My seedlings are yellowing once again. Why am I cursed with this?

[Wastei]

Well it's what everyone says about AN, so I followed that advice for autos. It's a hydro nutrient like, it does work in substrate, but apparently you gotta go a bit lower with that stuff, especially with autos.



I went though biobizz, canna, and now AN, and they all show up with the same symptoms. That's the weird thing.

Soil mix has been biobizz, canna, normal garden potting mix, and now empty peat moss. All showing the same symptoms.

That's why I'm going a bit crazy, I don't know what the suspect is when I go through 3 different nutrient lines and several substrates, yet still end up with the exact same problem - yellow new growth in the seedling stage.

I did succeed in my last grow, and I literally did the same things I always do, and for whatever reason it worked out. I wish I knew what's wrong, that's why I'm asking you guys, you know best

1. Improve watering frequency and technique. Your growing in soilless and should aim to feed as often as possible to keep pH and EC in range.

2. To big pot for the size of plant. You're either suffocating roots or killing them off by letting the pot go to dry in patches.

3. Keep following recommendations from users regarding nutrient strength instead of manufacturers recommendations, one is there to help from experience and the other want to take your money.

4. Your soil mix is probably already amended. Adding plant food on top of this for the first 6 weeks will cause problems in a already amended soil.

Hope that helps!
Cheers!

 

[Acid]

Yep, we're back with the same old problem, luckily only with one seedling so far. I'm on day 7 after the seeds popped open, all of them autoflowers.

I'm still confused as to what exactly the problem here is. Each and every plant has the same substrate, same water. No nutrients, just PHed to 6.5.

I used 7gal final pots directly, as most auto users usually do. 5gal BioBizz Allmix on the bottom of each pot, as it's hot substrate. Then 2 gallons of 50/50 All Mix and Plagron Pro Mix on top, to have a layer of soft nutrients for the beginning.

I watered each pot with 5L of water (25L pots, 5L water each), PHed to 6.5 - I then let the substrate activate over 2 days, as recommended by Biobizz, at a good 25°C. While that happens, I germinated the seeds, and planted them 2 days later in the now perfectly moist substrate.

Humidity 70%, temperature 75°F, 24/7. PPFD set at 300. They will pop out the soil a day later, and everything looks wonderful. Dark rich green color. Around 2 days later, each seedling will get 200ml of tapwater, PH 6.5, in a circle around the plant. And now, I already have one seedling that's back to turning a screaming bright yellow at the new growth, with yellow veins and blotches all over it. Once again. It's always this. It's not tips of the first leaves slowly turning yellow, it's not brown spots, it's none of that. It's ALWAYS the new growth turning bright yellow, and then death.

I'm glad that 3 of the 4 still look fine so far. One has a tiny bit of nutrient burn on the tips of the newest growth, I imagine it touched the rich substrate on the bottom already, but it stopped burning & seems to be fine already.

 

[Bill284]

Yep, we're back with the same old problem, luckily only with one seedling so far. I'm on day 7 after the seeds popped open, all of them autoflowers.

I'm still confused as to what exactly the problem here is. Each and every plant has the same substrate, same water. No nutrients, just PHed to 6.5.

I used 7gal final pots directly, as most auto users usually do. 5gal BioBizz Allmix on the bottom of each pot, as it's hot substrate. Then 2 gallons of 50/50 All Mix and Plagron Pro Mix on top, to have a layer of soft nutrients for the beginning.

I watered each pot with 5L of water (25L pots, 5L water each), PHed to 6.5 - I then let the substrate activate over 2 days, as recommended by Biobizz, at a good 25°C. While that happens, I germinated the seeds, and planted them 2 days later in the now perfectly moist substrate.

Humidity 70%, temperature 75°F, 24/7. PPFD set at 300. They will pop out the soil a day later, and everything looks wonderful. Dark rich green color. Around 2 days later, each seedling will get 200ml of tapwater, PH 6.5, in a circle around the plant. And now, I already have one seedling that's back to turning a screaming bright yellow at the new growth, with yellow veins and blotches all over it. Once again. It's always this. It's not tips of the first leaves slowly turning yellow, it's not brown spots, it's none of that. It's ALWAYS the new growth turning bright yellow, and then death.

