HELP! Plants dying due to light/nute change

heys at RUI this is only my 1st indoor and I'm trying to figure out what's wrong with my girls
they were vegging strong but after switching from the 400W MH bulb at 18/6 to the HPS bulb at 12/12 they began to show problems.
the new, yellowing budsites were the first obvious sign of a problem, and then shortly after the larger, older fan leaves showed yellow discoloration and necrotic spots.

I thought sulfur deficiency, so i flushed with water and then with an epsom salt mixture and they only got worse.
I also began feeding them bloom nutes as i changed their lights
Now 4 have died and the others have been reverted to veg.

what can i do to prevent this?

make sure u have a good amount of foliage b4 going into flower and would start them on atleast flowering additives if not flowering base nutrients right on the 12/12 switch.we really do need photos man.also remember your will get yellowing leaves in flower its not 2 bad aslong as u have a few healthy leaves left.

girls require a higher nutrient level when going into flowering as well. what did you change in respect to what you feed them when you switched to 12/12? i know you said bloom nutes, but is it high enough? what ppm do you run in veg/flower? just a bit more info and i can make an educated guess =p

what do you mean reverted to veg?a light cycle change back to a vegging light cycle is the only thing i know of that can cause a plant to revert to veg.
Whats your ph at? what kind of medium are you using? how often and how much and what kind of bloom nute are you using? how far into flower are you? how long ago did the problem start?

=ian= said:

girls require a higher nutrient level when going into flowering as well. what did you change in respect to what you feed them when you switched to 12/12? i know you said bloom nutes, but is it high enough? what ppm do you run in veg/flower? just a bit more info and i can make an educated guess =p

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i am feeding the Botanicare Commercial growing system 17 grow and bloom, but i also added in ( hindsight, maybe shouldnt have) some snow storm and floralicious. I stopped feeding the grow nutes but assumed there would be enough available nitrogen remaining in the soil as the plants were verdant during veg and i never encountered and toxicity or deficiency issues.

Maybe there wasn't enough nitrogen or an overdose of P?

as for the ppm i dont have a soil tester only for water but i never fed them too much although i was using full stength

smallclosetgrowr said:

make sure u have a good amount of foliage b4 going into flower and would start them on atleast flowering additives if not flowering base nutrients right on the 12/12 switch.we really do need photos man.also remember your will get yellowing leaves in flower its not 2 bad aslong as u have a few healthy leaves left.

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there were some healthy leaved but 5 plants have died and the others seem to be okay i

i will try and get up some photos for you guys asap i know it will help the diagnosis

MrGhettoGrower said:

Before I pass judgement on your issues I like to see a picEvery plant is like me you joe blow we all have at least 1 turn at death

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very true my friend a sick plant is one think but dying babies is just too much haha

darkdestruction420 said:

what do you mean reverted to veg?a light cycle change back to a vegging light cycle is the only thing i know of that can cause a plant to revert to veg.
Whats your ph at? what kind of medium are you using? how often and how much and what kind of bloom nute are you using? how far into flower are you? how long ago did the problem start?

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yes i reverted to veg by switching back nutrients and light

my pH is unknown as i also only have a water tester but i have been using 24 hour sitting tap water and checking the pH of the water before feeding, trying to keep it at about 6.4
i had only given the girls one round of bloom nute before encountering this problem and now they are on veg again.
this problem showed about a week and a half into flowering

To test it just go and run some water through it like normal next time when you water and test the ph of the runoff.

heres my 2 cents, we need pics. but a stab in the dark you said you use snow storm, an feed at full strength. THATS BAD, snow storm causes a massive uptake of nutes an will cause burn. some strains can take it some cant. Cut your solution down to half an see how that goes.

Palmdiggidy said:

heres my 2 cents, we need pics. but a stab in the dark you said you use snow storm, an feed at full strength. THATS BAD, snow storm causes a massive uptake of nutes an will cause burn. some strains can take it some cant. Cut your solution down to half an see how that goes.

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you think it was the snow storm?
i know this is probably for more mature flowering plants but what does it do exactly?

i will try and test my runoff water as well

actually i give my clones snowstorm but at a verry small dose like 1/3, and all through the plants life it seems to help with roots. the dude at my hydro shop said hes killed them with snowstorm so any thing is possible. let us knw how its goin. have a growtastic day

i am currently revegging..
and it is taking FOREVER to see new growth