Lime Sulfur : general purpose Organic fungicide you can make at home

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 A note and caution.

This is a relatively easy process, you don't need to be a chemist or a wizard.  All the ingredients are natural and safe if used with respect.  Wear gloves, a mask and eye protection of course and be warned you may end up smelling a little like a volcano.

Introduction :

Lime-sulfur is a fungicide composed of inorganic sulfur and lime and is commonly used today to control a variety of agricultural fungal diseases. In Australia it is most commonly used as a winter protectant on roses applied after pruning and you will see it for sale under a number of commercial brands in most hardware and gardening stores.

Lime-sulfur is believed to be the earliest synthetic chemical used as a pesticide, being used in the 1840s in France to control grapevine powdery mildew and save their precious wine crop!

Anti fungal preparations are common place in food production, in the 'conventional' farming world the anti-fungal arsenal is extensive and generally toxic to people, to the soil and the environment. 
To avoid putting poisons on our food Organic solutions are however significantly limited. 

While there are a range of options for combating fungal problems in the home garden, from sprays made with garlic , whey, bi-carb, Epsom salts and essential oils, for the farmer the volumes required for crop protection are at a scale that requires some something more practical.

Directions :

Lime-sulfur is a mixture of calcium polysulphides formed by reacting calcium hydroxide (commonly called “brickies lime”) with sulfur.   It is normally used as an aqueous solution for ease of application, and produces a reddish-yellow liquid with that familiar sulfuric smell.


Ingredients and Equipment
I make up 100L at a time but the ratio's can easily be reduced to make a smaller batch. However it will store well and Sulfur is much cheaper when bought by the sack.

Pure (98%) Sulfur should be available from your agricultural supplier and brickies lime / quick lime will be available from any hardware store.

20kg pure Sulfur
10kg hydrated lime / quick lime / 'brickies' lime
100L water

Step 1 :
Put your drum on some bricks and get a hot fire going under it.
Fill the drum 1/2 full with water (approx 100L) and keep the hose handy.

Step 2 :
As the water is coming to the boil, mix the sulfur with a small amount of water to form a paste

Step 3 :
When the water is boiling add all the lime at once and stir until it is dissolved.  You will need a solid stick or broom handle.

Step 4 :
Add the sulfur paste slowly so you don't splash yourself and settle in for a stir-a-thon.
Cook the liquid down for 1-2 hours.

...

You might want to tag team so your arm doesn't fall off.  Moving the thick sediment in the bottom can be a good workout that's best shared with two or more.  Its also a good idea to have an extra pair of hands on deck to keep the fire stoked and the drum topped up the water to maintain the volume as it evaporates.

All the while channel your inner alchemist, enjoy the fragrant aroma of boiling sulfur and marvel at the reaction as the color of your broth changes from pasty white, through hues or orange to a deep red.

Finally :
Allow the liquid to cool (probably overnight),  and depending on how it will be used you may need to strain it through a sieve, or sock etc.
Take the solution from the top of the sediment and strain into bottles.

I typically use a dilution of 1L in 10L water.
Most recently I have been using this application over a custard apple orchard to hopefully treat the phytophthora fungus typical in the tropics and subtropics.   Spraying out about 1L over the trunk, lower branches (avoiding leaves) and drenching the root zone.

Notes :

• Lime-sulfur spray is applied to the woody part of the tree only. Do not spray on foliage as it can burn the leaves.
• Spraying time for fruit trees is dependent on location, weather conditions and indications of disease.
• Spray when there is little or no wind and on a cooler day. Spraying when the weather is warm can stress young fruit trees.

Warnings :

• Wear long-sleeved gloves, protective clothing and protective eye wear when handling lime-sulfur spray. The liquid is caustic and can cause burns to the skin. Keep the liquid away from children. If you have skin contact with the liquid or breathe or ingest the material, seek immediate medical assistance. Wear a face mask for spray application.
• Bees are very susceptible to all fungicides, pesticides, herbicides and fertilizers. Do not spray while the trees are flowering and bees are in attendance to pollinate the blooms.
• Do not spray lime-sulfur on apricot trees.

Hope this is helpful!

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