Hydroponic gardening is most always done indoors.
That immediately eliminates the benefit of the sun shining down on your plants to nourish them.
Yes, if you have a small indoor garden - maybe an herb garden - you may be able to set that in a window and it may get enough sunlight.
But generally, you are going to need to provide light for your hydroponic garden plants.
When it is time to purchase your grow lights, go to the local place that will have a good selection and someone who knows about and understands indoor gardening.
What plants and how much you are growing will determine which lights are best for you.
If you are just growing one tomato plant, then a fluorescent or Metal Halide light will work well.
However, if you are planting a large garden with different types of plants, you will want to choose a more powerful light such as a High Pressure Sodium light.
The intensity of the light is measured in lumens and each light will have a different lumen measurement.
The amount of lumens you need depends on the types of plants you are growing as well as the number of plants you have under the light.
Indoor hydroponic gardening grow lights need to be set as close over your plants as possible without burning the plant.
That means that as the plants grow, you will need to be able to adjust the height of the light to match the height of the plant.
Also these grow lights often put out a considerable amount of heat.
You will need to make sure your plants are getting enough ventilation.
This can be done by setting up a small fan to cool your plants down enough so that they can grow and produce.
It will take a little money (or more if you want the fancy growing closets) to get started with your hydroponic indoor garden, but the rewards will be unbelievable.
Your plants will amaze you with their rate of growth and you will have fresh produce on your table all year.