Does this plant have some kind of nutrient deficiency? Yellowing first true leaves.

[zuraya]

I started with three atomical haze seeds.

I germinated and planted two seeds in a soil composed of equal parts homemade organic compost, perlite, and coco coir. Soil pH was about 6.4-6.5 and recently, on the 17th day, I successfully transplanted to larger pots. Here are photos I just took inside the grow tent on day 19 (the white light doesn't do justice to the vivid green when under warm lights)

Plant 1

Plant 2

My question is about the third seed, which I planted in a mix of perlite and commercial organic soil. This plant is notably smaller than the other two, and is still in the original cup now on the 19th day.

My goal with this third plant is to use fertilizers instead of compost for nutrients to see the difference.

The cotyledons turned yellow on all three plants, but on this third plant the first set of true leaves is now yellow and I see discoloration on some of the other leaves, as you can see below

Here is this same third plant in different lighting

In these photos, it doesn't look as yellow as I perceive it in real life.

You can see the discolorations from the top view.

My question is: is there a problem here?

By the way, the plants look so much more beautiful in this alternative lighting (overhead warm lights). I didn't take a picture of the first two because I don't feel like lifting their new containers out of the tent for now, but I can do this if anyone is curious.

Additional details

I'm using Migro Aray 3 (250W) running at 60% 40cm above the plants, as per the user manual.

The tent is a 1.20m x 1.20m Vivosun air-cooled with an AC infinity intake and exhaust, plus two small Vivosun oscillating fans inside.

This is my first grow where everything seems to be in place. Technically, it is my second grow, though in my first grow attempt earlier this year I unfortunately found out that my lights were way too strong for seedlings and early vegetative stage (Apache Tech AT600 monster lights, no dimmer, burning up the baby plants even 1.5m above them) and so I had to postpone to now.

After noticing the yellowing plants, I did a bit of research and figured the third plant could have a nutrient deficiency. I don't know how good the commercial soil mix is. So yesterday I started adding Remo nutrients to the water for the third plant (micro, grow, velokelp, magnifical).

Is this a good idea at this early stage?

Finally, can I consider all three to be in vegetative stage already? I am asking so I can confirm that I can be using the Remo nutrients, as per the following chart from their website

 

[Roy Growin]

Looks fine, carry on

 

[BigBudsBunny]

lookin good

 

[Sueet]

Yes they are ready for food. Yes this is the beginning of veg.

You didn't mention if you are adding cal-mag? Also, are you pH'ing your inputs?

Other than that, I was just wondering if you were aware of the seedling hiding under plant two's wing there?

 

[zuraya]

Yes they are ready for food. Yes this is the beginning of veg.

You didn't mention if you are adding cal-mag? Also, are you pH'ing your inputs?

Other than that, I was just wondering if you were aware of the seedling hiding under plant two's wing there?

1) If I understand correctly, by food you are referring to added nutrients.

Plants 1 and 2 are growing in a homemade soil mix that I am supposing is very nutrient rich and I won't be feeding them any extra.

I've been composting for a few years now and my experience has been very positive with my compost + coco coir + perlite mix for other general plants.

Plant 3 is to be grown differently, in a 70-30 coco coir + perlite mix with Remo nutrients (including Cal-mag, here are all the products I will use)

I'd like to experience for myself what it is like to grow in this soilless way.

It is day 20 and I will transplant plant 3 today to a larger fabric pot.

That being said, I do have a question. Plant 3 has been in commercial soil + perlite up to this point. Is it ok to place it in a soilless medium starting with the transplant today?

I am also deciding whether to add just a tiny bit of my homemade soil in the coco-coir. Apparently, this isn't necessary though, since the lineup of Remo products seems to be all that is required.

For me it comes more naturally to view the growing process in terms of the biodiversity present in a soil that is alive not sterile. So, growing in just coco coir + perlite really is more challenging for me to wrap my head around.

2) I starting pH-ing my inputs yesterday, coincidentally.

The tap water I am using (which in my house goes through an "ultrafiltration membrane" plus two carbon filters for chlorine) has a pH of 6.8 according to my measuring instrument.

I measured the pH of the water + Remo nutrients that I am using, and that came out to 5.9, which according to what I've read so far seems perfect for the soilless medium of coco coir + perlite.

3) I did notice the little seedling. I pulled it out. The compost I make has seeds from the organic foods I put in it, usually pumpkin or tomato or something like that.

 

[Sueet]

1) If I understand correctly, by food you are referring to added nutrients. - Yes I meant nutrients.

Plants 1 and 2 are growing in a homemade soil mix that I am supposing is very nutrient rich and I won't be feeding them any extra.

I've been composting for a few years now and my experience has been very positive with my compost + coco coir + perlite mix for other general plants.

Plant 3 is to be grown differently, in a 70-30 coco coir + perlite mix with Remo nutrients (including Cal-mag, here are all the products I will use)

I'd like to experience for myself what it is like to grow in this soilless way.

It is day 20 and I will transplant plant 3 today to a larger fabric pot.

That being said, I do have a question. Plant 3 has been in commercial soil + perlite up to this point. Is it ok to place it in a soilless medium starting with the transplant today? Sorry I don't know, I have never tried to start a plant in soil and transfer it to soilless. Probably the plant will figure it out, but I can't even say if you should clean the soil off of the roots or leave the rootball intact. I have no idea which one would be more beneficial. IF it were me, I guess I would clean the soil off before transplanting.

I am also deciding whether to add just a tiny bit of my homemade soil in the coco-coir. Apparently, this isn't necessary though, since the lineup of Remo products seems to be all that is required.

For me it comes more naturally to view the growing process in terms of the biodiversity present in a soil that is alive not sterile. So, growing in just coco coir + perlite really is more challenging for me to wrap my head around. - The key is the form the nutrients take. Without microbes to do the heavy lifting of processing the nutrients for the plant, we instead feed them with nutrients that have been chelated in a way that allows the plant to uptake them without needing to be processed. This process uses salts to deliver them, and can over time build up in the medium which then needs to be flushed out periodically.

2) I starting pH-ing my inputs yesterday, coincidentally.

The tap water I am using (which in my house goes through an "ultrafiltration membrane" plus two carbon filters for chlorine) has a pH of 6.8 according to my measuring instrument.

I measured the pH of the water + Remo nutrients that I am using, and that came out to 5.9, which according to what I've read so far seems perfect for the soilless medium of coco coir + perlite. Yea that works for the plant in the soilless, but for the other two, long term you might have some minor pH problems if you leave it at 6.8, typically you want to aim for 6.3 in soil to assist the plant in being able to access each individual nutrient.

3) I did notice the little seedling. I pulled it out. The compost I make has seeds from the organic foods I put in it, usually pumpkin or tomato or something like that. Aww, I thought it was a little weed sister, like you put two seeds in at once and one popped slow.