First grow, Deep Chunk open pollination

[greencalyx]

Here is an update on the plants that looked unwell. Everyone else had bone dry soil and got watered today, aside from these two. They still had a hint of moisture so I held off watering.




I could be heat stress as well
I have the light at about 300w now and now it gets about 80-90f in there during the day. I don't think that's TOO hot, but maybe. The extra heat has been messing with my vpd target, so had to add more humidity. Maybe vpd got a bit high at times.

Here's a snapshot of an average day with the min max values in the corners:

 

[revegeta666]

300w sounds like a lot for such small plants. My bet is on that. By the looks of the leaves the issue is progressing quickly be careful. They have intervenal chlorosis which is a sign of magnesium deficiency. You can correct this with Epsom salts.

 

[greencalyx]

Yeah, I thought it looked like mag deficiency too. But thought it weird that only two plants were experiencing it. Those two were definitely more moist than the rest. Maybe overwatering caused a temporary nutrient (mag) lock? I'll definitely give these some Epsom.

The light is 40 inches above the tops of the plants. Should be the equivalent of 75w at 20 inches by inverse square. I think that's OK, but, then again, I have no experience with cannabis. What wattage do you use for this stage?

Another thing worth noting is that I haven't really been using the exhaust fan much. It's triggered just to turn on to its lowest setting for just a few minutes when the humidity I set is reached. Otherwise it's off. Can't keep the humidity in check otherwise.

I bought a humidifier online and it's on the way. Should allow me to run the exhaust more and get more fresh air flowing.

Also, co2 levels. I have a co2 level sensor in the tent. Not sure how accurate it is. It levels out at about 425ppm in the tent, lights on. It gets as high as 700ppm lights out. My ambient level in the house is over 1000ppm, which is kinda alarming. I think both me and the plants will benefit from a constant exhaust and the tent being a (reverse) lung for the house. More humidity will be nice for the house, too. It's subzero outside.

 

[Limeygreen]

Just looks like potassium deficiency to me, during the transplanting and then a bit too much water can make it happen.

 

[revegeta666]

@greencalyx check the pictures in these 2 articles and it should be pretty clear it is a magnesium deficiency.

Magnesium

How to fix Cannabis Magnesium Deficiency (Mg) Pics & Symptoms

Does your cannabis plant have yellowing lower leaves between the veins? See pictures of a magnesium deficiency and learn the easy solution.

www.growweedeasy.com

Potassium

How to fix Cannabis Potassium Deficiency (K) Pics & Symptoms

Leaves with a potassium deficiency have yellow, brown, or burnt edges and tips. It may look like nutrient burn, but the leaf margins also turn yellow.

www.growweedeasy.com

Don't worry about co2 levels or vpd, try to get the basics in check. Air, water, light. Extraction being on for only a few minutes doesn't sound too good. I would much rather have too low humidity but with good airflow.

The fact that it's only 2 plants affected sounds weird,, but it could be that you're not recognizing the early signs of the deficiency (intervenal chlorosis). Check the pics in the article I linked and it would be also helpful if you could upllad a couple of pictures where we can see a general view. Hard to say if there's too much light, if we can't see how much space the plants are taking under the lights. Also a detail of the leaves of those you consider healthy, just to make sure they are.

Do you also have a fan inside the tent, moving the air around?

 

[VerdantGreen]

Nice project - i did this about 10 years ago and the seeds are still going strong!
If the two plants that are exhibiting problems are the two where the soil is wettest, it is a possibility that fungus gnat larvae are the problem.. nibbling the roots and making the plants struggle to take up nutes. Turn them out of the pots carefully and look carefully around the inside of the empty pot and the rootball for tiny worm/maggot type things moving. Try to let the pots dry out a bit as the larvae can't live in dry - ish soil.
Those two are also possibly the ones with the least vigorous root growth and sometimes they can be more sensitive to a rich soil than the others. Just a couple of thoughts.
Also i haven't read the whole thread but if you intend to simply leave the males in the tent to flower with the females you will get a poor number of seeds as DC has few pistils.. better to keep the pollen out, collect it, and then pollinate at about 4 weeks when you will have more pistils and thus more seeds.
VG

 

[greencalyx]

@revegeta666 I agree. Definitely looks like clear magnesium deficiency. I'll definitely give Epsom water when I water later today after I go to the store.

