It is said that L-amino acids such as histidine, methionine, aspartic acid, glutamic acid, asparagine and glutamine can revert plant stomata closure, increase quality of fruits and assist maturity. It is also said that the best way to apply is through foliar feeding.

I would like to start experimenting with different amino acid foliar feeds but would first like to know if there is a recommended maximum/minimum/recomended Parts per million(PPM) , for foliar feeding of these compounds.


1 Answer 1


I know that some of the amino acids you listed are commonly found in fish fertilizer. I haven't read any studies on the use of these amino acids individually and not sure where you would purchase them separately. If you're just experimenting in your own garden I would just use fish fertilizer according to the label directions. If you look for fish fertilizer studies you'll probably find more info.

Also, I've never heard of these opening up the stomata of the plants. The only references I've read indicate that foliar sprays are best applied in the early morning or late day when the stomata is already open. This is how the nutrients get absorbed from the leaves.

I don't know that I would want to intentionally manipulate stomata closure. The plant knows when it needs to breath.

Where did you read the above info? I'd be interested in seeing it.

  • $\begingroup$ From my understanding stomata close when light and humidity are low, and temperature and salt concentration are high. When stomata close, photosynthesis and nutrient absorption slow and the plants respiration is increased. this slows plant growth and can affect end of year yield applying L-aminos favours the opening of stomata and increases plant health and growth in adverse conditions. Body builder shops stock individual l form aminos that are easily dissolved in water thus my ppm question. $\endgroup$
    – damien
    Sep 18, 2013 at 2:54
  • 1
    $\begingroup$ @damien I believe plant respiration decreases (not increases) when the stoma close since the stomata facilitate gas exchange. Transpiration also decreases when closed. If you're forcing the stomata open you'll need to water the plants more (or shade them?). See en.wikipedia.org/wiki/Guard_cell Still curious as to which sources you're referencing. $\endgroup$
    – OrganicLawnDIY
    Sep 18, 2013 at 14:43

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .