Kitchen remedies for pest control
Anecdotally the following remedies are useful for pest control.
Lethal drinks for slugs and snails
Lay a jar on its side, partially buried so the lip is flush with the soil. Pour in beer, wine or a yeast beverage as these attract the slugs and snails which drown in the liquid. For optimum results place the jars in cool damp spots.
An alternative is to spray seedlings and surrounding soil with one part strong espresso coffee to 10 parts water. The theory is that slugs and snails crossing the soil absorb caffeine and die. This solution should be re-applied after rain.
Milk spray for powdery mildew
This is effective provided you get good coverage of the foliage or fruit. Applications should be no more than 10 to 14 days apart, depending on the weather.
Mix one litre of water with 100ml of milk (or 200ml if the disease is well established). Fresh or powdered milk can be used. Full cream milk is slightly more effective than skim milk. Applications work best if applied as soon as the disease is noticed. Milk is unlikely to eradicate the disease once it is established.
Bicarbonate sprays for fungal diseases
These are used on powdery mildew and black spot. The bicarbonate may be sodium bicarbonate, commonly called bicarb of soda, available from grocery stores or potassium bicarbonate which can be bought from some hardware stores.
Mix 10g (about two teaspoons) into one litre of water and add 2-4ml of horticultural oil. Again, full coverage and regular applications are critical.
Some recipes substitute vegetable oil for horticultural oil but, bicarbonate sprays in particular are likely to burn leaves if used on hot days.