Light burn?

[Fantomlimb]

Plants grow taller because there isnt enough light and so they shoot up to get above the canopy of plants blocking their light. Theres no canopy of competing plants so I assume theres not enough light.

I dont know about you but I use like 1000 watts of light when growing...300 watts seems very low to me for plants that size.

Also, I would personally LST instead of topping

300 true watts is more than enough for a 3x3x5 tent. My stretch may have come from the 105 watt light I used during veg but I doubt it. A 400 watt LED is enough for 10 square feet of grow. Let’s put it this way, my first grow, which was my last one, started in an AeroGarden with a 30w LED light about 1”-2” above the canopy. I switched that plant to the 105 watt LED at beginning of flower and then to the 300 watt LED about 2 weeks in. That’s what produced the buds in my last pic and my 1.5 square foot canopy by 11” tall plant produced 3 oz and a quarter. To me it doesn’t look like this plant is stretched due to lighting as it isn’t spindly and weak though internode spacing is much longer than my last plant, I chocked that up to strain. I top because that’s what I know best. I like having multiple colas over one main stem, plus this plant was monster cropped so already was splitting into multiple main stems. I did tie down the branches for a bit but it got to be too much of a hassle to change the water out.

 

[NuttyProfessor]

I’ve never heard that phrase but I’ll take it!

Its all good !!

 

[Fantomlimb]

It sounds like you have things well in hand. You are going to need to do an experiment. It is my belief that because of the size of your plant, feeding at the rate you have been is not quite enough, hence the beginnings of a deficiency. Try upping your feed by 25% and see if this causes better color and a halt in the progression of the problem you are seeing. I think everything else you are doing is within normal ranges and should not be a problem. The alternate experiment is to assume that it IS a burn, and feed 25% less, hoping it will go away. It is my belief that this path will make the present problem worse.
It is your choice... you are the gardener in charge! Good luck!

So today during top off my PH was 4.9. Way out of range. So from yesterday till today it went from 6.0 to 4.9. According to my chart; falling water, PH and EC says I should flush Rez and up EC on refill. Sounds like exactly what you say to do. So I flushed, and refilled with a 1.7 EC. From here I’ll keep on eye on her. The problem seems to be spreading to lower leaves so will see how this res change helps if at all.

 

[NuttyProfessor]

@Emilya

 

[Fantomlimb]

Hey guys last question, while super cropping, i broke the skin of a stem. It’s not major, just a small slit along the bend. Should I duct tape it or just leave it?

 

[Emilya Green]

Hey guys last question, while super cropping, i broke the skin of a stem. It’s not major, just a small slit along the bend. Should I duct tape it or just leave it?

it is probably already sealed and on its way to total recovery. These plants are pretty tough.

 

[Fantomlimb]

Ok so not last question lol. So today, testing EC and it’s .9. Dropped from 1.7 to .9 in 24 hours. Water level did not drop as much as it usually does. Should I change Rez again? That seems like an insane amount of nutrient uptake. Weird thing is that the water level barely dropped at all.

 

[Fantomlimb]

Ok so not last question lol. So today, testing EC and it’s .9. Dropped from 1.7 to .9 in 24 hours. Water level did not drop as much as it usually does. Should I change Rez again? That seems like an insane amount of nutrient uptake. Weird thing is that the water level barely dropped at all.

According to my chart the plant is eating but not drinking. It calls for a slightly lower EC or complete res change. What do you all think?

 

[Emilya Green]

Here is where you need a hydro person to advise you... at least now you know the plant was indeed quite hungry... I would just keep going with that in mind, but I am an organic soil grower, so I really don't understand your method.

 

[aphrodisia]

I posted this at the end of my nutrient burn thread but considering this is a different plant and different problem, I thought I’d start a new one. I started flower 2 weeks ago. When in veg, the plant was under a 105 true watt Vivosun light and a 30 true watt full spectrum bulb. When I switched to my flower tent, it went under a Mars Hydro 305 true watt TSW 2000. The plant is unfortunately really tall and I can’t figure a way to rig my light up higher as the air filter is in the way. I’ve already looped the 12” light hangs to get them to 6” hangs and the ratchet hangers cannot be shortened anymore either. However the Mars Hydro has a dimmer switch on it. Currently it is about 17” above the canopy and 80% power. So my questions are, does this look like light burn, and is there anything I can do short of taking the whole thing out of the tent? Should I lower the power? I only worry about not enough light getting to the lower parts of the plant, but then again I’ve removed a lot of that so there isn’t much down there anyways.

