Panchagavya is a boon or curse to newly born Tulasi plant
I just planted tulasi seeds in pots and they sprouted and grew some 5-10 cm long. I used panchagavya as a fertilizer. But after an hour or 2 after the application when I checked on my plant, the leaves where the panchagavya got in contact while sprinkling on them turned a bit black. Is it going to harm my Tulasi?
Basil may need only a light fertilizer application. If the soil is of good quality, this is likely enough nutrition for the plant.
It sounds as if you burned the plants with direct contact from a fertilizer.
Here are some links with more information.