I haven't been here for a while - life is just way too crazy!
I just wanted to bring up the subject of the new understanding about calcium (and maybe add in sulphur)
I read somewhere recently it is now becoming considered as a major nutrient for all plants. I was just wondering if anyone has any input or knowledge about what the sources of calcium are for the South American cacti whose habitat is on non-basic rock, and how we should consider feeding them with new calcium-rich C&S fertilisers (like Growth Technology)? (And any input about sulphur would also be great!)
A long time ago I tried to find out what was in a number of different fertilisers - either by reading the contents list of packets I had or via the internet. The listed ingredients were often not complete, sometime just the basic N-P-K values with added micro-nutrients. At the time Phostrogen did give a comprehensive list and three of their products contained Sulphur and two also had some Calcium. No other product listed these elements. One of the products was their Tomato Plant Feed but I do not know if the current product has the same formulation
Even more confusing but ..... should you read the labels more carefully on the proprietary feeds you will see that the composition seems to be different for each of the UK, Ireland and the EU countries - but it isn't -- it's just the way in which the composition has to be stated for a particular state -- so some want the phosphorus component stated as the amount of phosphorus, some want it stated as the amount of phosphorus(V)oxide and some want it stated as phosphoric(V)acid.
As stated above, the amount of calcium in tap water will probably be more than adequate. Soil/compost is a dynamic system and the plants will take what they require.
AND do you mean sulphur? or do you mean sulphate(VI) or sulphur(IV)oxide or sulphide? All these could be present in your compost -- or rain water --- or feedstock ---- and are needed in such small amounts by the plants --- and in different amounts by different species.
Endeavouring to grow Aylostera, Echinocereus, Echinopsis, Gymnocalycium, Matucana, Rebutia, and Sulcorebutia. Fallen out of love with Lithops and aggravated by Aeoniums.
Currently being wooed by Haworthia, attempting hybridisation, and enticed by Mesembs.
Gerald - I don't use tap water on any of my plants. I only use rainwater collected in water butts from roof run-off. There is a very clever chap who grows orchids on YouTube who has a a history in hydroponics, who says that calcium in the form of carbonate is difficult for plants to absorb anyway....
There are a few sources saying calcium is a major nutrient, I just Googled "calcium major nutrient for plants" and a few pop up...
And some say sulphur is a major one, some say it is a minor one... El48tel, I just mean the sulphur ion
Karsty ... don't wish to be pedantic .... but .... which one? There are many ... and will have so different effects on the plants. I'm no horticulture expert but would say a quality growing medium and a quality cactus feed in the stipulated dilution would be more than adequate.
Endeavouring to grow Aylostera, Echinocereus, Echinopsis, Gymnocalycium, Matucana, Rebutia, and Sulcorebutia. Fallen out of love with Lithops and aggravated by Aeoniums.
Currently being wooed by Haworthia, attempting hybridisation, and enticed by Mesembs.
Sorry, but a bit of chemistry is needed. Sulphur does not normally exist as an anion S(2-) although dissolving hydrogen sulphide in water does generate the smelly hydrosuphide ion HS(-) of no interest to horticulturalists. The anions that we are interested in are composed of sulphur and oxygen of which the commonest in the sulphate anion S04 (2-) and there will be plenty of this floating around in most feeds usually from potassium sulphate.
Calcium cations Ca (2+) will be generated to a greater and lesser extend by dissolving calcium salts in water. Since the solubility of calcium carbonate is fairly low, the amount of calcium cations in the water will be below. If you wanted higher concentrations then salts such a calcium nitrate, which are more soluble in water will give greater amounts of calcium cations.
The bottom line is just use something like Chempak 8 to feed your plants and forget the chemistry!
Sorry about my inability to generate subscripts and superscripts.
