First Grow Journal - Advice Appreciated

[yassem]

Hi there,

TLR I'm new here. I think my plants experienced heat stress. What else should I do to maximize their chances of recovery? Also, they are wildly different when it comes to size, will that be a problem?

INTRO:
Hi there, this is actually my first grow and my first post here and I am a bit anxious (I don't really use any kind of forums that much, so I'm not very good with the netiquette). I'm not even sure if I'm posting in the right place TBH. Anyway, I do realize that many of the issues I describe below have been answered both here and elsewhere but I assure you that I've done some research. I do feel however like there are still some unanswered questions, especially since in many aspects there are lots and lots of opinions. I've been reading this forum for quite some time, and it actually looks like a good place to get some extra opinions, not to mention some valuable feedback. P.S. I don't know all the specific terms in English, so I might have to use some wiki/google translating, sorry for any mistakes. THANKS IN ADVANCE!

CURRENT STATE
Fig. 1 (photos at the bottom)
I have received most of the set-up from a friend, though I made some improvements.

• Grow box: a 40cm x 40cm x 1.5 m (15" x 15" x 5ft) wooden grow box, white foil on the inside
• Lamp: 400W HPS, 18h a day at about 40cm (15") - was at about 20cm (7.5") before the heat stress.
• Exhaust: 2 (tube?) fans, ~103 m³/h (if I recall correctly). I also have two much weaker fans, which I now use inside the box the blow on the plants - I installed them AFTER the heat stress.
• Soil: 3x11L (2.9 gal.), it's a basic flower mix (just a little bit on the acidic side of the spectrum). I have NO perlite (I know - bummer, but I don't want to change the soil now unless absolutely necessary), I have expanded clay (LECA) on both the bottom and the top of the pots. I have no idea how to call it in English, but the pots are made of plastic that has lots and lots of big holes in it.
• Plants: 3 plants, OG Kush, femi, 14 days old (veg)
• Fertilizer: After one week I have started introducing grow fertilizer, starting with about 0.5mL/1L (0.0005%), right now at about 1mL/L (0.001%). I am using BIO-BIZZ organic fertilizer (it says on the pack to use 1-2mL/L during veg)
• Water: My tap water is extremely hard, so I don't use it. I've been using a mix of bottled water and demineralized water (I aim at pH ~6.8). I water them every two days now, about 0.5L (0.13 gal.) each. I also spray(?) the plants with demineralized water after turning of the lights.
• Humidity: Varies 25%-40%, I have no means of controlling humidity.
• Temperature: MY MAIN CONCERN. I've got two thermometers (one in hygrometer), and I don't think they are very accurate. The results vary by 2-3 deg. C sometimes. Nevertheless, on two occasions the temperature shown reached 34 deg. C (93F). I've installed the new fans, and now it stabilized at about 26 deg. C (80F).
• I have also tried to increase CO₂ by placing a bottle field with water, sugar and yeast in the box, but now that I think about it it seems pretty naive.

CONCERNS
I've got two main concerns.

The first one, mentioned above - possible heat stress. On two occasions the temp. in the box reached 34 deg. C (93F) with the light quite low (about 20cm/7.5"). I've got three plants - Bójka, Bajka and Brawórka (names of powerpuff girls in Polish).
Brawórka (the smallest one) Fig. 2 - got it worst. It looks crippled, with the first pair of leaves visibly burned - Fig. 3. Strong discolouration, loss of turgor (?), looks quite dehydrated but I'm afraid to over-water. This is also the plant that was dircetly under the lamp, but it was also the smallest one to begin with.
Bajka (by far the biggest one, more on that later) Fig. 4 - doesn't look well either. It is huge, much much bigger then her sisters, but still, she got it pretty bad. The first signs were leaves curling up along the longitudinal (?) side. Now the leaves returned to pretty much normal shape, but the first pair of leaves are very discoloured, browning at the ends - Fig. 5.
Bójka (the middle one, small) Fig. 6, 7 - is just mildly discoloured. She was the one closest to the door, so it might have been cooler for her.
First of all, am I correct to identify the situation as heat stress? I also thought of nut. burn, but I tried to be really careful with the fertilizer. Secondly, I there still chance to save them? Bajka and Bójka doesn't look that bad, but Brawórka (the smallest one) seems almost destroyed. The opinions on this matter in other topics and forums are not consistent - what should I do to maximize the chance of them healing from this?
Should I cut off the brown part/the damaged leaves?

Secondly, the size of the plants. There is a huge difference in size, Bajka (the biggest) Fig. 4 vs Brawórka (the smallest) Fig. 2- it doesn't even look like one species. Assuming all of them, or at least two of them, survive, what is the way to go here? Should I wait for the smallest one to reach enough size or should I should I rather start when it is optimal for the biggest one? How bad is prolonging veg?

If I've omitted anything crucial please tell me so I can elaborate.

^^^Those are my main concerns, if someone could address them I would be really grateful I would also like to share my plans for the future with you. If someone finds the time and will to read this far and point out any mistakes I would be VERY happy.

1. At this stage I am waiting for the plants to grow a little taller and I'm going to start LST to use the surface more efficiently.
2. I will water the plants every two days, with increasing amount of water
3. I will maintain 40cm (15") gap between light source and the plants for now, at least until they recover
4. For now I am not going to cut off the damaged parts, not the leaves (unless advised to do otherwise)
5. I will be starting FLO in about 14 days, to give the little one time to recover (maybe?) - they will be 4 weeks old by then
6. I will flush the plants about one week prior to harvest

If there is anything you think I'm doing or plan on doing wrong please tell me so. This is my first time and I'm eager to learn more. Share you opinions with me, the more the better.