I'm glad that 3 of the 4 still look fine so far. One has a tiny bit of nutrient burn on the tips of the newest growth, I imagine it touched the rich substrate on the bottom already, but it stopped burning & seems to be fine already.

Soil could be a touch hot.
Get a little coco or spent Soil and put it around the seed.
Fresh little roots won't get burned that way.
Giving her time to grow before hitting hot nutrients.


Stay safe
Bill284

 

[Acid]

Soil could be a touch hot.
Get a little coco or spent Soil and put it around the seed.
Fresh little roots won't get burned that way.
Giving her time to grow before hitting hot nutrients.


Stay safe
Bill284

Yeah, that's why I mentioned "Then 2 gallons of 50/50 All Mix and Plagron Pro Mix on top, to have a layer of soft nutrients for the beginning."

The top 2 gallons of substrate around each seedling are pretty much a light mix for autos, and the bottom 5 gallons are allmix

 

[Bill284]

Yeah, that's why I mentioned "Then 2 gallons of 50/50 All Mix and Plagron Pro Mix on top, to have a layer of soft nutrients for the beginning."

The top 2 gallons of substrate around each seedling are pretty much a light mix for autos, and the bottom 5 gallons are allmix

That's the standard method but it happened anyway.
So something without nutrients right where a solo would sit might be in order .
A little coco or used soil.



Stay safe
Bill284

 

[Acid]

That's the standard method but it happened anyway.
So something without nutrients right where a solo would sit might be in order .
A little coco or used soil.



Stay safe
Bill284

The seeds themselves are in coco jiffy plugs, if that's what you mean? I germinated them in coco plugs, and then removed the skin / net of those plugs afterwards so the roots have no obstacle to go through

 

[Bill284]

The seeds themselves are in coco jiffy plugs, if that's what you mean? I germinated them in coco plugs, and then removed the skin / net of those plugs afterwards so the roots have no obstacle to go through

Give them a couple days see what they do.
After everything you have done they should be fine. Perfect actually!
A few more leaves will tell us for sure.


Stay safe
Bill284

 

[Sunasun]

Looks like it has dry pockets. This is why you should always moisten all of your soil. She's probably using her reserves to regrow a dead root system. Essentially treat her like a clone for a few days. Dome her if possible to allow her to draw moisture from air to regrow roots.

 

[Acid]

Looks like it has dry pockets. This is why you should always moisten all of your soil. She's probably using her reserves to regrow a dead root system. Essentially treat her like a clone for a few days. Dome her if possible to allow her to draw moisture from air to regrow roots.

This is one of the topics that I still need some more info about. I've never seen damage like mine because of dry pockets, this problem seems to be so insanely rare, yet I've even had it happen in coco with daily waterings from seed onwards. How exactly to you avoid dry spots with autoflowers, if you can't water the whole pot every time in the early stages, as that would just rot the roots over time?

 

[Roy Growin]

This is one of the topics that I still need some more info about. I've never seen damage like mine because of dry pockets, this problem seems to be so insanely rare, yet I've even had it happen in coco with daily waterings from seed onwards. How exactly to you avoid dry spots with autoflowers, if you can't water the whole pot every time in the early stages, as that would just rot the roots over time?

Roots will not rot in coco so water away as you please, it must be kept moist
Start with small pots so you can flood it but it still dries 24-48h
A kelp tea early on preconditions coco, works as a surfactant and growth stimulant

This NL seedling was given CaMg, 1/4 strength feed and kelp in the first couple of days above ground

NL-seedling.jpg

• Roy Growin
• Feb 4, 2024

pH should be around 5.6-6.2 depending on your nutes

 

[Sunasun]

This is one of the topics that I still need some more info about. I've never seen damage like mine because of dry pockets, this problem seems to be so insanely rare, yet I've even had it happen in coco with daily waterings from seed onwards. How exactly to you avoid dry spots with autoflowers, if you can't water the whole pot every time in the early stages, as that would just rot the roots over time?

I'm also unconventional and up pot my autoflowers every 2 weeks. 4 inch starter, then 1 gallon, then 3 gallon. I tried starting an auto in its final pot but that was a spectacular failure.
Was a bagseed, but I think the failure was on my end not pre wetting my soil properly.
Good luck acid

With failure comes knowledge.

