Basic Fungicide Recipe
1 ts baking soda
1 litre water
1 ts dish soap or safer's soap
Mix together, spray on. Be sure to cover the complete plant, including stems, leaves and top of soil. Also be sure to spray both sides of leaves. Spray every 3-5 days to control the problem, especially while weather conditions favor fungal diseases. Use preventatively every 2 weeks.
Best Botrytis Buster (Bordeaux Mix)
If your plants suffer damage through the growing season or start to show botrytis spots, immediately spray with this mix!
3 1/3 tablespoons copper sulfate
10 tablespoons hydrated lime
1 gallon water
Dissolve copper sulfate in plastic or glass container with 1/2 the water thoroughly, leave it sit and come back later if you have to, it MUST be dissolved. In a separate plastic container mix the lime powder very well with the rest of the water. Slowly pour the lime mixture into the copper mix, stir thoroughly before use. Spray with a plastic sprayer, metal cannot be used with copper! Be sure to shake or stir up the mix as you spray so particles stay suspended in the water and do not settle.
Copper sulfate is often referred to as bluestone, and hydrated lime is the same as calcium hydroxide. Both are readily available at farm supply stores such as Peavey Mart or UFA (in Alberta).
This is an age old recipe that in my opinion still works the best, is the cheapest and covers the widest range of fungal problems on the widest range of garden plants - if you grow roses you should know this simple spray will outperform ANY product you can buy to control rose diseases!
Davidson Bordeaux Recipe
This recipe was sent to me by one of my favourite customers, Mr. Dennis Davidson. Here's what he had to say:
I developed a formula that is easier to mix and achieves the same results - total control.
2 ml Wilson's Bordo Copper Spray Powder
2 ml Laters Phaltan (Folpet 50%)
1 litre water
With either this formula or yours, greater effectiveness can be had by adding a surfactant (soap for instance). Keep shaking sprayer tank as you spray. I find too that spraying upwards to hit the undersides of the leaves can give even better control. Repeat spraying after a rain or fog is important. Who cares if the leaves are blue? Better than brown, rotting and dead.