Whats wrong with this grow room?

[stasis]

I recently stopped growing, sold my equipment and now my friend has started but needs help working out why the plants wont grow for him.

Put it this way, the seedlings are 3 weeks old and only just getting their third set of leaves coming through. Approx 1.5-2 inch tall. Strain auto ak47.

He is based in south yorkshire in the u.k. which is supposed to have the best water for growing ( supposedly )

This setup has cost a fortune so far £xxxx +

Light : 12/12 50w per ft ( 2x 800w , 16sq ft ) 15" away from tops

Water : Autoflower seedlings growing in 3 galon containers - watered every 4 or 5 days. The moisture meter reads between moist and wet. But i don't know whether the mter is working properly or not. PH @ 5.9 using canna coco nutrients. ( Started on 1/4 strength, with the recommended schedule )


Medium : Canna coco

Humidity : VERY LOW like less than 30% ( the gauge stops at 30 , so it could be 0 -30% ) however i have not heard of problems with very low humidity before ?

Temp : Between 75-78F day / 60-62F Night

CO2 Level : 400-500ppm day


Any ideas ??

 

[stasis]

There are no nutrient deficiencies visible.
+no signs of overwatering - however im not sure what this would be like ?

Possible problems :
Stock water EC too high ? - I seriously doubt it .
Water too soft ? Possible - south yorkshire water is very soft. However , this would surely show up as a nutriet deficiency , not just super slow growth.
Toxic water ? Chloramines/chrolide etc .... Unlikely , the hydroponic shops in this area we spoke with said they take their water straight out of a tap, and give it straight to their plants - with no problems !
Humidity? The humidity is very low. Off the scale infact. But i really don't think this would stunt growth ( the soil is plenty moist ! )
Too much light ?! Is that even possible ?

 

[WvMade]

you said there auto flowering? whats his light sced? i think you gotta go 24/0 or something

 

[tat2ue]

There are no nutrient deficiencies visible.
+no signs of overwatering - however im not sure what this would be like ?

Possible problems :
Stock water EC too high ? - I seriously doubt it .
Water too soft ? Possible - south yorkshire water is very soft. However , this would surely show up as a nutriet deficiency , not just super slow growth.
Toxic water ? Chloramines/chrolide etc .... Unlikely , the hydroponic shops in this area we spoke with said they take their water straight out of a tap, and give it straight to their plants - with no problems !
Humidity? The humidity is very low. Off the scale infact. But i really don't think this would stunt growth ( the soil is plenty moist ! )
Too much light ?! Is that even possible ?

If your water is super soft that may be the problem. Here in the States, to achieve super soft water you have to use large amounts of sodium(salt) in it. And high concentrations of salt is in noway good for plant growth and development...jmo

 

[bobbyhopefeild]

I recently stopped growing, sold my equipment and now my friend has started but needs help working out why the plants wont grow for him.

Put it this way, the seedlings are 3 weeks old and only just getting their third set of leaves coming through. Approx 1.5-2 inch tall. Strain auto ak47.

He is based in south yorkshire in the u.k. which is supposed to have the best water for growing ( supposedly )

This setup has cost a fortune so far £xxxx +

Light : 12/12 50w per ft ( 2x 800w , 16sq ft ) 15" away from tops

Water : Autoflower seedlings growing in 3 galon containers - watered every 4 or 5 days. The moisture meter reads between moist and wet. But i don't know whether the mter is working properly or not. PH @ 5.9 using canna coco nutrients. ( Started on 1/4 strength, with the recommended schedule )


Medium : Canna coco

Humidity : VERY LOW like less than 30% ( the gauge stops at 30 , so it could be 0 -30% ) however i have not heard of problems with very low humidity before ?

Temp : Between 75-78F day / 60-62F Night

CO2 Level : 400-500ppm day


Any ideas ??

By the sound of it you have a case of toxic salt build up which is quite common. This can be easily fixed by flushing the plants. You should also consider filtering your water or leaving it out overnight to release its withehld chlorine.

This could also be caused by nutrient toxicity seen as you have given the alnts nutrients at such early plants. #you shouldnt feed them nutr`s until at least 2 weeks into life.

Flushing will also help this problem as well as preventing any further build up.

Another reason might be your temp and humidity levels. Temps should be between 70 - 80 degrees and humidity should be between 50%-60%.

hope this helps

Hopefeild

 

[stasis]

Thanks for the replies guys.

Toxic salt buildup ? Not likely.
They have only just had their first watering of 25%nutrient ( before this it was plain water ! )

Light cycle ? 12/12 or 24/0 or just about anything can be used for autoflower, the more hours the better , but not neccesary. ( Think about outdoors )

I really wonder if its the water thats too soft.

 

[stasis]

Heres a water sample :

calcium 16.36ppm
magnesium 2.95ppm
chroline free 0.29ppm
chroline total 0.37ppm
aluminium ??µg Al/l
Fluoride 0.06ppm
iron 27.73ppm
manganese 3.30ppm
nitrate 4.54ppm
nitrite 0.0093ppm
sodium 10.58ppm
copper 0.0101ppm

Sodium maximum for marijuana 50ppm.
-Actual sodium = 10.58ppm. This is ok.

 

[shoemaker]

autos go for 20/4 or 18/6 they have a very short life cycle, mine showed sex in 12 days, at 8 inches tall, under a 600 watt mh at 20/4, if u give them 12/12 they are not gonna grow nearly as fast, it even says it on the site where i buy them to go to 20/4. hope this helps!

 

[stasis]

autos go for 20/4 or 18/6 ------- it even says it on the site where i buy them to go to 20/4. hope this helps!

Thanks i know mate .
But i really dont think this is the problem. Its something else.