Activity of applying fertilizers directly on plant leaves which in turn gets absorbed directly through the leaves is called foliar feeding. Effect of foliar feeding is quick but short-lived.
Foliar feeding helps when plants that have suffered serious root damage, one can apply liquid fertilizer as a foliar spray to the plant leaves.
Fish emulsion is a best example.
If you have any home-made foliar feed recipe please share in comment or write to me here
Happy gardening !