Purple Haze height

During early to mid veg stage plants do not need as much light. However during late veg you want to crank up the light. The amount of recommended light is expressed in DLI (daily light integral).
This is a handy chart for reference. I took it from an article in greenhouse production news (GPNmag)

A DLI of 45 translates roughly into an average PPFD of around 700 during an 18 hour period. The decline in DLI numbers from 45 to 25 is when light hours decrease to 12 hours.
If you like numbers this is the formula
PPFD X 3600 X hrs of light per 24 hrs (eg 18 or 12) divided by 1,000,000 = DLI
700 X 3600 X 18 hrs/ 1,000,000 = 700 X .0648 = 45
700 X 3600 X 12 hrs / 1,000,000 = 700 X .0432 = 30
Spider farmer gives you PPFD maps at various heights and footprints.


When I turned up the light from 200 to to 220 I got the lighter tips on the short plant. I thought it was being light stunted so I went back to 200 watts. I’m 18 inches from the tallest top now, closer to 24 inches higher for the short plant. When the short plant was getting light tips it seemed the growth was stalled compared to the other plants so I turned it back down.

Should I just start going up now starting 4th week and not worry about what the short plant looks like with it or let it go another week and then turn it up?

Also, can anyone say from the tips whether I should feed again today half strength or water and feed a couple days down the road? I thought I might see what water does in terms of the droop and claw I got last time when I used molasses.

Is this a static reference to cannabis in general?
Don’t different strains require more/less light?
Am I supposed to reach max light even with this strain? Most I get from the wall is 430

about the feeding if anyone has any opinion on it, I need to get something in them today, either water or feed. I guess I couldn’t do harm with just water today.

Are the tips indicating note burn? As you can see they’re in the netting now so they can’t be moved out, and they’re just sitting in saucers that hold maybe a gallon at best so flushing would be a major pain if it has to be done before further feeding.

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Your tip burn is very slight and the clawing negligible. Feed how u please. No alarm. Actually u can feed again today. If ur super worried about the tips, lower the strength of your solution.

Generally most numbers in reefer is a general. Ive had Wedding Cakes with burned tips at 800 ppms and Sherbert’s that were yellowing from the same feed because they wanted more.

Some plants can absorb lower pH’s some need it spot on at 6.6…


thanks Purp. Heading over to feed today. I think I’ll stick with the half strength, ~ 1000ppm or so.

If I had a ton of “backup” I’d be more adventurous in how I treat the plants. Once I get this one out of the way I think I’ll be better for it and can make some adjustments in the next grow.

As long as I still have these nutes left I think I need to find a way to make flushing easier in terms of how I settle the plants and maybe coming up with something that allows for flushing in place in a simpler way.

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Your doing one of the most important things. Paying attention and reading your plants. Often times it is interpretation but it comes with experience. You can also have differences between individual plants of the same strain. The four haze I have in the tent are good examples. Why are two of them 6 - 8" taller than the other two. Same same across the board.

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Don’t go over this number in veg and flower won’t be much higher than that (1,100 to 1,200 ppm)

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And once again after watering/feeding we get major claw and droop. Is this the beginning of lockout? Could this be leftover from the molasses issue? Is this a sign I have to flush?

Today was half strength or so, 1010 ppm. This didn’t start until I did the molasses and only in flower.

I’ll also note that since doing the molasses I’ve got red stem going on with every plant. Wasn’t this bad before the molasses.

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Gonna hafta explain this one. Only thing I see on the SF website is a map with SFT on it. I have an app that I originally used for initial LUX measurements if that can be used for this.

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And after the claw, comes this:

Another few hours and they’re pointing almost straight up. NOW what?

Didn’t turn anything up, still at 200 watts from the wall. This is almost comical they way these plants are reacting to basically nothing.

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I don’t see anything to get worked up over. Plants often respond as you’ve seen after watering and suspect some may have a root issue. (Not saying yours does) and light pointing up usually indicates plant is shedding light instead of absorbing it. Whether intensity or temperature; only you would know.

I wouldn’t go over that amount unless plant shows signs of a def.

A runoff TDS would be nice but would suggest doing at normal watering interval. Just PH’d water, 20% or so runoff, take the last 1/4 cup or so and test for salt concentration. If it’s over 1,500 ppm or so you can just continue water only until that runoff number falls down to your feeding range. Some plants are highly sensitive to changes and some, not so much.


Half strength is too much. That claw is Nitrogen abundance. Just water for a bit. Next feed try a quarter.

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Sorry @Myfriendis410 said it much better. Ignore me lol.

The praying hands means the water is hitting the spot and they are loving the light

Ok, something else I didn’t know. All I knew was too much light causes extreme praying. Corn does the same thing but from too much light. That’s what I thought was happening here all of the sudden.

I think a consensus here is keep at or below 1000ppm, which I think I’m gonna do since I haven’t flushed.

Tomorrow should be a water day. I’ll clean the tray and pull an extra 20% water through and see what the runoff is. I’ll post back later.

Today the plants again look good with slight praying after 8 hours light. I’ve never seen a vegetable or flower show such extreme reactions to feeding and light. This must have something to do with pushing these girls to the max, I guess I should expect extreme responses to minimal changes.

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Alrighty then. pH’d RO water through the little guy until decent runoff produced a ppm of 1060. I’ll post back what happened with the droop after an hour or so.


runoff is 1060. Looks solid to me. Did you catch ph of runoff?

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Actually no. That was another mistake. I use the same meter for TDS as for pH. Don’t know why my head was up my arse on that one.

When I water or feed it’s pH’d to around 6.2. I usually water/feed till there’s a tad bit of runoff, each plant gets a half gallon. Next time I water I’ll get the pH too.

You think the pH may be high with 1060 ppms in the runoff? Is that a lot of buildup that could increase the pH?

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My experience is build up will lower ph. If you have been feeding around 1000 I would not be concerned . PPM look good.
When told I should water / feed enough to produce 15-20% runoff I thought it to be waste - time & nutrients. But in the end it makes sense. Consistently washing through that much helps maintain the mediums pH & ppms. It is a good practice to apply.

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