and the temperature went up maybe 10 degrees Celsius. It went from around 11-13 degrees to 23 degrees.

Cannabis is a plant that likes warmer weather. It  will grow in cooler temps but not very robustly as you've seen first hand. Ideally 23-30*C with about a 10* drop at night is ideal, but they can handle even higher temps than that. So, low temps are a big part of your issue.

The lower temps didn’t affect the last grow’s height, the leaves just turned purple.

Purple leaves could simply be a genetic trait although low temps will cause a deficiency in uptaking P, hence the purple colors on the leaves. Some growers deliberately lower temps in flower to get the pretty colors, but since it's a sign of a nutrient deficiency I could never see much point in deliberately causing that.

I was having an issue with the timer for the light before I changed it, where it would be on for 18 and off for 6, but after 7 days it wouldn’t turn on again. Due to being at work for most of the day period I didn’t notice and so I turned it on after almost halfway through the day period for that day. So lights go on at 6am and I didn’t notice until 5pm. This happened twice.

Auto periods are not affected by the light schedule so you shouldn't be worried about hermies. On the other hand, making sure your plant gets enough light (number of hours x intensity) is your main concern.

 

[Listersmeghead]

If it was me I would think about putting the light on for 24hrs continuous..that would stabilise the temp in your tent a little. Autos can handle it.

Are you extracting air from the top of the tent?
That was the traditional way when using burning hot grow lamps, led's are different.
Think about extracting from the bottom of the tent, so you pull the heat of the led's down onto your plants.
If you can stabilise your winter temps you'll get better results.

 

[Jack420]

I’ve ran it she was massive I seen doin autos in dwc gets the job done u probably didn’t do nothing wrong !!

 

[BoohdahLovah]

I would've thought the cold temps has caused the problem.
With autos being on a short veg schedule they need the best early start possible, a bit difficult out in a shed in winter though.

I’m starting to think that this might be the case. Thanks for your insight @Listersmeghead. My extraction is coming from the top so I might switch it and go from the bottom during winter. It’s worth a try at least.

 

[BoohdahLovah]

If it were me, I'd keep it going and treat it as a science experiment. With auto's the clock is ticking and there is not much allowance for repairing problems. One of the biggest challenges most new growers face is proper watering as our favorite plant plays by different rules. You can spend the time on research and practice to get it right or you can skip the learning curve altogether and come join us in #SIP Club.


Cannabis is a plant that likes warmer weather. It  will grow in cooler temps but not very robustly as you've seen first hand. Ideally 23-30*C with about a 10* drop at night is ideal, but they can handle even higher temps than that. So, low temps are a big part of your issue.


Purple leaves could simply be a genetic trait although low temps will cause a deficiency in uptaking P, hence the purple colors on the leaves. Some growers deliberately lower temps in flower to get the pretty colors, but since it's a sign of a nutrient deficiency I could never see much point in deliberately causing that.


Auto periods are not affected by the light schedule so you shouldn't be worried about hermies. On the other hand, making sure your plant gets enough light (number of hours x intensity) is your main concern.

Thanks for all of the pointers @Azimuth. I have only just come across SIP in the last few days. It’s something I’m going to look into. I’m guessing it is the low temps. I’m going to continue with this grow to at least get some further experience and hopefully get the best out of a not great situation.

 

[BoohdahLovah]

I’ve ran it she was massive I seen doin autos in dwc gets the job done u probably didn’t do nothing wrong !!

Thanks @Jack420. I saw your diary of the Purple Juice auto and was looking forward to having a go at it. I guess it’s all part of learning.

DWC is on my list of things to try in the future, but maybe not until I graduate from the beginner class.

 

[BoohdahLovah]

Thanks everyone again for your insights. I’m going to continue with this little stumpy girl and see what happens.

 

[SmokingWings]

The plant is only 8-10cm tall and looks like buds are starting to form.

Judging by the looks of the 2nd photo it just started to form buds several days ago.

I’d prefer to keep going through with the grow, so how can I maximise my yield? Or is it not worth it to finish it?

Like @Azimuth mentions, treat it like it is a science experiment. Feed it as normal and do nothing special to maximize the yield. Just watch it grow, watch the buds form and watch out for the usual nutrient deficiencies to show up. If something does show up try to figure out why it is happening, what to do about it, and maybe even attempt to fix the issue. But, trying to max out the harvest will not accomplish much other than an exercise in futility.

While all that is happening you can start some new seeds for a second grow. It becomes a good way to apply some of what you see happening to the other plant as a way to improve and maximize the harvest with the new plant.