Thinking about it more, it makes sense. I know I have plenty of calcium in my water, but wasn't able to find out the mag levels. Same with my soil. The soil does use worm castings, but there is no quantified amount of mag listed anywhere. Could be its a deficiency all the plants are experiencing, but just the more vulnerable (overwatered?) ones are showing it more. I didn't think fox farm soil would be deficient in anything though... but it definitely appears the plants are deficient

There are two that are heavily affected (pictured a few posts above) along with 3-4 somewhat affected. Like these:



Here's the best I can do at a group photo. There isn't much space behind me to back up and get a proper shot. The plants are more or less evenly spread about the 5x5ft area


Light 40inches from top of plants


Also, it's a fairly large fixture. 4x4ft I believe. So it will have less intensity than a smaller fixture of the same wattage.

Here's some of the better looking plants

Don't worry about co2 levels or vpd, try to get the basics in check. Air, water, light. Extraction being on for only a few minutes doesn't sound too good. I would much rather have too low humidity but with good airflow.

Forgive me for sounding dense, but aren't co2 levels and vpd some of the most important aspects of air for plant growth? And doesn't good airflow just mean that you are constantly replenishing the co2 that was used up in the tent, with more co2 from the air outside the tent?

It's winter here and the rh outside the tent is 20-25%. I have tried running the exhaust on low for about half and hour just to see, and it brought rh down to the low 30s and seemed like it would go lower, but I turned fan back to its regular schedule.

I did buy a humidifier online, and it is on the way. Should help me keep the exhaust on longer.

Also, I do have a six inch oscillating fan inside the tent that runs 18hrs a day

 

[revegeta666]

Could be its a deficiency all the plants are experiencing, but just the more vulnerable (overwatered?) ones are showing it more.

Yes, it could be. They do show early signs of Mg deficiency and leaves look puffy which does suggest overwatering, unless you took the pictures just after watering. Having magnesium deficiency symptoms doesn't necessarily mean the soil is lacking magnesium. Nutrients will stop being available for other reasons such as pH imbalance, root issues (could be if overwatered and could be if fungus gnats as said earlier), or antagonism with other nutrients. In this case, an excess of calcium could prevent magnesium assimilation. Maybe your water does have too much calcium, as we were discussing earlier? Depending on the content in the soil, it could cause a lockout.

Personally I would reduce water amount and frequency, dilute it with softer water, and correct the deficiency spraying Epsom salts. Should get fixed with 3 sprayings, one every 3 days. I dissolve 1 tablespoon of salts in 1 gallon of warm water, to help dissolve the salts, then let it rest until it's room temperature and spray, especially under the leaves. When the next transplant comes, that will help with the deficiency also.

aren't co2 levels and vpd some of the most important aspects of air for plant growth? And doesn't good airflow just mean that you are constantly replenishing the co2 that was used up in the tent, with more co2 from the air outside the tent?

Maybe that's what it means, yes I would agree I guess. But you don't need to measure the co2 level or vpd in your first grow. What I meant was to focus on the most basic aspects, especially amount and quality of water (ie not overwatering or too hard water), correct distance and intensity of light (should be mild in this stage IMO), and airflow. When I used to grow in a tent, I would have the extraction on 24/7. I suggest you have both the fan and extraction on at all times and plants will get happier. I would add at least another fan as well. As for the VPD, plants thrive in Afghanistan with worse RH than 30%. Stagnant air is more harmful than low humidity. Optimal temperature and RH will make your plants go in turbo mode, but airflow is most important IMO. Give it a try, I bet you will see them happier in 3-4 days. Soil will dry earlier as well and will help if there is indeed overwatering.

Lastly, adding the humidifier will help correct the VPD and make the plants grow more vigorously yes.

Edit - forgot the light. Distance looks great, I would take the potency down a notch if you can. If it's too litltle, you will see the plants stretch a little bit. If that's the case turn it up a notch.

Edit 2 - just read you were going to water with epsom salts. That doesn't work very well man, spraying is much more effective. If there's a problem in the soil you could be making it worse. Just spray it will be easier on the roots.

 

[laszlokovacs]

Hey man, keep up the good work. Reading this thread made me pop some beans 3 weeks it looked like so much fun. Also had to grab a pack of deep chunk before they got sold out.

Odd that just 2 have those problems. You mentioned a while back you put two soils on top of each other for awhile. Could you have possibly not have completely mixed the mediums when repotting (i.e. those two are in soil from the bottom of the mixing container and uneven, or two layers of diff soil etc...). I could be remembering wrong but i thought i read you did this- disregard if you didnt.

