First time grower, was doing great until last week. Please help

[Xray1]

Hey everyone. Just wanna say thank you to everyone here for teaching me how to grow. I finally started my first grow recently with two mephisto cdlc x Skywalker seeds. Everything was going great until I switched to boom nutes and now my plant’s leaves are turning yellow with brown spots. I’m hoping y’all can help me turn things around and save them before it’s too late.

I grow in a closet in a small tent. Temp is between 76-81*f, humidity is 46-51%. My water is from the sink and around 7.9ph, 200ppm, 90ppm sodium, 18ppm calcium, 65 total hardness. I’m using a 240 watt led light currently at 80% which shows a lux of 40k at the top of the canopy when 18" away and I run it 20/4 hours. I’m using 3 part general hydroponics nutes(plus calmag and armorSI) using a custom feed chart I found on ICMag forum that I’ll attach to this post. I pH The water to 5.8 - 6 after adding nutrients. The plants were looking great feeding them 4 times a day with slight run off using the veg portion of the feed chart. Dark green leaves and no sign of burn but a week after they started flowering I switched to the Early Bloom Day 14 section of the feeding chart and summer hit and things got warmer and all hell broke loose. At the same time I switched to watering 6 times a day and ran out of water in the reservoir twice to the point that the pots didn’t weigh anything. The bigger plant also grew to within 9" of the light. So basically a lot of things changed at the same time and I’m not sure where to begin to fix this. I just raised the light to 18" after I took these pics. I think it was at 14" in the pictures. Now I need to figure out if the light is too bright at 40k lux or if I can go brighter. I also need to figure out the nutes as my guess is I’m burning them or have some type of lock out. Everything looked perfect on this plant using the veg portion of the chart so it’s hard to know whether changing to the bloom section caused my issues or running out of water a few times caused it. Or perhaps the ppm of the nutes plus my water is too high? What should I be shooting for in Coco with LEDs? I think I’ll go down to 5 times a day watering as well.
I’m willing to try anything y’all think to try to save my first grow.
Thanks!

[TestOfOath]

Your led isn’t burning them, it’s not quite strong enough even at 9 inches, maybe the slightest stress at best. Pretty sure it’s just plain heat stress and without modifying your closet or adding AC for cooling your options are relatively limited, look into adding a C02 bag to your grow just during flower, this makes the plants much more acceptable and even benefit from high heat during flower, people that use cmh and hps are the ones who usually do it cause of the massive heat from them but I think it would benefit you and fix your problems.

Your leaves show signs of potassium deficiencies to me but you need to process of elimination before you try addressing everything at once so you don’t exacerbate the current problems.

[TestOfOath]

Also, learn to read VPD charts such as these and try and keep your temp and RH in the green, at the very least not outside of the yellow.

Flower

Veg

[Xray1]

Cool. Thanks. I’ll check out those charts. Looks like I need 1.4 but I’m not sure what that means. I’ll need to do some research on what vpd is! If it’s a potassium deficiency it must be from lockout bc my current mix is supposed to have around 170ppm potassium. Would a manganese deficiency look anything like this? I’ll work on cooling the room down as well.
Thanks!

[NEK-Fowldog]

Flush those girls for week and then give em something like 6-4-4 feed at like a 1/4 of what you normally would. If they dont bounce back within 2 weeks, I’d say heat…

[KarmaFPS]

From what I could understand from your post your plants are in coco, you are using GH nutes & feeding 6 times a day, switched to a different fertilizer when it got warmer & now your plants are turning yellow.

Looks to me like a bit of nutrient burn, maybe shock & too much K too early in flower from that new nutrient line.

6 times a day seems excessive, maybe cut back to 3 or 4

Leaves turning yellow and dying during flower is normal, you have plenty of leaf on there.
trim off the worst ones & continue what you’ve been doing, the buds can still get huge even with 0 leaf.

[LabRat]

Looks like good old toxic salts buildup from long term overfeeding to me. I’ve had it myself fairly often even using medium levels of feed but with our low RH the plants pull up more nutes than they can use and it gets stored in the leaves until they start frying around the middle of flower.

Nothing to fix it but feeding quite low levels of nutes low on N and P can help slow the progress.

That is not normal yellowing but leaves literally cooking to death from the inside. It’s showing up near the tops as they have been working harder to keep cool and thus have more stored nutes. All things being equal it usually starts in the older fan leaves. Something like a P deficiency doesn’t start with the upper leaves.

[Syn]

@Xray1

going great until I switched to boom nutes

Veg nutes have high nitrogen, whereas flower nutes do not.

