This question comes up all the time. You should refer to graphs of the total solar spectrum which indicate ultraviolet and infrared light frequencies usually - but not always - denoted in nanometer, and ensure the stated frequencies emitted by your proposed bulb are in fact representing the actual environment that Darwin claims was critical to the development of the plant you intend to propogate. Inasmuch as the Elon Musk Tesla Battery effort and others seek to provide solar power to actual cities based on the solar power obviously noted by Darwin as effective for propagation of the species, the requirement in Lumens, wattage, amperage and other measures of energy should obviously to you represent that which the sun also provides in your growing zone. Being an artificial zone however, and modifying the temperature as well as the light in such a way as to recreate nature might be a fun hobby. If you can provide some detail, not only I, but many others will be glad to help.