Removing Scale build up on pots?

[shanemartin]

Anyone know of a non caustic cleaner for removing this white scale type build up on some of my pots. No amount of scrubbing with soapy water will budge the stuff.
We are on bore water and have since heavily filtered our waterlines, and no longer get the problem, however it's the pots "pre filtration" that need the once over.
thanks

[NBPCA]

Try White Vinegar and a tooth brush or something harder but not too abrasive.

Start at 50/50 and see how it goes.

Grant

[Pup]

Good old WD40 with some repeats it does work with most.

Also Tonizone furniture polish this is an Australian furniture polish with lemon and no silicone, again some repeats may be necessary.

I have found both work Tonizone as a far better aroma too.

Cheers a very clean Pup

[shanemartin]

I'll give both suggestions a go..... my wife informs me that the scaley build up was from a granulated slow release fertilizer high in nitrogen, that we used to use a while back. We now only use chook poo and seaweed solutions, and our trees and pots have never looked better.
Thanks for the help

[Jan]

Bi-carb Soda works a treat; just use a damp cloth, dip part of it into the Bi-carb and use it like any abrasive cleaner. The difference is that Bi-carb doesn't scratch, but is abrasive enough to give the pots a good clean.

Works a treat on other surfaces that you want cleaned withour scratching, too.

Jan

[Jester]

Try using Crean mate (That stuff from Japan that you buy from bonsai nurseries to clean your blades) I had read somewhere that it could also be used for pots and I tried it. Fantastic!!!. This is by far the best tool I have for bonsai related work. After this, in order to shine the glaze on the pot, I used a Lanolin based lubicant which comes as a spray called Lanotec. You can purchase this at Supercheap auto.

I think you will get excellent results with this combination mate

John

PS The suggestion above is only for glazed pots

[wrcmad]

I thought I'd bump this thread after some success with removing scale from a pot this week end.
I have a chemical back ground, and thought some extra info may be useful.

Recently, I acquired a scale-covered Tokoname pot VERY cheaply from Japan. Nobody wanted this pot due to the ugly scale coating, but I knew there was a gem of a pot to be had quite easily.

Anyone know of a non caustic cleaner for removing this white scale type build up on some of my pots. No amount of scrubbing with soapy water will budge the stuff.
We are on bore water and have since heavily filtered our waterlines, and no longer get the problem, however it's the pots "pre filtration" that need the once over.
thanks

Scale coatings are usually the result of watering trees with hard water - water containing bicarbonate minerals (calcium bicarbonate and magnesium bicarbonate). When dissolved, these minerals yield calcium and magnesium cations (Ca2+, Mg2+) and carbonate and bicarbonate anions (CO32−, HCO3−). Frequent wetting of pots with hard water will leave a thin scale layer of these bicarbonates on the pot when the water dries. Over time, multiple layers are laid down to form an ugly thick layer of scale.

Fortunately, this bicarbonate scale dissolves easily in acid, and requires only a weak acid to dissolve. The cheapest, easily accessible and safe acid for removal of this type of scale is acetic acid (vinegar).

Here is the one I cleaned this week end:

Take one scale-coated pot:

Scale1.jpg

And a few bottles of cheap-ass vinegar:

vinegar.jpg

Soak for a couple of days, remove pot, rinse and wipe off. Presto!:

Scale2.jpg

However, there may be other scales present that need different treatments:

..... my wife informs me that the scaley build up was from a granulated slow release fertilizer high in nitrogen, that we used to use a while back. We now only use chook poo and seaweed solutions, and our trees and pots have never looked better.

The clue to what may be happening here is the use of "granulated slow release fertilizer high in nitrogen", combined with the use of bore water.

Firstly, bore water will usually contain a certain amount of the above-mentioned calcium and magnesium carbonates. Because they are dissolved in the water in ionic (dissolved) form, filtering will not remove them.

Secondly, slow-release, or controlled-release fertilisers (the distinction of which are mostly but a mere marketing ploy for reasons beyond the scope of this discussion) are fertilisers that releases nutrients gradually into the soil.
Conventional fertilisers are soluble in water, meaning the nutrients can disperse quickly as the fertiliser dissolves in water, and wash away before the plant has a chance to uptake the nutrients.
Slow- or controlled-release fertilizer is a fertiliser containing a plant nutrient in a form which delays its availability for plant uptake and use after application. There are 2 common methods of achieving the delayed release of fertiliser materials in retail fertilisers:
1. Fertilisers in which a physical barrier controls the release - controlled water solubility of the fertiliser material by semi-permeable (often polymer) coatings - eg Osmocote.
2. Fertilisers in which an inorganic low-solubility chemical barrier controls the release - hi-nitrogen granules commonly have an insoluble substrate of sulphur or sulphur-compounds that restricts the dissolution of the fertiliser material.

If it was the case that the fertiliser being used was sulphur-coated, and being used in combination with bore water containing calcium ions, then it is possible that a calcium sulphate (plaster of paris, gypsum) scale was being formed on your pots. In this case, unfortunately, vinegar will not dissolve the calcium sulphate scale.
Instead, the calcium sulphate needs to be converted to calcium carbonate using sodium carbonate (soda ash, dissolved and used to soak the scaled-pot in). Once converted, the calcium carbonate can be dissolved with vinegar. However, this calcium sulphate conversion to calcium carbonate usually takes place as a surface reaction, so may need to be repeated a few times followed by a vinegar treatment before fully removing the scale layer.

Hope this helps.

Regards

[Watto]

Thanks WRC, that was very informative.

[delisea]

This is the best non-tree post of the year. It is off the point, but this why everyone should learn some science.
Cheers,Symon

[Rolf]

Recently, I acquired a scale-covered Tokoname pot VERY cheaply from Japan. Nobody wanted this pot due to the ugly scale coating, but I knew there was a gem of a pot to be had quite easily.

BTW really nice Pot!!!!!!!