If I were looking at the same problem as you, I'd focus on supplementing the phyllosphere via foliar applications. I'd use coconut water/aloe (both fresh, because they're available to me right outside) perhaps everyday if possible, if not at least 3-4 times a week. Adding kelp, potassium silicate, fulvic/humic acid, ACT, FPE etc. (in moderation, of course) will only add to the benefit and make nutrients available via leaf surface. Cultivating indigenous microorganisms and applying them to both the phyllosphere and rhizosphere (and soil) will "boost" growth and not only inoculate what it comes into contact with, but will help to serve against pests and disease. I'd follow up with as much compost as you can fit on your soil, watered in with the same kind of foliars you may be messing around with that day (just to make life easier...). I'd also look into a supply of micronutrients, perhaps rock dusts or something, because when micronutrients are in low availability or depleted, other nutrients become tied up or inhibited. I suppose that can go for any nutrient, but anyhow...
I have a lot of friends who ask about what they should do to improve their veggie gardens, indoor gardens, etc. and although I am by absolutely no means an authoritative figure on the subject matter, my first piece of advice is to start composting and taking care of the worm population (or better yet raising them yourself).
Organic matter also helps as a pH buffer... I personally have never had to pH anything. Most "organic heads" gave a chuckle and offered an inside joke when I used to mention pH meters...
Sorry for the novel, hope it helps. Enjoyed the last grow, keep it up!