I would love too see a plant that was only foliar fed out perform a plant fed naturally via its roots. Not on here to fight or argue just making a simple easy observation based on science and natural order. Plants take in nutrients from their roots and use the leaves to transpire. If you foliar spray your plants constantly you are just asking for issues unless it is a product or supp/add that is made specifically for foliar applications. I use kelp and bene/microbe product including fulvic acids. The only time other than this is the odd time Im observing a nutrient deficiency primarily mag in which I will root drench and also foliar spray for maybe 1-2 light applications. You never want to exceed 350 PPM thru a foliar application, otherwise you are asking for big problems. I have never heard of any grower just foliar feeding their plants and barely any root drench feedings that have good results, it just isnt how it works. I know plenty of growers who foliar app certain things like mag/sulphur and fuvic/humic and benes etc that serve specific purposes but never just foliar spraying for feeding their gardens that just doesnt make sense to me at all.. Your roots are what is important and will take care of everything and as long as you feed and have good ph and good rhizesphere parameters than foliar feeding should be minimal and specific in its intent.opinions about foliar feeding from folks who have never done it and who appear to have little knowledge and understanding of research and agricultural practices isnt really very satisfactory.
foliar is well reseached and widely practiced in agriculture and cannaculture. plant nutrition can be tweeked on the fly, plant defenses enhanced, stress mitigated , reproductive response heightened etc. stating that plants should get their nutrition only through their roots or that leaves are for only transpiration completely ignores a scientifically validated and common agricultural practice. @steverthebeaver81 over on 420,there are a group of high brix growers. they foliar their plants start to finish. the results are consistently superb