Couldn't agree more. Mine are for personal use as well! Don't think I could part with em unless it was in smoke
While MJ is a sun loving plant hps can be a bit intense for babies the size of yours. When my grass was still young, about the age of yours, I kept my 400w HPS about 35 inches away from them. It wasn't until vegetative stage (when in nature it would be switching from early spring to late spring/summer) that I brought my light down to about 16-18 inches and added ventilation to account for the extra heat.
Also, you've mentioned a lot about nutrient issues and PH problems. In this early stage of life nutrients are not so important as you might think. Your plant will not begin to consume nitrogen
en mass until it reaches vegetative stage. I had great success with plain mildly fertilized potting soil, and didn't receive any bat guano until they were about 16 inches tall. about as soon as they Also, high PH will lock out a lot of nutrients including nitrogen so it's very possible that your plants will begin to show improved colour and health after some routine PHing. A lot of people wait until the plant has produced its first 5 pointed leaf and entered the vegetative stage of growth to begin adding nutrients at their recommended dosages. Your vegetable compost (I'm assuming is some you've produced on your own) will probably have plenty of nutrients to at least get your plant to veg stage, at which point you'll notice it will become a glutton.
AAAAAnd another thing; I read somewhere along the line that you were feeling the need to mist soil between the 3-5 day spaced waterings. In my experience small 4" pots dry out so fast they can require watering as often as once a day under an HPS light. It may not feel like it to the human hand but HPS lights put out a remarkable amount of energy that while maybe not fully accessible to a human hand is as plain as day to a plant leaf. The more a plant leaf consumes in light energy (resulting in accelerated photosynthesis) the more it perspires and in turn the more water it consumes through the roots and leaves. This drying effect is further accelerated by the simple heat produced by the light itself. Also, moving air can greatly accelerate the perspiration process.
My recommendation is invest in a cheap moisture meter at your local store, water as soon as it's dry, never go beyond moist, and your plants will always have the perfect balance of moisture/oxygen in their soil, especially with the vermiculite and perlite you've provided them.
Cheers, please feel free to ask any questions if you have them.