I have apparently hit a road block in my first attempt at indoor hydroponics.

I planted coriander and lettuce in coco peat grow medium and managed to germinate them. Yaay! Unfortunately after a few days I noticed my babies growing thin and tall. Google tells me this is called "leggy plants" and the main reason is lack of adequate sunlight.
My house does not get direct sunlight in Summer (India), which is awesome for me, but a problem for the plants.
Further googling told me that "grow lights" can fix this. Unfortunately I am not sure which ones to get.

Can I use purple colored LED strips?
What distance should they be from the plants?
How many hours should I leave them on every day?

PS. In case it matters, I am in India where summers mean ~40C on average.

Ok, so yes you are correct, leggy plants are a sign of low light levels, you need more light.
If you suffer from low ambient temperatures led will not offer heat! So you may need to supplement.
Blue spectrum light encourages vegative growth and will keep internode spaces close together, red spectrums really is best for flowering growth so what you really want is a dual spectrum light which encorperates both ends of the light scale.
You can get fancy by using far red spectrum light at the end of the day to mimic the suns going down, which makes plants 'sleep' faster, rest and wake up quicker but I would just stick to a dual or multi spectrum for now. Put led light very close to the canopy, without the heat you can do this, just watch out when they are very young, but they should really be under a flourecent t5 then anyway. Good luck.

Thank you. I have relocated by LEDs to 12" above the plants now. Fingers crossed.

Chris Dubwize wrote:
If you suffer from low ambient temperatures led will not offer heat! So you may need to supplement.
.

40 Celsius = 104 Farenheit

LED's produce no heat so you can bring them right up to the plants, 2-3 inches.

Maneesh Godbole wrote:I have apparently hit a road block in my first attempt at indoor hydroponics.
Further googling told me that "grow lights" can fix this. Unfortunately I am not sure which ones to get.
PS. In case it matters, I am in India where summers mean ~40C on average.

What you want is the type called "Full Spectrum" LEDs, despite the name, these mostly produce light in just the frequencies that plants need.   The actual color is a sort of pinkish purple.  I think the one piece cob style ones are better than the ones made up of a bunch of different separate LEDs.

Roy Hinkley wrote:LED's produce no heat so you can bring them right up to the plants, 2-3 inches.

Of course they produce heat, just not as much as incandescent lights.  In fact many of them get hot enough that the grow light fixtures include cooling fans.