Trying to Maximize Yield per Cost #1

Starting my first proper grow. Set up cost (fixed costs) -Lamp: 40€ -Timer: 3,5€ -Pot: 4€ -Total fixed costs: 47,5€ Given 5 years (or 15 grows) usage time translates to around 3,17€ per grow in materials. Variable costs: -Seed: 5€ -Soil: 6€ -Fertilizer: 3,50€ -Power (100 days 20h/day): ~28,8€ (exact figure after harvest) -Total variable costs: ~43,3€ -Total costs per grow: ~46,47€ What I've learned from my first two grows: -Bigger Pot -Very litle water in the first weeks -Topping the plant to prevent the main branch towering over the others / better canopy management The soil is All-Mix with a few hands full of Light-Mix around the seedling. PH is adjusted with vinegar and the tap water information for my zip code No fertilizer until flower I am very happy with the performance of the 36W LED so its gonna be by my side for a long time to come.