Lettuce or outdoor green stuff for N foliar

I did some thread searching through Google rollitup and have had experience cultivating. so right now I have some baby seeds 2 week's old tomorrow under a dimmed blue light to 250 watt, 3-5 inches from the glass. Timer fan to help keep the temperature lowered on fixture and the bulb. Mylar for the walls on it's way. As they grow they will get thinned out and adjustments made for maximum lighting, heat, ect. My current mediums are.

Root Organic 707 soil
Some rooting liquid
Plant Success granular mycorrhizae 3 - 1 - 3
Growmore seaweed extract .1 - 0 - .44
Iguana juice 3 - 1 - 3
Earth Juice Oily Cann (Ca) 3 - (Mg) 1
Mendocino Honey .46 - .26 - 1.86

So far my babies are off to an okay start. 24/ 12 Led 12 natural lighting, and a night under 250watt 3rd set of true leaves are looking neat, 2nd set of leaves 1/3 bigger than the 1st by a couple days, some yesterday. The biggest stems above birth leaves are a nickel and a few papers thick. They have been getting some intense lighting, but they are lacking N.

So they lack N and the 707 is a heavy water retaining soil. Causing a over watering sign in 1 of the bigger babies, and the lack of ability to grow fast and fat. I was thinking I could use 2 ml dosage of Iguana juice that is recommended for 3-4 sets of leaves at the next watering, if my soil didn't retain so much water, and they didn't need a day or a few for there next watering. There is nothing I have for foliar spray that could fix this, maybe if IJ was foliar.

So what to do besides buy some N. If I had lettuce could I wash that off, make a neat mess of it, put it through a coffee filter, and foliar spray that N up on there? There's some dark plants outside I could get at too. Any thoughts? I used to wash lettuce off at a deli and I brought a lot of life to there Hawaiin themed plants around feeding them that green tinted water. I don't think it could hurt right?

Look, you are going to kill your plants if you go on like this.
Give em some time to sort out shit for themselves and toughen up.

My favourite source of N is to wash out my aquarium filters in a bucket of water.

Well if they show a lack of N, even after explosive growth and roots showing through a cup and a half of soil, the next watering could use a full dose of recommended 2ml/liter for (3-4) sets of leaves of the iguana juice 3 - 1 - 3 and I shouldn't be too worried about nutrients burn, as long as I continue with the equivalent growing environment.