Nice looking plants, if the tops are begining to yellow then its most probably light burn, this problem always shows up just as you begin flowering with people using LED's, if as you say raising the lights isnt an option as you have no more head room then try giving them some calmag. When growing with LED lights calmag is an essential thing to have to hand I found this out the hard way hope this helps.

 

[NuttyProfessor]

If this isn't already solved lol ,ive had some zkittles so its made me think about this again but dont want to read again lol
Make sure if your water is hard your using the right nutes for hard water ,
if you use a lot of ph down phosphoric acid it gives a (P) toxicity and that will show up as a zinc, then iron ,then mag ,in that order good night

 

[Fantomlimb]

Here is where you need a hydro person to advise you... at least now you know the plant was indeed quite hungry... I would just keep going with that in mind, but I am an organic soil grower, so I really don't understand your method.

Thank you for your help!

 

[Fantomlimb]

Nice looking plants, if the tops are begining to yellow then its most probably light burn, this problem always shows up just as you begin flowering with people using LED's, if as you say raising the lights isnt an option as you have no more head room then try giving them some calmag. When growing with LED lights calmag is an essential thing to have to hand I found this out the hard way hope this helps.

Thanks for the tip! I already use Calimagic with my nute soups. My soup is the Flora Trio, Calimagic and Hydroguard in tap water. I lowered the amount of calmag by half when I switched to flower. Would you suggest upping it? By how much if so?

 

[Fantomlimb]

If this isn't already solved lol ,ive had some zkittles so its made me think about this again but dont want to read again lol
Make sure if your water is hard your using the right nutes for hard water ,
if you use a lot of ph down phosphoric acid it gives a (P) toxicity and that will show up as a zinc, then iron ,then mag ,in that order good night

My water is moderately hard. Not soft, but not really hard either. It ranks at about 188 PPM TDS with a 116 on the hardness scale. I don’t use too much PH down as my water comes in at 7.3. Usually 1 ml if that of PH down to get it in range in about 1 gallon. I used Zero Water filtered water during some of its veg state but it became too much of a hassle to filter 8 gallons every week for both plants so I switched back to tap water.

 

[aphrodisia]

Thanks for the tip! I already use Calimagic with my nute soups. My soup is the Flora Trio, Calimagic and Hydroguard in tap water. I lowered the amount of calmag by half when I switched to flower. Would you suggest upping it? By how much if so?

I would up it to the full amount and see if that helps, but I dont grow hydro I grow in soil so dont know what the full amount is for you.

 

[Fantomlimb]

I would up it to the full amount and see if that helps, but I dont grow hydro I grow in soil so dont know what the full amount is for you.

Full amount is 1 tsp per gallon. Checked today and she drank a lot. Like a lot a lot. She was at that line yesterday.

 

[Fantomlimb]

So testing water today and PH stayed the same and EC stayed the same. Unless I’m not doing it right. Do I measure EC before or after I refill with water. If before the EC stayed the same. If it’s after then the EC dropped. Anyone know the proper way?

 

[Fantomlimb]

So Id like to update and thank everyone. Here she is today. Top recovered its green appearance. The yellowing seems to have stopped though the leaves that yellowed don’t seem to be turning back to green. At least I know it’s not light burn and your suggestions helped fix it. Thank you all!

 

[Anny Tang]

Hemp plants show signs of light burning, including upturned leaves and what's called "bleaching." Bleaching is the white or yellow discoloration of the leaves closest to the light. Mild burns can also be recognized when the veins of a plant turn green and the rest of the leaves turn yellow.

I posted this at the end of my nutrient burn thread but considering this is a different plant and different problem, I thought I’d start a new one. I started flower 2 weeks ago. When in veg, the plant was under a 105 true watt Vivosun light and a 30 true watt full spectrum bulb. When I switched to my flower tent, it went under a Mars Hydro 305 true watt TSW 2000. The plant is unfortunately really tall and I can’t figure a way to rig my light up higher as the air filter is in the way. I’ve already looped the 12” light hangs to get them to 6” hangs and the ratchet hangers cannot be shortened anymore either. However the Mars Hydro has a dimmer switch on it. Currently it is about 17” above the canopy and 80% power. So my questions are, does this look like light burn, and is there anything I can do short of taking the whole thing out of the tent? Should I lower the power? I only worry about not enough light getting to the lower parts of the plant, but then again I’ve removed a lot of that so there isn’t much down there anyways.