Correction: Non of the seeds were germinated.

Apparently they do need sunlight.

From Wikipedia: Seeds seem to need strong sunlight to germinate, although germination has been achieved even during an average UK summer.

And from an online seed seller: Tulsi seed is a light-dependent germinator, and you can increase germ rates by holding the seed in the palm of your hand in the direct sunlight before planting. Prepare a flat of potting soil or a fine seedbed in spring and scatter seeds on surface, then press in and keep evenly moist and warm until germination, which is rapid. Transplant or thin to 2 to 3 feet apart.

HTH

I did Google to find some information before I posted but I haven't found Tulsi seeds needs strong sunlight to germinate. Sunlight is for photosynthesis it is after the germination.

Information from a website Growing Holy Tulsi

" 4) First Planting (Seeds): In most areas, the first planting is in April, typically indoors in a greenhouse or some protected area. Emulate nature and plant your seeds in earthen pots, if possible, only about one-to-two cm deep, with a light covering of dirt."

Practically I successfully germinated many Tulsi seeds before without sunlight. I also grow many plants from seeds but I never use sunlight for germination.

Many seeds need light - sunlight preferrably - to germinate. It is not just for photosynthesis :-) There are whole long lists of them if you choose to look. Sunlight stimulates the seeds out of dormancy and often if they are covered or blocked from sunlight, germination will be delayed, slow or nonexistent.

And I did find two sources that confirmed what your vendor advised.

Feel free to make of it as you wish.

It is really good for me to know about Photodormancy. I am looking for a list of photodormancy seeds. If Vana Tulsi is one of the photodormancy seeds the seller should put a note of instruction to sow the seeds. Many people said seeds from eBay sometimes problematic.