In the absence of high relative humidity (low air flow with too much moisture in the air) or heat stress (too much direct sunlight or too close to light), taco leaf is most often casued by a magnesium deficency. Use epsom salt, cal-mag, or bud candy to correct. Epsom salt is the cheapest of those three. Start with 1 tsp per gallon of water, apply twice. You can foliar spray, water it into the root zone, or both. If after two applications, things don't improve, increase to 2 tsp of epsom salt per gallon of water, but don't foliar, just water it into the root zone.