Answer: I assume you are referring to starting them indoors. Leggy seedlings are usually caused by lack of sunlight. He should try starting them only 6-8 weeks before transplanting outside. Any longer than that and they almost always get too spindly.
Nothing beats sunlight! The important things when choosing a light source are that the bulb doesn't give off excessive heat, and that the light is as close as possible to sunlight--that is, it covers the full spectrum, containing both "cool" and "warm." (Cool and warm refers to the color spectrum, not the temperature of the lights.)
Fluorescent lights satisfy the "cool" requirement, and they are reasonably close to full sprectrum. Or you can purchase full spectrum grow lights. Because indoor lights aren't nearly as bright as sunlight, you need to be able to keep the lights 4-6 inches from the top of the plants, adjusting that as they grow. Lights should be on 16 hours a day and turned off at night. Putting them on a timer is helpful.
I hope this info is helpful!
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