Until you start seeing mass necrosis, i wouldn’t worry. Toward the end of the plants life the plant will sometimes go completly yellow.

This was my plants 3 days before cut.

@xray1 your plants look good to me.
What is your ppm from your water?

[SeymourGreen]

I grow in coco, and on the coco for cannabis web site it says not to use tap that is over .3ec or 150ppm. May be this plus the added cal-mag is causing a lockout, or toxicity. Just my 2 cents.

[DougDawson]

That could be. When I switched to tap water I dropped the CalMag and added Epsom Salts. Calcium in tap water plus from Calmag can lock out Magnesium.

[GramTorino]

Also. Feeding at Ph if 6.2 can help with Mg uptake.

[Xray1]

Thanks for the friendly advice everyone. I made a few changes to start with. I dropped watering to 4 times a day instead of 6. And I did a flush with just water to try and get out the built up salts. I’m going to try and keep the room cooler and I’ll trim the bad leaves off tomorrow. Ppm with the bloom nutes plus my water is around 950 right now. You think I should try and water it down some to get ppm lower?

I think labrat is right about the toxic overfeeding as earlier I looked in the tent and found some hard white spots on some of the leaves. I looked under a microscope and that’s the only way to describe it. It’s not powdery or bugs. Makes me think it’s salts coming out of the leaves and drying there

[ShiskaberrySavior]

I’d water with a 6.2 ph and around 400 ppm flush till your run off match’s what your dumping in the top possibly 10/15 gals per pot if you’ve got 2000 ppm at the start of the flush .

[TestOfOath]

Could you elaborate more on HOW you’re watering? What system are you using to be able to feed 4 times a day? Hand watering that often would fuck a bunch of stuff up but it doesn’t sound like you’re hand watering

[space]

@Xray1

What should I be shooting for in Coco with LEDs?

I dont think you have a problem with the LEDs. But just in case,I advise you to download an app called PPFD Meter to your mobile and measure your PPFD.

Obviously this app doesn’t capture light as well as a professional light meter. So based on a post from Migro I use the following condition to ‘‘best approximate’’ the APP results with the actual measurements.

Between 0-600PPFD I multiply the APP result by 1.15
From 600PPFD I multiply by 1.25.
The migro used a real meter next to the app and from the graphs I took these numbers to approximate the values.

After you have your PPFD and DLI( the app calculates for you also) you’ll know if you have light problems or not. PPFD higher than 900/1000 is a sligtly indication.

[Xray1]

Thanks I’ll try that as soon as I can

[Xray1]

I downloaded the app but had a few issues. My phone reads higher than my lux meter by 10k so I’ll have to play with it and try to get the calibration the same. My phone reads 60k while the lux meter reads 50k. This caused the app to say ppfd of 1250 which I think would be closer to 1k. Which light should I be choosing on the ppfd section? There were a lot of options, none that seemed too close to my light.

[Xray1]

I have the Flora flex caps, bubbler, and pump

[GramTorino]

Coco feeding techno I found helpful. (I’m not using or selling their coco, but I do believe in less “fines” vs more)

Automation - Short & Frequent Watering - California Substrates | A New...

[TestOfOath]

I think this is where a lot of people were getting confused with your feeding schedule.

Most people don’t have something that sweet and are used to different numbers when they see people referring to watering and feeding.

Like the one dude said a general rule of thumb when you flush is to start nutes light, 1/4-1/2 strength just to rule out it being any excess, you should see a visible change in your plants one way or the other and then you can adjust from that point knowing you zeroed out and are starting from X.

If you Google “cannabis deficiency charts” (there’s probably a flower AND veg one) there’s a bunch of good pages from books I’m assuming that show exactly what plants look like progressively over each excess and deficiency, save as many as you feel the need to and refer to them any time you think something is going on.

Do this for yourself so you can learn over time, recognize the patterns of what a happy plant looks like and what a plant that’s starting to get sad in various ways looks like.

I think you’re doing just fine boss, it’s not something to completely freak out about your stuff still looks great, nothing is actually DYING off the plant yet she’s just mad a little bit which happens really really often in flower till you get your specific grow dialed in to it’s needs.

Like I said before I’d personally up the potassium on the ones that show the brown spots and yellowing starting at the outside of the leaves, but if I ever add potassium I also do phosphorus cause all it does it benefit flowers unless you manage to WAY overdo it some how

Side note: the way I learned to tell if my plants needed a watering or not was by lifting them at different stages of wetness cause the amount of water they hold is easily felt when lifting the pots