Lime-based whitewash

In the July/August 2013 issue of Organic Gardener magazine, Phil Dudman explains how to prune citrus trees, including cutting an old tree back severely if needed. He also mentions that painting the trunk for protection is important. Here is Phil’s explanation of how to make a whitewash for this purpose.

Lime whitewash

If heavy pruning of you fruit trees has exposed the trunk and branches to sunshine, it’s important that you paint the bark to protect it from sunburn and splitting. 

Organic gardeners traditionally use a lime-based whitewash made from hydrated lime, water and oil. Hydrated lime (also known as slake or builder’s lime) is readily available from hardware stores and building suppliers. It’s very caustic, so be sure to follow the safety directions on the pack. When handling, avoid contact with skin and eyes and avoid breathing the dust (wear suitable gloves and eye/face protection).

Adding oil helps the wash to stick. Linseed oil is the traditional choice, or you can use horticultural oils such as eco-oil and Pest Oil. Follow these directions:



Step 1 - Pour 500ml of water into a bucket.


Step 2 - Add 1 cup of hydrated lime.


Step 3 - Pour in 5ml of oil.


Step 4 - Mix together and add more water or lime until you have a smooth slurry similar to the consistency of house paint.


Step 5 - Slop it on with paint brush. Don’t worry if it gets on your clothes, it washes off quite easily.



The finished tree.

The whitewash is not paint so it will wear off gradually, by which time the tree canopy should be re-established.

First published: May 2013

Related topics

Pests, Diseases & Weeds, Garden Tasks, Solving Problems, Issue 68 - July/August 2013, How to…, Pruning