PHOTOS
Fig. 1, The setup


Fig. 2, Brawórka - the small one, severely damaged


Fig. 3, Brawórka's leaves - discolouration, lack of turgor


Fig. 4, Bajka - the big one, quite damaged


Fig. 5, Bajka's leaf, discoloured, a bit of curling up remains


Fig. 6, Bójka, small but the least damaged


Fig. 7, Bójka's leaf, traces of discolouration

 

[Kalimaki420]

re: Possible heat stress - What to do next? Bonus questions

to 420 yassem

Most was heat stress, try to stay under 30°C and keep 30cm at minimum distance to canopy.

Don't water till pot get very light, I wait till leafs hang down a bit in veg.
At that stage I water 1x peer week, nutes from week 3 or 4 soil has enough for the first weeks.

Cut leafs of later, affected leaf wont recover and look worse over time so only look to new grow.
I would train the big one and let the other recover and go to bloom in about 2-3 weeks.

If possible try to get Rh to 50% under 40% plants don't grow optimal.
I hang a towel in a bucket of water near a fan, often helps to not go under 40%

 

[Papageno]

Re: Possible heat stress - What to do next? Bonus questions

At that age cut nothing off. In general cutting doesn't help. There are only a handful of very specific ways to cut the plant that are deemed positive for growth in the long run.

DarkGrow is correct on all that stuff...but mostly what you got wrong is watering. Watering every 2 days will slow growth. In the wrong pot and soil it can cause rot and kill the plant. At a bare minimum it will inhibit potential root growth. The whole point of veg is to build the foundation from which to grow the flowers. 80% of which is the roots (not in mass but in importance). If you water it less it will grow roots significantly faster and have a much larger root ball when it stops growing roots and focuses on the flowers. The size of the harvest is limited by the root mass. So in Veg the goal is to grow huge root mass.

I recommend you ask a moderator to move this to a journal and you can keep the questions coming.

 

[yassem]

Re: Possible heat stress - What to do next? Bonus questions

First of all, thank you guys so much for your responses.


It's good that I asked this question here because I was just a step away from cutting the brown parts off - it's something I've read on another forum, but I guess I didn't take the plants' age into the account. I also tried hanging a wet gauze, and it did raise the Rh but only ever so slightly (like 3-5%), so I gave it up, thinking - "who knows what could end up growing on such a thing... fungus or something...". Anyway, I think I might give it another try.

As for the watering, I opted for watering less and more often cause I was advised so earlier - I was told that low Rh, high temp and the type of pots I'm using (the ones with lot's and lot's of holes, pics at the bottom) lead to much more water evaporating, but I guess I will re-evaluate my approach in that matter.

As for the nutes, is adding fertilizer at this point just a waste, or is it actually dangerous? I am cautious about not nut.-burning the plants, the soil is not a specialized one (I'm afraid it might lack some micro-elements or whatnot), and the timetable I got with the fertilizer does say to start at week 2 of VEG with 1mL/L (0.001%). They received fertilizer 3 times right now, each time less than the recommended dosage. I have no problem with wasting the fertilizer (mL here, mL there is not much), but if it is risky of course I will refrain from giving them any more for a couple more weeks. I don't suppose there's anything like a withdrawal syndrome, right?

I also followed VilliageIdiot and contacted the moderator about moving this thread to journals, so I guess I'll keep on posting here with current updates and issues I might run into. All in all, I must say that I am very pleasantly surprised by this forum! Thank you very much!

__________
My pots:

Does that kind of pot have a name? It would be useful for future reference.

 

[AKgramma]

Re: Possible heat stress - What to do next? Bonus questions

if you're afraid that a gauze or towel might grow mold, try putting a gallon of water in an open pail near your fan. This will evaporate and raise the RH. Unless you live in a very wet area, you won't develop mold. But you might have to scrub the pot out with bleach water occasionally to kill algae.

 

[yassem]

Re: Possible heat stress - What to do next? Bonus questions

try putting a gallon of water in an open pail near your fan

Tried that earlier as well, with no success but that was before I installed the fans on the inside. I guess I'll give it another shot then.

But you might have to scrub the pot out with bleach water occasionally to kill algae

I've heard about algae in hydroponics, so I wasn't really thinking about it until now. Just to be sure, you mean that during this grow I should scrub the outside of the pot with bleach water? Should it be something I do preventively or only once I notice algae building up? Won't the bleach enter the inside of the pot through the holes? Thank you for this suggestion.

 

[AKgramma]

Re: Possible heat stress - What to do next? Bonus questions

You wash inside and out, rinse well, then fill with tap water. And a good pail should have no holes!

The fan will distribute the moist air and increase evaporation.

 

[Papageno]

Re: Possible heat stress - What to do next? Bonus questions

Yes nutes are dangerous at that stage. The seed has enough to get very far otherwise it wouldn't work in nature.

The preferred pots for cannabis are fabric posts. There are other fancier pots and I can explain why those are not really meant for Cannabis and why fabric are better. Just use fabric pots. If you can 't get them those will work fine.

I put rocks on the drip pans then the pot on the rocks so that when I water I can get the proper run off...proper watering is around 15% or more run off in most kinds of soil growing

I hang towels in front of the fan and around my SCROG rack. I have towel in the bucket wicking water up hanging over an inlet vent. I have Hydroponic Grow Stones in pans in front of the fan that are full of water.

 

[David Bowman]

Hope all is well in your world.

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Sending you lots of love and positive energy.