Short answer: no, sugar is NOT plant food.

Plants do not take in sugar directly through the roots or through the leaves for that matter.

Plants take up chemicals, like nitrogen, phosphorus, magnesium and potassium (and water), through the roots and then the leaves perform photosynthesis using sunlight and carbon dioxide to make sugar energy (monosaccharides) in just the right amount they need.

Plants have no trouble growing well if all the right conditions and nutrients are given them.

Why would you want to do that? What are you trying to achieve?

Just curious.

-Babka

That question makes no sense. What do you think is a plants main energy source?

What do you think is a plant's main eneegy source?

I would say the sun.

^^^ And I would agree.

Indirectly there could be a benefit. You won't be feeding the plants for reasons others have mentioned but it will feed microbes in the ground and Plants can indirectly benefit from a population explosion of microorganisms breaking down organic matter the plants can then benefit from. But there is a catch.

Glucose is 40% carbon by weight. Carbon is the main food source for microorganisms and nitrogen is the 2nd food source requirement. The exact ratio is 24 parts carbon to 1 part nitrogen. If there is not enough nitrogen in the soil to feed the massive population explosion of microbes AND the plants also the little buggers will strip the soil of all the nitrogen and you'll end up with a nitrogen deficiency, and the plant will turn yellow and suffer.

So you will end up harming your plants if you do not add extra nitrogen for the microbes. But if there is plenty of nitrogen to go around it will benefit the plants because the microorganisms will continuously die and release all the other nutrients they consumed the plant can use. So what you also need to do it throw in extra junk high in nitrogen to also feed the bugs along with the sugar high in Carbon.

probably just attract bugs that crave sugar .. like ants .. etc.. [the point isnt that an ant may not be a bug...]

@k9408: ^__ Yeah, do it, what could go wrong? lol

Glucose is a minor product of photosynthesis, and it does have a role to play in a plants functions. There is science out there that explains it's multiple roles in plant development. This is a decent report that touches a lot of aspects: https://www.sciencedirect.com/science/article/abs/pii/S0008621519305142

Other sugars have roles to play as well. But the OP is asking glucose. Plants have it, use it- but differently than the way humans need/process it. It's not the energy unit to plants the way it is to humans.

There are labs checking into the use of glucose to enhance properties in plants, like this:

https://www.sciencedirect.com/science/article/abs/pii/S0304423812004517

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9099517/

Many folks know of the old florists trick of adding sugar to the water for cut flowers. Or soaking roots or cuttings in sweet water before potting up. And there are folks that make sugar ferment fertilizers that also can be used as foliar sprays. But those are more sucrose and not glucose treatments.

I too am curious about why the OP wants to do a glucose spray. What is going wrong that this may be a treatment... or in a healthy plant what the treatment is hoping to achieve.

@beesneeds im just trying to supplement a few potted deciduous plants with energy to recover from some serious slug damage on the previous flush of new growth. nearly all of the buds were eaten straight off. I moved the plants to a miuch drier concrete location away from the slugs. I was hoping that watering the plants with a diluted glucose or other sugar solution would provide the plant with the necessary energy to recover.

@sam_md the sunlight is used in the chemical reaction to create glucose, which is what is ultimately used for its growth and maintenance.

Skip the sugar dosing then. It's not going to speed up recovery the way I think you think it will. Just keep them correctly fed, water, and conditions correct for them to be happy. It's good you moved them to keep the slugs off. Let them just recover safely on their own.

I agree, most plants that are damaged will resprout new buds, especially this time of year (spring). Unless they've been through a few rounds of abuse already and are run down.

Keep them warm and be patient. Good things will happen. ;-)

We've had several threads about Magnolia scale. The complaint includes production of honeydew which attracts undesirable insects and sooty mold is also a problem. The same problem occurs with an explosion in aphid populations. "spraying sugar water" on foliage is a really bad idea.

The product of photosynthesis is glucose, which is a monosaccharide. The sugar we purchase in a bag is a polysaccharide, a more complex sugar that plants can't easily absorb or break down. Since anything in the soil solution that adds to the EC/TDS (electrical conductivity and total dissolved solids) of the soil solution can limit uptake of water and nutrients which are essential to normal growth, adding it to the soil solution is not a good strategy.

Sugar-water sprayed on foliage can clog stomata (openings in leaves which are regulated [opening/closing] by the plant) and the millions of intracellular pores in the leaf cuticle (skin). This would limit CO2 intake (limits photosynthesizing ability) and oxygen's escape from leaf tissues. The result would be less sugar (plant's energy source) available for metabolic processes and growth.