I think most people that want better crop yield, hq or a successful cross are just using G3 as it is. The only time I use the others now is for the flower pots or for the first seed in a fresh crop since it has nothing to cross with. Other than that the lower grades are fairly worthless. It's the G3 soil I'm hoping also get better yields simply because while it is on a timer, that's still 8 hours of waiting to gather a garden plot's worth without using retainers.