Why is my plant so small?

[SirBubblesthe]

New grower here. I recently started growing 5 feminized Super Silver Haze plants indoors and in soil.
I've made a few rookie mistakes, but as a whole the plants seem very healthy and are growing fast, except for one. The problem plant (who I'm calling Runt), germinated first, but has ever since been growing slower and smaller than the others. The only difference in Runt's treatment was that she got her own light (20w, 900 lumen CFL) for about a week while I repotted the other 4 for the first time (they were 2 weeks old) and put them under higher power LEDs.
The plants are a month old now, and while the other 4 are almost a foot tall, Runt is only around 4 inches (although at almost the same growth stage). Runt also has light green-yellow leaves while the others are a very dark green.
I'm pretty sure Runt isn't nutrient-deficient (I recently flushed all the plants after discovering a bit of nutrient burn), I don't see any mites or bugs, and the soil pH is almost ideal at 6.8-7, so I'm stumped at what is causing her to be discolored and so much smaller than the others.
Any ideas?

The soil I'm using is organic, with no time release fertilizers, and the nutrients I'm using are Earth Juice Grow, Bloom, and Catalyst.

 

[Rifleman]

Photos will go a long way towards a diagnosis.

 

[Razya]

hı ım a newbee as well ım waıghtıng wıth u on the same answer to be replıed theır not tall but very bushy and started to get cracks ın theır leaves as ıf they are burstıng ,lıke u dıd ı just fed them twıce untıll now and theır 4wks old . :/

 

[SirBubblesthe]

Call me an idiot, but I have no idea how to post photos in here.

 

[SirBubblesthe]

Yours honestly look like they need more water. If the leaves are cracking, that means they're really dry, and I don't see signs of nutrient burn. The chunk that's been taken out of the leaf on the bottom almost looks like its been eaten, though.

 

[Razya]

ı have had them under cfls and ı accıdentley dropped a warm bulb on ıt ,ıt ıs rıpped a bıt more wıthın a week ,ı dont thınk ıts overwaterıng tough,theır soıl ıs really wet and ı am more concerned for overwaterıng .ı read somewhere that ıt can be from overfeedıng but ı gave theır second feedıng just today :/ and ı was already dreamıng of smokıng my own herb already , yours could be rootbound or calmag deffıcıency tough ? ı myself havent add any calmag yet ı have ordered ıt onlıne and stıll waıgtıng -_-

 

[Rifleman]

Photo Gallery Guide - How to Resize, Upload & Post Photos

 

[SirBubblesthe]

It may be excess heat, then. As my original post said, I've pretty much factored out any nutrient deficiencies since the nutes I have cover just about everything, and I just treated the plants for nutrient burn.
The pot its in is a 1 gal, so highly doubtful that its rootbound. Its been small and yellow all through its development, with prompts me to think that I may have somehow hurt it while it was still young.

 

[SirBubblesthe]

Here it is. I sort of figured it out.
I'm 21 years old and I can't technology halp

 

[Rifleman]

Looks wet. Too wet roots will lock out nitrogen.

 

[Razya]

ı am new lıke u are but ıve heard not to gıve seedlıngs nutes wıthın fırst few weeks ,maybe ıts just stressed and takes a bıt longer to grow ? seems very lıkely but ıdk ım waıtıng for the pro's to help us,ı hope lols

 

[Razya]

do u by chance know what my ıssue would be ??

 

[OlderGrower]

The soil I'm using is organic, with no time release fertilizers, and the nutrients I'm using are Earth Juice Grow, Bloom, and Catalyst.

If you are in a 1 gal pot and using organic soil I would guess you may be over feeding her. I grow in FF ocean harvest potting soil and do not give my girls anything for the 1st 4 weeks since there is plenty of nutrients in the soil to begin with. After 4 weeks I go to a couple of weeks of 1/4 strength, then the next 2 weeks at 1/2 strength to give the girls a chance to finish up what is available in the soil to begin with. Now if you are using an inert organic soil like say coco then I would start them out on Nutrients sooner but I would still start them out at 1/4 then 1/2 just to get them use to their feeding.

 

[Rifleman]

Razya, more info please. Photos of whole plant? Sounds like dry, or heat, but can't tell for sure from the limited info & photo. The photo actually looked good.

 

[OlderGrower]

Hey Sir Bubble?

How often do you water and what method do you use to determine when to water?
I started with the finger in the soil when I first started but find the lifting the pot and going by weight to be more effective.

 

[Emilya Green]

let's just get it all out on the table... how often do you water? How do you determine that it is time to water? How much do you give when you do water.

 

[SirBubblesthe]

I just flushed it. Its going to look wet for a bit. This has been happening all through the life of the plant, not just recently.

 

[SirBubblesthe]

I stick my finger an inch down into the soil, and if the soil is not moist, I water the plant. This is usually every 5 days or so. There is nutrient burn on the lower leaves, so I flushed the plant with water until about a cup dripped out of the bottom, and I mixed in a little fresh, dry soil afterwards. This is why it looks very wet. I usually water the runty plant with about a quarter cup of water, the larger plants with a half cup.

 

[SirBubblesthe]

The plants had calcium and phosphorus deficiencies at about 2 1/2 weeks, which is when I gave them their first nutes. The small plant didn't have the same deficiencies and thus I only very recently starting giving her nutes about a week ago at 3 weeks.

 

[SirBubblesthe]

Thanks! I'm trying to correct that problem currently. She grew out of her old pot (a solo cup), so I transferred her to the same size as the other plants at about 2 1/2 weeks. Maybe I should have waited to add her first dose of nutes, but I thought at first that the problem might have been nitrogen deficiency, so that's why I started early. She won't be getting any more until I see improvement.