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Acid or alkaline?
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Posted by ifraser25 z11 Brazil (My Page) on Sat, Sep 27, 08 at 1:04
I have recently bought a number of plants from a local grower who produces very healthy-looking specimens. I noticed that he had added limestone chippings to the compost of many of his plants. When I asked him about this, he explained that when organic composts, bark etc, break down they become more acid. To combat this he added lime.
I had always been led to believe that with a handful of exceptions, most notably Paphiopedilum, the majority of orchids were lime-haters. Any comments? |
Follow-Up Postings:
RE: Acid or alkaline?
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- Posted by bolero VIC Aust z9 (My Page) on
Sat, Sep 27, 08 at 5:11
| My only comment is that any plant can only tolerate so much acidity so lime wouldn't be a bad idea for anything. If the mix dropped to an acidity of 5.0 then I would imagine it would need to be increased in some way. I am not sure if lime is the best answer but I have occasionally used it with no adverse side effects that I could detect. |
RE: Acid or alkaline?
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| I use limestone and granite interchangeably in my potting. Limestone doesn't dissolve very much except in the presence of acid, so I consider it more of a buffer than a base. Part of the equation is how much water is used in watering and the salt buildup of all kinds. If pots are flushed regularly, limestone is no problem at all. |
RE: Acid or alkaline?
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| It isn't so much that most orchids (and most paphs as well) are lime-haters it is that they prefer an acid condition. The lime is actually (should be) there to counteract an initially too acid situation. If the mix is presently neutral or only slightly acid the lime will pull it out of the acceptable zone right now and it will take a very long time before the slow creep towards a more acid condition makes the lime a useful item. Some organic peats and redwoods are very acid from go and adding lime in the mix is of benefit, not 'when' but 'right now'. So it really is a question of what exactly is the 'compost' made of? H |
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