Green algae powder.

[Vimto]

Can anyone tell me where I can obtain green algae powder at modest cost. It is to make up a formula for promoting lichen growth on outside stonework. All the stuff I have fiund has been from herbal or health food suppliers who charge a zillion pounds a thimble full. I only need about an ounce.

[heathfield]

Why not try yoghurt? It's commonly used to give plant pots an aged appearance.

[EcclesCake]

A friend of mine painted her patio extension with yogurt, it seemed to work.

[Ratty2E]

A mixture of live yoghurt and horse manure is supposed to work well to age outdoor stonework too

[Vimto]

Yes, I agree, yoghurt is fine to produce ageing and mosses but my aim is to grow lichens which yoghurt, whilst doing no harm, does not do anything positive to promote. In fact, if moss does grow well, it does not leave room for lichens.
Lichens are a symbiotic organism of fungus and alga growing together and can frequently be seen on old stonework such as gravestones and also on old trees. They are a sign of pure air as they do not tolerate polutants.

[jomifl]

I'm not sure how green algae is going to become lichen. If the atmospheric pollution is low it will arrive under it's own steam. If you want to speed things up you might be better off just macerating some lichen in a blender and painting it onto your stonework. If you cannot get hold of any I can send you lots.

[Vimto]

Ah, hello jomifl, somebody with a bit of prior knowledge. I wish to encourage lichen growth on a recently purchased birdbath which is made from faux stone. I googled "how to grow lichen" and have now a recipe for a Macbethian brew made from milk, flour, yeast, plain gelatin, green algae powder, a pinch of feriliser and crushed lichen. I have all the goodies except the algae so asked here if anyone knew a source. Thanks for the offer of the lichen but after visiting my local graveyard I have a plethora of different samples which I can use in my brew so it's now a case of "double, double, toil and trouble" for me but still need the algae to make the spell complete!

[heathfield]

Scrape some off a wall? Plenty round my way!

[jomifl]

If you have got a mixture of lichens then I doubt that you will need the green alge. It is encouraging that you have local lichens as this indicates the atmospheric pollution is not a problem. If your 'faux stone' is a cement based product the alkalinity may well be a problem until it has been neutralised by atmospheric CO2. A few regular washes with dilute vinegar might do the trick. As I recall you should find green algae growing on some tree branches, perhaps blackthorn.