For example, I have a lot of plants inside (African violet, geranium, coleus, etc.) and outside (dolichos, petunia, pansy, asters, etc.) my home. Also, I have a lot of chemicals (such as ammonium nitrate, magnesium sulfate, ammonium molybdate, etc.) that can be used to compounding or correction of fertilizers. But I found only individual science research for geranium or petunia (for example). Is there a directory of precise dosages of fertilizers for indoor/outdoor plants?

1 Answer 1


No, I'm afraid not. Because plants vary in their requirements in terms of fertilising, it's more usual to start with the plant you want to feed and check what it requires in case it's anything particular (orchids, for instance, have specialist feeds available). At a very simplistic level, feeding also differs depending on the results you want - for instance, you mention Coleus, which is usually grown for its decorative leaves and not for its flowers, which would mean a fertiliser with a higher N level than K is more appropriate, whereas a plant grown for its flowers might do flower better with a different formulation. I'm not sure how you'd source the full readout of NPK plus trace elements required for every plant, nor do I believe any such resource exists for all flora.

Because it's quite a complicated area, proprietary brands of different feeds are available, ready mixed, with or without trace elements, because unless you're a chemist as well as a horticulturalist, working out precisely which chemicals to mix for different plants would be extremely difficult. I imagine its possible you have some sort of chemistry background though, if you already have the chemicals you mention available.

  • @AleksandrVishnyakov - well hopefully I understood your question - the real question, though, is did you understand my answer? Oh dear, your comment has now disappeared, rendering this response irrelevant...
    – Bamboo
    Mar 2, 2015 at 13:27
  • I apologize for my English. Of course, plants has a different requirements in different places, growing habitat and result. But any plant has a specific requirements and optimal values. For example, streptocarpus need ammonium nitrogen, instead of nitrates like many other plants. Coleus (here you're wrong) need a high dose of K, if you want to get colorful leaves (I use NPK 2:1:4) and less P to prevent flowering (but it need high N and P at start). I just think, that scientists, who grows plants for experiments/in vitro, has a something like databse with optimal values for macro/micronutrients Mar 2, 2015 at 13:37
  • I just press Enter too early ;) Mar 2, 2015 at 13:53
  • @AleksandrVishnyakov - I meant less K in relation to N re Coleus, but never mind. There may be resources for some plants (you've found some already) but it won't be for all flora. If you find that kind of 'bible' I'd be interested to hear about it.
    – Bamboo
    Mar 2, 2015 at 14:06

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