Question 1: Is the fertilizer I use the problem fo...

Hi shortcut.... to young to much nutes..... Longer version, your seedlings dont need a feeding before the 4th node appears( around week 3 and 4) your soil provides enough food until then. Your fertiliser has to high percents of everything its meant for the final strech in 2nd or 3rd week of flowering. Put it away and buy another with around 4- percent N... and then start with 25 percent of the recommend amount. more to read in the comments. Be blessed and happy growing

Although not related to the question, I strongly advice you to use screw in LED bulbs, they are much better than CFL, you get the same result at 25% the power (or 4 times the yield at the same power). Check my diaries if you are curious about them. Now for your question, 11 liters of soil should have enough nutrients for 7 to 8 weeks before needing aditional feeding. You are just feeding too early. Also you should get an EC/PPM meter (and ph meter), it really helps in feeding the right amount. For now stop all feeding and just give plain water, only resume feeding if you spot a deficiency.

I would say yes , that's quite the mix you have in NPK value for such young seedling . I would firstly reduce the strength of the nutrient solution to 1/4 strength until the plant starts to grow . I would aslo suggest that because your growing medium is soil that you only feed with nutrients every 2nd or 3rd feeding . Soils tends to retain a lot of the nutrients and the plant cant absorb all of it at once . So in between nutrient feeding i would feed it PH corrected water . You also don't wanna over feed your plants soil usually takes a bit longer to dry I would only water if the top of the soil is dry as a bone 1.5 inches deep into the medium .I might also suggest you lower your PH slowly to 6.8 so you don't get any nutrient lock outs so your plant can absorb every nutrient it can . Remember that less is more when they are young like this . So all in all you have a slight few things to adjust here and you will be rocking and rolling ! I hope this information helps you on your journey ! -Happy Growing!