Personally I would reduce water amount and frequency, dilute it with softer water, and correct the deficiency spraying Epsom salts. Should get fixed with 3 sprayings, one every 3 days. I dissolve 1 tablespoon of salts in 1 gallon of warm water, to help dissolve the salts, then let it rest until it's room temperature and spray, especially under the leaves. When the next transplant comes, that will help with the deficiency also.

I would agree try to go easy on the watering- they look pretty good though for the most part. Try not to water to runoff frequently until the roots reach the bottom of the pot.

 

[greencalyx]

Here's a week five update:



Here's the two in the bottom left that I couldn't get in the above shot:



I gave the sickly looking plants some magnesium sprayings on Sunday, and will give them some more tonight.

Been holding off on watering, especially the two overwatered ones. Their pots are dry at the top (and a couple inches down), but still have a little heft. The others have gotten light watering, like a cup at a time. I want to let the bottom of the pots to dry up a hair to get more air down there.

I have been running the exhaust on low continuously and I got a humidifier I've been running since yesterday.

 

[greencalyx]

Plants aren't looking too happy this morning. I am hoping I was just too cautious with watering, and now they are thirsty?

 

[pipeline]

Getting some wide leaflets going on! Thanks for the updates!

Yeah I have been noticing the media doesn't look really settled like it should. Make sure you water to saturation which means water will run out the bottom. Allow a couple/ few days to dry then water heavily again.

Lighter watering may be alright in early stages to preserve air and porosity in the soil, but once they are growing well (4wks) heavier watering is needed to make sure all the soil is replenished with water and nutrients.

 

[revegeta666]

If you are unsure of when and how much to water, this trick works well - lift the pots often until you get a feel for their weight. The morning you lift them up and notice how light they are is the day you should water. There's a very noticeable difference in weight.

 

[laszlokovacs]

Do you know what your runoff pH is? Some of those lower leaves look a bit weird.

Letting the pot dry off too much can definitely cause worsening symptoms to appear in the plant when there are nute issues, its possible.

Revegeta is on point about getting a feel for when pots are light, but make sure they're getting enough water because they are fairly far along in veg

 

[Limeygreen]

Try upping your feed and make sure not too wet or too dry imo.

 

[Creeperpark]

Here is an update on the plants that looked unwell. Everyone else had bone dry soil and got watered today, aside from these two. They still had a hint of moisture so I held off watering.

View attachment 18813474
View attachment 18813473

I could be heat stress as well
I have the light at about 300w now and now it gets about 80-90f in there during the day. I don't think that's TOO hot, but maybe. The extra heat has been messing with my vpd target, so had to add more humidity. Maybe vpd got a bit high at times.

Here's a snapshot of an average day with the min max values in the corners:
View attachment 18813487

If you do a pour thru on those two plants you may find that the pH has dropped lower than the other plants.

 

[greencalyx]

Definitely ordering a ph meter now, don't have one.

Watered with distilled/RO water this time in case my tap water is to blame. Gave them a very thorough watering

Thanks for the help everyone!

 

[laszlokovacs]

Definitely ordering a ph meter now, don't have one.

Watered with distilled/RO water this time in case my tap water is to blame. Gave them a very thorough watering

Thanks for the help everyone!

You can also buy test solution drops, where you add a few drops and the color will show you pH, available at a lot of pet stores for fish tanks or online for a couple bucks. I dont think a pH meter is too expensive but they can be unreliable if the calibration gets messed up.

 

[pipeline]

I forgot to mention that. Feeling the weight is the best gauge of moisture, but yeah try not to let it overdry of course, so regular container weight checks will help you get a feel for it.

Also use your finger to feel the moisture in top of the soil and beneath the surface, to get an idea of how much moisture is available.

May be good to top dress with a little nitrogen dominant fertilizer like guano or compost. Could also feed with fish or some type of liquid N source.

I had similar yellowing on my plot last year from lack of watering and fertilizer. Put down some compost early September and got serious about watering them heavily and infrequent, about once a week. Helped the plants stay green.

 

[revegeta666]

Definitely ordering a ph meter now, don't have one.

That's what I meant the other day about getting the basics in check first. There's no point in checking co2 levels or vpd if you don't know what pH you are watering with. You should have said that first as well. I assumed you were measuring it.

May be good to top dress with a little nitrogen dominant fertilizer like guano or compost. Could also feed with fish or some type of liquid N source.

They do look like they are asking for nitrogen but taking into account that he is using a commercial mix I would assume there is nitrogen available in the soil but the plants may be not able to intake it due to wrong pH. If you don't know the pH it could be anything really.