It can't hurt to try
Though I don't think that one light will be able to put out enough light for the plants. I also am not sure the purpose of reusing the old bulb, unless it's to reflect the light from the
led in one direction with the mirrored surface of the old bulb. I would think it would be much simpler to construct a hood with the reflective surface and attach a bank of Led
lights inside it. That would give it much more light output, and still focus the light in the desired direction. Also I am not sure, but I don't think just any Led light will work to grow plants. They would need to put out the right spectrum's of light to be effective.