Tops of plants bleaching.

[Buffoonman]

I'm using a 400W HPS extended spectrum lamp (Growlux) with an air cooled reflector. The temperature directly under the light is only 80 degrees but the tops of the colas directly under the lamp are bleaching it happened on my last crop also. I assumed its was the temp but 80 degrees dosn't seem excessive. Even though bleached the calyxes are still packed in trichomes. Its not a big problem as its only the top inch of the colas that are bleaching.
Any ideas on what it could be and how to solve the bleaching would be appreciated. The crop has about 10 days to go.

 

[Guest]

do you have a fan blowing over your tops...this happens when i dont...my cab never gets above 80......you mite want to raise your light a little...i use a 600 and i get about 6 inches from the bulb....i have tempered glass shield


if you notice the bud on the right... is a little higher than the rest...and has no fan blowing over it...its bleached

 

[TBug]

I'm using a 400W HPS extended spectrum lamp (Growlux) with an air cooled reflector. The temperature directly under the light is only 80 degrees but the tops of the colas directly under the lamp are bleaching it happened on my last crop also. I assumed its was the temp but 80 degrees dosn't seem excessive. Even though bleached the calyxes are still packed in trichomes. Its not a big problem as its only the top inch of the colas that are bleaching.
Any ideas on what it could be and how to solve the bleaching would be appreciated. The crop has about 10 days to go.

High buff! You in soil or hydro? Mine did that several times also, and i found that roots were rotting. I was using an ebb n flo set up. Got any pics? Im not sure if the rotting roots were directly related to the bleaching or not, could have been a combination of things. But as for my last crop, EVERYTHING else was perfect but te roots got too hot. Peace an GL, TBug

 

[Buffoonman]

Yes i have a fan blowing over them, and a tempered glass shield. You can touch the glass and it dosn't really feel that hot. The plants are about twelve inches from the light at the moment. Was thinking of getting a 600W lamp for the cooler weather to come but I am worried it will make the problem worse. I was wondering if a digital ballast would make any difference. There growing in Plagron Royalty mix soil.


Not sure if you can really see it in this picture.

 

[Guest]

my friend... raise your light...im sure this will solve your problem...i had a few plants get bleached on the top in late flowering... but i dont really care... i cant raise my light anymore.

 

[Buffoonman]

Thanks for the input guys.

 

[Growdoc]

sometimes it can be a serious mite infestation and sometimes root rot!

Growdoc

 

[mace_ecam]

looks like heat to me

You say 80F isn't hot enough?
Probably not, but i doubt that you can measure leaf surface temps, only ambient temp, ignoring the effects of radiant heat (ir)

Had the same under my 430W HPS with an aircooled hood.

 

[dogmeat]

Ive got a 400 running maybe 6 inches from the tips of the biggest plant in hydro and they are starting to bleach as well.

Not a cooled hood....about 90 degree's at root level.......cant seem to keep the room under 88ish...even with the flowering 1000W turned off.

 

[dre86]

The bleaching comes from the radiation the bulb puts out, not the heat...

 

[IAmTheHydro]

u can always chop the nasty bleached parts off and smoke em when they dry it only helps the lower buds grow more

mine always get too big i have to top and bend and tie and crack teh branches and cut a few bleached tops off

 

[420KushMaster]

goodlcuk

 

[Quiet_Riot]

Or maybe you have to fert em. Plagron says that one could begin ferting lightly after 6th week - total.

 

[Merman]

I highly recommend this product:

The Equalizer - Hot Spot Diffuser

"Simply slide this unique product over a mugul base socket on most horizontal burning reflectors to filter & disperse the intense "hot spot" of light directly under an HID lamp.
With the hot spot diffused, you can hang reflectors closer to the plant canopy while reducing the risk of burning the plants directly under the lamp.
The revolutionary shape, size and hole patterns were designed using the latest lighting development software.
The Equalizer will aid in improving the uniformity of your fixture by reducing the hot spot below the lamp."


My cab has very tight headroom (44 inches) and I can grow the buds three inches from the glass on my 400W without bleaching with the addition of this. I have an air cooled hood and very good aircirculation so I haven't had problems with heat.

Its basically an alumnum stick with pebbled reflector material.... its well engineered, basically reflecting the direct light from the bulb back into the reflector instead of straight down.