Yes, basil can grow indoors under a Sansi 40 W grow light.

Yes, you can grow basil indoors with a Sansi 40 W grow light, but the wattage alone cannot tell you whether your plant gets enough light. A grower reported slower basil growth indoors under this bulb than on a balcony. That comparison is one growing experience, not a controlled test of the lamp.

Judge the light reaching the leaves

Wattage measures electricity use, not the amount of plant-usable light at the leaves. A phone light sensor can also give a misleading reading under a grow light. For plant lighting, PPFD is more relevant than a phone's lux reading, though the distance from the lamp and the area it covers still matter. Follow the lamp maker's guidance for placement and safety.

Basil is a high-light herb. Check for leggy stems, long gaps between leaves, or pale growth, which can indicate insufficient light. Bleached or scorched leaves can indicate stress, including excessive light or heat. Also check watering, temperature, pot size, and airflow before blaming the lamp; balcony and indoor conditions differ in several ways.

To compare changes, note the lamp distance, daily operating time, watering, and new growth over several weeks. Change one condition at a time. The available account does not establish a universal distance or schedule for every Sansi bulb, basil plant, or room.