Need help: Interveinal chlorosis & weird growth at base of the stem

Hi there! Help!
 
It's my first time growing pepper plants, but not the first time growing things indoors. My two young pepper plants are not doing well. They both suffer from the same afflictions, but each at different degrees. I need some help to fix them up before they die, or worst, infect my other plants with the same afflictions.
 
They are in peat and perlite with a small amount of dolomite lime. The peat has been through a light flush before being used. I started to feed them after the development of true leaves. I use an organic fertilizer (BioCanna Vega) and gave them the lower end of the recommended dose, always with some run-off. I wait until the pots are fairly dry before watering and I did not always feed (maybe I should have...). This combination normally works well with other kind of plant I grow. You can see some healthy catnip in one of the attached picture (ok, it's in coco coir but it's just to show I have some basic growing skills...)
 
They had a serious case of purpling. I believe this has been mostly fixed when I started to put a small amount of magnesium sulfate in the feeding water.
 
Growth seems slow in comparison to my other plants.
 
They got interveinal chlorosis. It started real early (on the first true set of leaves for both plants) and went on. Looks like nitrogen and/or magnesium deficiencies but my other species never had this problem at this young age. They received pretty much the same conditions and treatment. I must say that the chlorosis condition has improved since the last watering (it was really serious), but it's still definitely there.
 
Also, they have some weird growth that looks like root shooting out at the base of their stem (see 2nd picture, no it's not perlite stuck on the stem). Maybe it's nothing to worry about for peppers, but I can't tell.
 

 

magnesium deficiency probably.
 
you need like 2 grams per gallon minimum up to like 4 grams per gallon.(50 mg/l to 100 mg/l). any more is a waste and potentially harmful. 
the root nubs are normal. some peppers do it like crazy, others do not.
 
its called adventitious roots or something like that. they respond to high humidity environments. my melon root stocks do it like crazy.

Soil might be too wet.

Overwatering for sure, the soil looks saturated.

What's the nutrient profile of your fertilizer?

Oh, and welcome to the forum!

This is my first year growing peppers as well, however, like you, I have grown many different types of plants, indoors and out. You will learn real quick, with pepper plants, not to over water them, because they will respond, negatively. You should let your soil get dry throughout before watering. Look at your plants for signs of wilting before you water. How old are your pepper plants, and what type of lights are you using?

Thanks for all the replies!
 
About watering, I always wait until the pot is dry before watering. The pot becomes at least 2x heavier when I water because I saturate the medium. What is on the picture is the pot less than a day after watering. Aren't overwatered plants more droopy than mine? However, maybe my mix doesn't drain enough. I'll put more perlite when I'll transplant, it should help according to the replies.
 
The profile of my fertilizer is 3.5N-1.0P-5.5K , with 2.6N being "water insoluble organic nitrogen" as per the label.
 
Germination occurred around 2016-02-09 for both but the stretched one was put into potting mix 2-3days after the stockier one.
 
I use a 45w CFL with a cheap bowl shaped aluminium reflector. The bulb is about 4in above the pepper plants.

45watts of light for the space that you appear to be using seems a bit low. Furthermore, fluorescent lighting doesn't really provide all the wavelengths of light in the natural light spectrum that some plants require to be able to grow healthy. As a result, you may have the proper nutrients in your soil, but the plants just can't use them if the lighting isn't adequate. Most people who have their pepper plants under fluorescents, eventually transfer them to a different light source, usually natural light. Maybe someone who has had success using fluorescents for growing pepper plants from seedlings to flowering, can provide more information in regards to how much wattage per square foot they require, and other details. If you plan on keeping your pepper plants under artificial lighting permanently, I would recommend that you upgrade your lighting. I have had great success using metal halides and high pressure sodium HID lights together.. The wattage necessary will depend mainly on the square footage of your grow space and how much wattage per sq foot pepper plants require. Metal halides provide a high amount of blue light necessary for vegetative growth, and HPS lights provide more of the red light necessary for flowering.

As far as watering is concerned, just because you are waiting until the soil gets dry before you water, doesn't mean that you are not over watering when you do water. Based on the looks of your pots and how much time has gone by since you watered, I believe you are over watering them (when you do water.) Cut back on the water for sure, maybe half as much or less than half as much. Make sure that you are aware of the moisture content of your pots. Don't retain water with containers on the bottom of your pots to catch the excess water. If you do, dump them when they fill. I would install a small fan and make sure that you have some ventilation going on as well.

It looks like your medium is holding on to too much moisture.  If you can, you should re-pot into a better mix.  Your other plant is in coco coir - if you have some left you could try equal parts peat, coco & perlite with a pinch of dolomitic lime.
 
Wait until your soil is very dry (i.e. until the pot is very light) then bottom water with your nutrient solution (at whatever the manufacturers suggested rate is), only giving them about an ounce of solution at first.
 
The NPK ratio of your fertilizer seems fine, does it also contain calcium, magnesium & other trace minerals?  If not, pick up some cal-mag too.

over watering again eh?
 
pro tip. its never over watering if the plant is turgid.
 
if its over watering the plant will be wilting from damage to roots caused by bacteria or fungus.

overwatering damages by fostering growth of microbes and excluding oxygen.
 
if you have anything close to a light airy mix, this is very difficult to do. if you have a very heavy mix with lots of organics it is quite possible.