I don't know the exact mixture but whitewash is made by mixing lime, water, and salt. I think the salt might be a binding agent. When I was young I remember my dad mixing up a batch to paint the walls in the basement with it. Us kids had to wear old clothes cause we weren't the neatest painters at that age, but we had fun hitting each other with the brush.

I've seen many trees with their trunks painted white with something. It is supposed to stop borers from getting into the trees, but I don't know what it is. I'll have to ask James Robin about it. He will know.

noss

Thanks for the insight.

It amazes me that some practices can be done for hundreds of years, the all of a sudden, it just dies out over the course of one, or, two generations. Every fig tree, when I was a kid, had the trunks painted white....now, I haven't seen this done in years.

The lime, water, salt mixture sounds fine for walls/fences...but salt on the bark of a tree?

I guess as the old-timers die off, their garden practices also die off.

Frank

Down here in Arizona a lot of trees get their trunks whitewashed. People use a white latex paint diluted 50/50 with water. The bark of some trees (like citrus) can be damaged by direct sunlight when the sun is as strong as it is down here. I've heard that fig trees can also benefit from the protection that whitewashing offers. I've whitewashed a few trees, but only where the bark was already damaged and there were no leaves to provide shade. Supposedly the sunlight can blister the bark and that becomes a point of entry for insects and disease. My guess is that those old timers who you've seen whitewashing their fig trees originally came from some place with a hotter climate than NYC and are still whitewashing out of habit. The sun isn't powerful enough in NYC to require it.

Joe

In my part of Calif, the trunks of avocados severely pruned for grafting or recovering from fires sometimes get painted white to prevent sun damage.

I know this is an old thread but just thought I would add this for reference:

"Another hallmark of a Mediterranean gardener 'who knows what he is doing' is to whitewash the trunk, and George does just this.

He says it protects the trunk and helps prevent scale. He makes a paste by mixing diluted lime and copper sulphate - which have been diluted separately - and paints this mixture onto the base of the tree.

George applies the paste in August and September annually, just after pruning.

George's recipe for white wash:
George uses a ratio of 3 cups of lime to 1 cup of copper sulphate.
He suggests mixing the three cups of lime with two litres of water, and stir to make a paste; and mix the one cup of copper sulphate with a litre of water and stir to make a paste. This mixture should resemble quite a thick paste, finally mix these together and paint on the tree."

http://www.abc.net.au/gardening/stories/s1335121.htm