- some dead guy probably

 

[Roy Growin]

I'm also unconventional and up pot my autoflowers every 2 weeks. 4 inch starter, then 1 gallon, then 3 gallon. I tried starting an auto in its final pot but that was a spectacular failure.
Was a bagseed, but I think the failure was on my end not pre wetting my soil properly.
Good luck acid

With failure comes knowledge.

- some dead guy probably

Yep - photo plants you can afford the stunted growth above ground whilst the roots explore, then the top explodes
Do that with autos and you'll get a small plant that matures before it has a decent rootball
Coco plug > 1L > 5L [maybe 10] is perfect for an auto in a tent grow and makes water/feed easy
Works for me

 

[bluter]

you would find it easier starting in a solo then up potting. getting the feed water cycle correct for a seedling in a large pot is tricky.

The top 2 gallons of substrate around each seedling are pretty much a light mix for autos, and the bottom 5 gallons are allmix

i'm not entirely certain on the media, or how you should be feeding at the moment.

the media doesn't look too hot, which is a common issue for autos, although autos generally start a touch better in something completely neutral. photos usually fare better on cold/ hot layer mixes.

most layer mixes are water only for at least seedling to early veg and can be problematic when handing off to nutes.

 

[Roy Growin]

They promote that method with 'Just add water'

 

[bluter]

They promote that method with 'Just add water'

they do, but most cold/hot layer mixes don't have enough to get all the way through flower. unless you are using large buckets, and if you are you can still run the risk of burning the plants as it is not organic and the nutes can release with bad timing.

edit : i don't think that is what is happening at the moment.

 

[Acid]

As far as I know, it's "organic". I don't know to which degree, but Biobizz is all about organic, even though I wouldn't count this as true organic grow. Soil really needs to be warm, otherwise it won't work as good, I experienced that myself too.

Now my question - Leaf temperature and VPD. Do you guys rely on this? I use a LED barlight, and my leaves feel cold to the touch, while the tent itself is at a cozy 78°F right now, with 65% humidity. I never really thought about the leaf temperature at all, until now, just to understand more about all of this. The box itself is really warm and wonderful, but the leaves feel like they're maybe at 65°F or something like that, way colder than the tents environment.

Is this something to keep in mind? I do actually have a laser thermometer, but not at home right now. I'm highly interested in what my leaf temperature is, but is it really something to worry about? I know it's pretty much useless for HPS and similar lamps, but I heard that LEDs do in fact have problems with actually putting heat off

 

[bluter]

As far as I know, it's "organic". I don't know to which degree, but Biobizz is all about organic, even though I wouldn't count this as true organic grow.

it's an organic source nute line. it's not an organic or living soil grow. true organics are water only with no nutes added.

Soil really needs to be warm, otherwise it won't work as good, I experienced that myself too.

i wasn't referring to temperature lol
we were discussing the way you've layered the media in the grow pots.

Now my question - Leaf temperature and VPD. Do you guys rely on this?

you can. it's not needed and i would solve for the issues at hand before taking on more complicated stuff. vpd won't mean a thing if you can't get past seedling.

I use a LED barlight, and my leaves feel cold to the touch, while the tent itself is at a cozy 78°F right now, with 65% humidity.

your environment is fine. temps could come up a touch to 84f and the humidity would be better a bit lower closer to 55-60%. 65% is getting into bud rot territory if it holds that high in flower.

overall those aren't bad conditions. i've grown under similar.

I never really thought about the leaf temperature at all, until now, just to understand more about all of this. The box itself is really warm and wonderful, but the leaves feel like they're maybe at 65°F or something like that, way colder than the tents environment.

the leaves of the plant will self regulate to a degree. that is what are noticing.

Is this something to keep in mind? I do actually have a laser thermometer, but not at home right now. I'm highly interested in what my leaf temperature is, but is it really something to worry about?

work through what you have going on now first.

I know it's pretty much useless for HPS and similar lamps, but I heard that LEDs do in fact have problems with actually putting heat off

vpd works the same for all lighting systems. led simply produces less heat doing it. that's a good thing.

 

[Acid]

Okay, next update: 3 out of 4 plants survived, one is 100% stunted and pretty much a failure, with the same yellowing as always. The other 3 look fine so far.

