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Is this a magnesium deficiency ?

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Indoor/Outdoor: Indoor

Growing Medium:  canna terra professional Soilless mix

Growing Style: Topping / SuperCropping?? ( Bent branches until they would crack causing them to lay on their sides and form a knuckle )
Watering/Feeding Frequency: when pot is about 50% of it's wet weight
Nutrient Strength (PPM/EC): canna terra flores, Seasol, rhyzotonic, cannazym and molasses -  EC = 2100 atm using canna nutes schedule..

PH Levels: 5.8-6.0
Temperature/Humidity Levels: Night 18deg C, Day 26 deg C
Air Flow/Fans etc. fan for circulation and a fan for venting both  24/7
Lighting Type (CFL/HPS/MH etc.): HPS / LED
Total Wattage: HPS - 400W / LED - 300W
Growth Stage: FLOWER - DAY 15 ( from first sign of flower)
Plants Age: 4 months ( I stuffed up in veg so I let it grow until it was big enough to turn )
Cannabis Strain: Bag Seeds




***Update I just added this to give the basic trace elements I wasn't sure about which deficiency it has so this should cover them all and then some.. I hope. ****



This is my first grow and I can't wait to smoke some of my own home grown bud..  :yahoo:, Im wondering if this is a magnesium def? And does epsom salt cure this?  I have noticed that the ends of most of my leaves are burnt.. I have been careful not to give high levels of the nutes but it seems to still have some burning on the tips of the leaves.. I have also stressed the hell out of these plants when they were in veg by staving them of fresh air so I don't expect to get great results just to learn so my seed bank seeds don't suffer the same fate.. :)


So I have been following the canna schedule for nutes and feeding and use the  " feed - feed - water "  I always ph the TAP water to 5.8-6.0 and just got a EC pen so I could add molasses with out going above the recommended levels.. about 2 weeks ago I started to add Organic unsulphured molasses at a rate of around 3 tablespoons per 8-9L.

I didn't notice any issues so I kept feeding the with every water and one feed. 


Any advice for my setup or nutes or what ever please let me know.. :)

PS what are the thoughts on canna terra professional soil.. It seems to be good but not what you should get for the $$ Im thinking about going to a hydro either bubble or flood and drain in buckets. Any one going to try convince me otherwise? I added 10%-15% extra perlite to the soil I put an amnesia auto in.. it's still doesn't drain fast enough but much better..








Edited by The Jackel
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I have no experience growing with canna terra, though I have plenty of soil experience. I think you have a little bit of nute burn on the tips of some leaves, I don't feed as strong as canna suggests as I feel they don't need it. I also think you have ph issues causing nute lockout. I would change to canna coco with about 1 quarter perlite. Use canna coco nutrient with ec around 1.6, ph 5.8 as you have been doing, plenty of air movement from an exhaust fan and an oscillating fan and your yeild will increase. Hope this helps

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Digital cam colour capture, and computer monitor differences make it hard to be sure with pictures, but I'd have to say what I'm seeing looks like a combo of natural die off of lower shade leaves and a bit of nute burn.  Plant doesn't look to be in a perfect state of health, but also doesn't look to be in trouble.


I agree with Hermananian about not running full strenth nutes, I try to gauge what the plants need and adjust the strength of the mix using an EC pen based on that, and find that I never end up near manufacturer specs.  I generally run an EC between 1300-1800


Canna Terra, and other soil mixes, seem to be popular in the States, but can't say I've seen many members here using them.  I wouldn't go so far as to tell you to ditch it for coco, but I would encourage you to amend it with coarse perlite at around 30%.  Don't hold me to this, and double check, but if it's a soil mix, shouldn't you be running a higher PH?  5.8-6.0 is in the hydroponic PH range, and I thought soil PH was 6.5ish, though Terra is a specially manufactured product so may be different.


Maybe a good flush and a feed at a lower EC and letting the pots dry out a bit more between waterings might perk things up a bit.  Best of luck

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That is an obvious mid stage Mg Deficiency, as they are in flower though i wouldnt correct the deficiency by foliar spraying Magnesium sulphur though (epsom salts). When you are mixing your nutrient solution add some at about a teaspoon a gallon. Wait 4 or 5 days for improvement, if little improvement water them with a MgS Solution again.


Nothing to be too concerned about, the yellowing of the bottom fan leaves is common at this point in your grow.



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What's a tablespoon? 15 ml or so?   45ml/9L might be a bit too much.  I have used molasses @ 15ml/4L and it may be combining in effect concurrently with a low ph (I would aim for 6.3-6.7 like SPH mentioned) and maybe see how she goes with a weaker nutrient dilute?  I am only new to the soil thing but yeah, sounds like a little heavy on the molasses , ph and nutes.  Just fine tuning man.  You're gonna love it when you smoke/vape/eat your own meds :D

Hope this made some sense and all good things for the rest of your grow.

Faith :sun:

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The most common deficiency in cannabis is probably Mg, with N a close second.... ya'll should know this.

Hi Puff, I agree with the deficiency part, though with such a high ec feeding schedule it shouldn't be happening, also the die back is way too early, those buds are very young, and again the feeding schedule shouldn't allow it.

Edited by hermananian
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Hi Puff, I agree with the deficiency part, though with such a high ec feeding schedule it shouldn't be happening, also the die back is way too early, those buds are very young, and again the feeding schedule shouldn't allow it. Makes me wonder if its been in the same pot for 4 months !


Must be my monitor as I can't really see it, but I won't argue about whether it is there or not.  But I agree that the stage of flowering and feeding schedule should be well and truly covering it. 


As was once explained to me with deficiencies in hydro, it's most likely a problem with the rootzone, or PH is wrong, can't see why that would be much different in a specialised soil mix being fed with specialised nutes.  Hence my suggestion to look into what the correct PH is, and give the medium a good flush.

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Oh sorry, i meant the most common deficiencies of cannabis are Mg and N. It could be that when lights were flipped to 12/12 there was far from adequate N uptake causing the lower leaves to yellow faster than expected.With canna terra the soils ph shouldnt be at 5.8 to 6 all the time, with canna terra nutes you feed once or twice a week allowing the ph to fluctuate from 5.8-6 and above. I think he meant that his nutrient solution is 5.8 to 6, though in soil it should not remain at this ph level. The water feeds should allow the ph of the soil to increase before the next feed of canna terra nutrients. Say the nutrient solution he feeds the plants are 5.8 to 6, then the water he gives them should allow the ph to increase until the next feeding of nutrients. In soil the ph shouldnt remain at 5.8 to 6 there should always be ph drift - its not hydroponic cultivation. Cannabis prefers an alkaline medium when grown in soil with the ph of the soil medium being above 6.4 for maximum magnesium availability to 6.8, the ph drift in soil ensures a greater spectrum of availabity of the micronutrients/macro nutrients cannabis requires.
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