However some people are complaining that it's difficult to mix and a few people complained it killed their plants, although they assured that they had mixed it properly and sprayed in early morning.

Any experiences or thoughts to share? Or any ideas why it would kill some people's plants and not others?

In most cases there is no reason a plant won't get ample micronutrients via it's roots.

While there does seem to be a trend toward foliar sprays these days it really doesn't make any sense to me outside specialist applications.

I would recommend spending the money on a complete fertilizer containing all the major, secondary and minor nutrients such as Foliage Pro 9-3-6 instead.

GMAB! ;o)

Generally, the only time foliar nutrient sprays are used in agriculture are during periods of exceptionally rapid growth when Fe, Mn, or sometimes Cu are deficient or borderline deficient in soils. This product makes all kinds of claims (like Superthrive and Eleanor's concoction) that would be extremely difficult to substantiate.

From a recent post: Some plants can absorb nutrients through foliage and sometimes stem tissue in ionic form, but the larger organic molecules of 'organic' formulas are unable to permeate cell walls. Water & its accompanying solutes are sometimes transported through the cuticle or epidermal cells of some leaves & twigs by diffusion, where it is adsorbed on the surface of plasmalemma (a kind of protoplasm that forms cell walls) where, by osmosis, it passes through cell membranes to cytoplasm. In some plants, water is taken in through open stomata as a secondary pathway. How much water can be absorbed through leaf & twig tissues varies by species, & within species, cultural conditions also have great influence on the process. Ambient temperature, relative humidity, leaf senescence (age), light intensity, nutritional status of the plant, time of day, all have impact on how readily water is taken in through leaves & twigs. Using a surfactant (wetting agent) also facilitates diffusion. The primary factor creating a barrier to diffusion through leaf cuticle tissues is the amount of (epi)cuticular wax present in epidermal tissues.

In agronomic applications, generally only Fe, Mn, and sometimes Cu are applied as foliar nutritional sprays because the pathway via foliar application is often more efficient than the 'soil to roots' route. Note that these elements are in ionic solution when applied.

Soluble salts present in foliar applications may or may not be available, depending on the plant, but the larger molecules are not - unless they are broken down by micro-organisms on the leaf surface (unlikely and inefficient if it was occurring) and diffuse into tissues via the same pathway(s) as the already soluble minerals.

Based on the link you provided and what I know of physiology - I would save my money and buy a fertilizer that contained all the essential elements, or use a soil micro-nutrient supplement.

Another thing: When you apply immobile micro-nutrients via foliar applications, the nutrients remain in the leaf they contact (because they are not mobile in the plant). This is a temporary fix, if the plant can access the nutrients, but it does nothing to fix the problem in newly emerging growth. Ca and all the micro-nutrients must be continually present in the nutrient stream to prevent deficiencies, and the only practical way to achieve that it is to have it available via roots.

Al