Sugar in water

I read somewhere that putting some sugar in the water makes some plants grow better. Can orchids absorb sugar from their roots? Any experiences? Thanks!

I've only heard of it to keep blooms in water alive longer.

Some organic people swear by adding molasses to their ferts. and fermented fertilizers are made with sugar but I think that's converted to organic acids?

I would be concerned that it would attract ants.

If you do, you can get better growing, but it is not a must. Adding LOW amounts of sugar to water - those owning an aquarium know it if they ever tried to lower the pH with vinegar! - will increase the bacterial/fungal flora inmediately. If this happens in the substrate, you have a short increase in mineralization - all is speeded up - which can be helpful as long as the roots are not affected.
Be careful, because al rot-pathogens will be boosted, too. And there will be a O2 shortage, too.
If you have a compost or a kind of bokashi all sugars increase fermentation, but will be gone by the time the fermentation ends and the fertilizers are used.
I wouldn't use it - though it is sometime recommended for epiphytes without roots (bag method) - because once you start the bacterial boost, you cannot control it any more until the effect ends.

Not long ago in a large order of small cattleyas I 'lost' one in the packing and didn't find it for three/four months - I was cleaning up my 'might need' boxes for trash when I discovered the little guy. Fortunately, I had gone over an old orchid book that winter and in it it had a chapter on imported orchids and how to revive them. I figured, what could be the difference between this guy and those they remove from nature, pack in crates, and ship several months till destination. The book said to soak in sugar water and that is what I did to this dehydrated orchid. The next day I planted in sphagnum and a year later it looked like a normal robust growing seedling in its 2 1/2 inch pot. I was thrilled. But, I only did an overnight soak. I also feel that it would not have survived without it. I think some immediate absorption must take place. This little guy looked good in under a weeks time and recovered far faster than any I have ever tried to save from less rigorous conditions.

Since the whole point of photosynthesis is to produce sugar I don't think there is a direct consumption of sugar by plants to increase growth (unless the plant is one of those non photosynthetic/parasitic species).

Often orchids exude sugars out of their roots, and I'm sure they can uptake them through roots too.

Adding sugar to potting mix is most likely feeding the fungi and bacteria in the pot, which will change the environment around the roots. This could produce simple things like CO2, or much more complex things like antibiotics, that the plants would likely uptake.

Plants also seem to uptake amino acids directly which bypasses the steps need to convert nitrate to ammonia, or ammonia to amino acids.

Feeding the sugar to the potting mix may get all the nitrogen fixers and heterotrophs to produce a bunch of amino acid for plant uptake.

And then water/osmotic balance may be the prime action (suggested by Bullsie)

You could probably get all the benefits of sugar more directly from addition of a kelp extract. Its full of amino acids, and lots of other organic materials.

I've used sugar & water for decades after deflasking plants of all genera. They respond better & establish much quicker than using anything else. I use it for the first 3 months then reduce it when the new roots start off.

Roy said:

I've used sugar & water for decades after deflasking plants of all genera. They respond better & establish much quicker than using anything else. I use it for the first 3 months then reduce it when the new roots start off.

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What is your procedure Roy?

Same as Mike, Roy we listen to you.

btw, here some recover dehydrated orchids not with sugared water but with honeyed water. Honey is even better as it's not only some carbohydrates.

When I saw the papers, I was surprised that plants can absorb amino acid and sugar via root. According to a paper, sucrose (which is the basic transport sugar in plants) is more easily absorbed by plants than glucose. Isn't honey more of monosaccharides (glucose and fructose)?

Given that the whole point of being photosynthetic is to produce sugar, does it argue that a plant in need of sugar is in trouble to start with?

Well, if we consider that carbohydrates are like currency for plants (short term storage of energy in chemical form), don't you be happy to get extra income like winning lottery (even if you are NOT broke)? But I don't know if added sugar helps plant in reality; my quick search in scientific papers didn't show something which says that added sugar will help the growth of plants.

As you mentioned, roots excrete and absorb carbohydrates to control nutrient uptake and rhizosphere environment. I thought that it is an interesting aspect of plant nutrients.

naoki said:

Well, if we consider that carbohydrates are like currency for plants (short term storage of energy in chemical form), don't you be happy to get extra income like winning lottery (even if you are NOT broke)?

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That is a funny analogy to consider. :rollhappy:
But I'm not sure if biochemical functionality is as flexible as behavior. What happens to humans as you increase sugar? Diabetes, obesity, spleen and pancreas dysfunction... and we don't even make our own.

A little bit (and I'm talking single digit ppms) may seem like a windfall to a photosynthetic organism, and may elicit "happiness" in the plant. Maybe it will take a vacation and go on cruses during cloudy days. Along those lines, maybe sugar uptake is a means of coping with low light levels or short day lengths.

I'm just suggesting that if the plant is "calling" for sugar, something is impaired in its ability to make its own.

Stone said:

What is your procedure Roy?

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Reasonably simple. I dissolve 5 teaspoons of white sugar in a litre of water & pour it on just enough to wet the potting mix. I do this every time I water the plant or compot. After 3 months, give or take a month & growing conditions I reduce the sugar & replace it with very weak normal fert'. I use this for another month then remove the sugar but maintain the fert' ratio. By this time the roots should be very well established & plant stable.
One thing I've learnt the hard way is to use normal fert' too early. The plants have to develop 'new' roots as the ones they have are conditioned to grow in the flask media, not potting mix. They are basically growing in pure food & don't have to find it.

Would the same result be obtained with an organic fish/seaweed fertilizer without the accompanying ant infestation?

Some have success with it but the same principles apply. Fish/seaweed fert's work ok on established root systems that are adapted to compost or soil, ie, trees/shrubs etc. They start off in a solid media, orchids don't.

In France, some use honey in water to bathe a few hours dehydrated plants.

I have too many problems with ants in my greenhouse as it is, so I would be hesitant to introduce a draw-card which would cause every ant for miles around to pack their bags and catch the first transport to candy heaven!

Ants are always around, I don't believe the sugar water attracts them. Its the sap from plants that attacts Aphids & other insects & the ants come after them for food. Ants will bite buds & growths to draw sap & attract the insects also. Thats why many growers find little pimples on flower buds.