I'm already germinating a new seed in a solo cup, just trying it differently this time with one transplant, going against the "bro science". It'll probably poke out tonight.

With this, I will change to a 4gal pot, instead of the 7gal pot I already have filled, so I dumped the substrate out of the 7gal onto a big plastic sheet and, coming with it, I.. killed the old seedling. It's day 10 now, and it looked like day 3 or 4 at most, and that'll just make everything worse with an autoflower. Trust me, I did go through with it once, and ended up with 1/2 an oz dry, not worth it. And then I noticed something - The first ~3 inches of top substrate were airy, and nice. Slightly moist, and fluffy. But the other ~60% of substrate on the bottom were.. compacted. Like a brick. It wasn't WET, it was perfectly moist, but I could grab chunks out of it, and they crumbled after I pressed on them. It was all just a big chunk of substrate.

May this be a problem for the other plants, too? The seem fine, but I know that compacted substrate isn't ideal. The substrate I'm using is BioBizz All Mix, it's an "organic" peat moss substrate with worm castings, perlite, and a starter nutrient mix.

Now I do water as someone should in the beginning - Watering can with a diffusor, so it just rains water, rather than a big wave of water at once. I don't know why my substrate got so compacted on the bottom, especially because I already take upmost care when filling the fabric pots to not compact the substrate.

Can someone tell me more about this? Will my roots be fine with such a compacted soil, can they grow through it?

 

[Sunasun]

Okay, next update: 3 out of 4 plants survived, one is 100% stunted and pretty much a failure, with the same yellowing as always. The other 3 look fine so far.

I'm already germinating a new seed in a solo cup, just trying it differently this time with one transplant, going against the "bro science". It'll probably poke out tonight.

With this, I will change to a 4gal pot, instead of the 7gal pot I already have filled, so I dumped the substrate out of the 7gal onto a big plastic sheet and, coming with it, I.. killed the old seedling. It's day 10 now, and it looked like day 3 or 4 at most, and that'll just make everything worse with an autoflower. Trust me, I did go through with it once, and ended up with 1/2 an oz dry, not worth it. And then I noticed something - The first ~3 inches of top substrate were airy, and nice. Slightly moist, and fluffy. But the other ~60% of substrate on the bottom were.. compacted. Like a brick. It wasn't WET, it was perfectly moist, but I could grab chunks out of it, and they crumbled after I pressed on them. It was all just a big chunk of substrate.

May this be a problem for the other plants, too? The seem fine, but I know that compacted substrate isn't ideal. The substrate I'm using is BioBizz All Mix, it's an "organic" peat moss substrate with worm castings, perlite, and a starter nutrient mix.

Now I do water as someone should in the beginning - Watering can with a diffusor, so it just rains water, rather than a big wave of water at once. I don't know why my substrate got so compacted on the bottom, especially because I already take upmost care when filling the fabric pots to not compact the substrate.

Can someone tell me more about this? Will my roots be fine with such a compacted soil, can they grow through it?

Stop mixing soil mix substrates for now. Try just using one all the way through your pot.

 

[Acid]

Stop mixing soil mix substrates for now. Try just using one all the way through your pot.

I feel like there's a huge language barrier here, maybe because English isn't my first language. Almost everything I say gets misunderstood, almost all the answers to my comments talk about something completely different than what I was saying.

I did not mix any substrate, never mentioned mixing any substrates together. I did mix substrate in the beginning of this grow, but it was both the same peat, one just not as nutrient rich as the other. All people do that with this substrate if they wanna use it, as they're basically 1:1 the same. The only difference is the amount of premix (nutrients) in the substrate. I didn't mix organic peat moss with salt-based enriched coco substrate or anything, I literally just mixed the same substrates, with one having no nutrients, which is recommended even by biobizz if one of the substrate is too hot.

To explain my question simply and short:

One of my seedlings died. I took it out of the substrate. I got a different, smaller fabric pot to fill the substrate in, as I felt like changing from 7gal to 4gal for once.


When I took the substrate out of the old pot, it was airy and moist on top, and hard as a brick on the bottom, but not drenched or anything, also just moist. Around 60% of said substrate was hard as a brick, I could take it out in chunks and crumble it between my hands, even though I took uppermost care to not compact it in any way.

Why did this happen? And is this normal?