My plant

Can't answer your question, but flip that credit card over, give me the security code, enlarge the picture, and I'll get back to you.............

 

Seriously, a pic of the other plants and a close-up pic of the plant in question would be helpful. Also, seeds? Clones?

 

I cant give toy a 100% certain answer but I'd chalk it up to good genetics and growing it properly.
Some questions,
1. What is the soil your using
2. What nutrients are you using?
3. What kind of light are you using?
4. Are you low stress training?
5. Are you high stress training?
If you answered no to 4 or 5 --> 6. WHY?

 

Actually come to think of it I have a picture of one of my plants that I took when it was around 2-3 weeks old. It's about the same size as yours but it's a photofem not auto and I defoliate it often so it's not real bushy like yours.
The first and second photos are the same plant. the third photo, the 2 plants in the big pots in the front and back are the same age as each other, one of them is the plant from the first 2 photos, and the one in the middle is an auto

 

Your soil is alright, you might want to get nutrients as you need them, even if you need to go cheap you can always pick up some miracle gro. Your light is ok aswell.

EDIT the first picture in my last post on this thread you can see my lst with the wires

Ok so here's my crash course in low and high stress training.
To low stress train, grab a branch 2 inches from the tip and bend it downward until your leaves are vertical or less if your branch is weak and might break and use something to keep it bent, I use bendy wire but you can use twine aswell, make sure whatever you use to hold it is wrapped around the branch and only the branch, not on the nodes.

Hst is a little more tricky, you have to have a feel for it and you can only really learn through experience working with your plants, if you only have one plant I dont reccomend experimenting as you could easily fuck your plant over.
Personally I pinch a branch 3/4 of the way to the end of the branch with 2 fingers and then pinch about an inch below my where my fingers are with my other hand then, twist one set of fingers clockwise and the other counterclockwise and once I feel the fibers inside the plant tearing i gently snap the branch downward, then I move down the branch an inch and then twist my fingers the opposite directions (the fingers that previously turned clockwise will now turn counterclockwise and vice versa) and then gently snap up, then repeat until I'm at the stem. I do all my branches once a week and NEVER IN THE SAME SPOT.

 

If it hasn't started flowering yet your good to do whatever you want and even during the first week of flower too, the auto you saw in my picture was super cropped, a form of hst last week and is now tied down for some lst action and I'm not noticing any I'll affects

 

3 weeks for a comparison.

 

Leaves that aren't getting light are a waste of space, you should consider light defoliation, nothing crazy like mine but get rid of lower leaves that are just sucking up energy that could go to a bud site.

 

All it takes is a quick scroll of the forums to see you can barely compare one plants growth to another considering they're all different strains, different genetics, different soil, different lights/setups, etc.

Let YOUR plant dictate what is good or bad for your setup. One may water their plants every three days due to low humidity environment, another may only have to water once a week... some may supplement nutes, others go full organic, both of which have different effects on growth and the appearance of the plant.

As long as you're not seeing any deficiencies and the plant is still growing, youre doing fine.

I also didn't train my auto flower other than very low stress "ponytailing" in week 4.


Also, auto flowers grow very fast, especially during first 4-5 weeks.. so it's not unusual or unexpected for that 16 day plant you posted will be same as yours in one week.

For reference, 1st pic is at 16 days, 2nd pic is day 35

 

The day 35 pic is at end of that days light cycle, that's reasoning for slight drooping and is normal

 

And buy me a present please.