Carbohydrates in fertilizers.....?

[tucker85]

I read some old threads on Orchid Board that talked about using sugar, molasses or beer mixed with fertilizers. If these are beneficial (and that's a big "if") would it be the carbohydrates themselves helping the plant directly or by-products of the bacteria they support?

[gnathaniel]

Many plants can benefit directly from soaking up sugars provided to them. They use these in cellular respiration the same way they would sugars they make themselves through photosynthesis. I occasionally use weak sugar solutions to help rehab stressed plants that still have some roots available. This allows them to put on some growth without needing additional light (which can cause further stress) to photosynthesize.

One caveat, though, you may see an explosion of growth of opportunistic fungi or bacteria where the sugar is applied. Often these are sooty molds that don't harm the plant itself, but I think that more aggressive microorganisms may also increase in number from a sugary snack and then go on to consume parts of your plant. I usually either mix a small amount of physan in with the sugar water or else treat the whole plant with physan immediately after the sugar soak.

Hope this helps!

--Nat

[BobInBonita]

Never do it myself, but would expect a drop in pH from the fermentation that will take place. That COULD shift the microbial population towards yeasts and molds and inhibit SOME types of bacteria.

Let us know your experiences if you try it.

[Ray]

I expect that most of the molecules of some such complex carbs are too big for plants to absorb.

When applied to terrestrial plantings, soil microorganisms break them down pretty quickly, but it's doubtful they do much as-is.

[AHAB]

Hmmm
Any yeasts when provided sugars would produce c02 gas.
This might be enough to aid growth.
I've wondered if we should be feeding the mychorizal fungi which in turn would feed the plant as they go through their life cycles.