Leaves Curled On Edges

[tooldini]

I put my plants under my 400HPS and after a couple days I noticed a few of the top leaves were curled up on the edges. I had the light about 1 foot from top of plants. I figured since it was so cool up there it would be OK. Well from what I read the curling is from heat stress. I raised the light a little and tonight noticed some of the upper leaves are browning. Will this damage get better I have since raised the lights to just under 2 feet above plants?

[tooldini]

No just a cheapy HTG light.

[tooldini]

I was unsure of distance due to most of my growing has been under CFL's LOL you can almost lay them on the plant no problem

[pergamum362]

a picture says a thousand words..most likely they got heat stressed/burned ,the brown/crunchy spots will never heal...better to remove the damaged area.

[pergamum362]

probably since its not air cooled a good fan blowing right in between the light and tops will help if you havent already put one there.

[Medcnman]

Sounds like heat to me too. Although i have air cooled reflectors, i also have a clip fan on each of my hydro units to cool the air between the light and the ladies. $10 at big lots or meijers during fan season. Its hard to find ANY fan in a store right now tho. I would remove the dead leaves. But only the dead leaves. Thanks, Medcnman.

[tooldini]

thanks guys thats what I thought I do have a fan just not up there cause the temps were so low,, I guess I still need one though. I had been wondering about that thanks again

[Morhawk]

thanks guys thats what I thought I do have a fan just not up there cause the temps were so low,, I guess I still need one though. I had been wondering about that thanks again

 

You could also try raising the light, or training your plant to grow lower and wider. Perhaps a SCROG would be good. A fan shouldn't really lower the temperature that much in the room, as it is moving the ambient air around, but it will push the heat of the light away from the top. Plus your light should bring your room up a few degrees I would think, also.

[Timmahh]

the general thought is, if you stick the back of your hand under the light, if it gets too hot, its too hot for the plants. lift the light until your hand doesnt feel too warm.

[pergamum362]

Should be a fan in there anyway,air movement is very important.

[petoskeystoned]

I've personally found that having a oscillating fan at bulb level and somewhat close cools the immediate heat from the lights, but I also have fans in corners to keep the entire room at the same approx temperature. Rotate your plants if you can. Wind apparently helps with mites too. If holding your hand palm down at plant level for about one minute is too hot, its too hot. I find this to be true closer than about 16". I have recently added a 6" in line fan placed at the level of the bulbs (in the middle of it all) and redirected it to the house. this lowered the temp about 8 degrees Ave and warmed the house by 10 good luck!

[tooldini]

Hey Timmahh I did that when I set the light so it ended up being under 12" from top of plant but apparently that was too close So I will be adding my oscillating fan very soon. Thanks everyone for the help.

[CleanD]

Also there is such a thing as light stress... Moving from cfl's to an hid is big jump in lumens... I'd keep it up at 2' and move it down a bit every 2-3 days... In addition to fan... ;-) peace

[tooldini]

Thanks Clean your right, but I had them under a 198w Power Compact light. This light is awesome I put out so little heat so even though it was a higher wattage it still was probably much more stress under the 400 HPS.

[tooldini]

here is a picture. One day just green and curled and the next brown. Excuse the mess, still underconstruction but had to start flowering.

[newbie313]

Problem = heat

[tooldini]

Glad my first instinct was correct I hope it is better know that I have it around 2' above plants. The Deep Purple plant is still perfect and it was even closer to the heat so I am assuming it has better fight in it against heat. The White Widow is a DinaFem product maybe being femanized makes them weaker

[pergamum362]

yah, she got it bad, shell bounce back tho.looks like she was initially very healthy.remove those damaged leaves.

[The Digital Nomad]

It looks like plants did not protective cover for HPS if it was under CFL. It might have been cool in the room, but light produces HEAT ENERGY. Put your hand 1 foot under that light and you can feel it despite the ambient temperature. If the plant grew under CFL it should have been slowly introduced to the HPS - at least 3 feet away! so it can build a stronger leaf surface.

 

I would just back off the lamp and continue. Remember humidity is lower right now, so young tender plants need foilar spray to keep from drying out. You can have some green leaves that are just crisp they crumble in your fingers.

 

The rule of thumb for lumens and plant stage is :

 

Clones 800 to 2000 lumens Vegging plants 2000 to 8,000 lumens, and flowering plants 10,000 lumens for decent growth. You can exceed these lumens, but plants may not need more and it becomes electricity waste. Again calculating lumen loss - 80,000 lumen bulb at 1 foot, is 20,000 at 2 feet. I have seen plants grown under weak lights, you can still get potency, but its the yield that suffers.

 

DN

[tooldini]

DIgital thanks I figured they would be ok to go straight under the HPS because the power compact light was 198W but your probably right I should have kept the HPS much higher above plants. I will clip off the damage leaves, Now is there a proper way I should do that? Kinda like Topping a plant to get more main cola's Still learning here so I appreciate everyone help.

[The Digital Nomad]

DIgital thanks I figured they would be ok to go straight under the HPS because the power compact light was 198W but your probably right I should have kept the HPS much higher above plants. I will clip off the damage leaves, Now is there a proper way I should do that? Kinda like Topping a plant to get more main cola's Still learning here so I appreciate everyone help.

 

the basic rule of cutting or clipping a plant is 'no more than 20% at a time' - cutting away sun leaves basically slows growth as the plant has less energy. During veg I don't expect stress to effect it much, and those leaves are 50% damaged anyways. As long as you don't cut emerging sprouts, top it, or cut off branches - I don't think you will make it bushier.

 

It is not just about lumens, it is about light energy, the HPS just has more light energy in the form of heat than a CFL. Even if you grew under HPS, that plant is not ready to be exposed to direct sunlight - as sunlight has more heat energy and more powerful UV a/b waves that can burn the sensitive surface of the plant only used to CFL or HPS limited wave lengths.

 

So with any light change, I would do it gradually- CFL >HPS> Sunlight. Also, while I noticed that my Wonder Haze can grow inches to the aircooled lights, the buds that stayed about 12" away did better due to less heat stress.

 

DN

[pergamum362]

Just cut them off..I continusouly cut and prune my veg plants, only leaving about 12-18 inches of growth no mater how tall it gets...growth never slows down, infact after I prune all the weak spots where growth isnt getting light the plant grows faster since the energy is directed into good growth spots and theres a larger root mass for less growth.The dn is on to some things but you can take off way more than 20 percent and not have a negative effect...cut anything you dont want on it off at the stalk...pruning is one of the most overlooked aspects of a good crop coming together.

[pergamum362]

another thing, the wattage of a cfl compared to that of a hid is meaningless, HID of the same wattage will put out considerably more lumens than a cfl.The 400 you have probably puts out and initial lumen amount of 35 to 50k lumens depending on ballast and bulb combo, im sure that is substantially more than the 198 watt cfl.

[tooldini]

thanks,, I am gonna do some clipping tonight when lights come on. Got her raised up pretty good I cannot feel any heat on the back of my hand at plant height.

[tooldini]

I clip off most of the dead leaves and it still looks good. I had temps at 77 last night. They are growing good and I am pretty sure the Deep Purple is gonna be female. It was a Subcool seed that was a regular so unknown sex. Looking very female to me though.