A lot has been said about using foliar fertilisers, what I have gathered from the forum and internet is;
Foliar feeding is considered especially useful for introducing trace elements, or for "emergency" feeding of plants which are found to have a specific shortage. But in some cases, with tomatoes, for example, it is believed that foliar feeding during flower set causes a dramatic increase in fruit production.
All water soluble fertilisers can be used as foliar fertilisers.
Results from the experiments quantified plant nutrients moving at the rate of about one foot per hour to all parts of the plants after spray.
Nitrogen is absorbed in ½-2 hours
Phosphorus 5-10 Days
Potassium 10-24 Hrs
Available Grow more USA 20-20-20 with micro nutrients
Italian 20-20-20 with micro nutrients
Other ratios are also available
Recommended dilution 20-20-20 =0.2-0.4% which amounts to 400-800 parts per million Nitrogen
Recommended interval between spraying during growing season is fortnightly.
Is it correct? Should I go ahead? Can I mix fungicide or insecticide with it?