The Hydroponics Blog

I really have to talk about this subject.

Back when I started hydroponic growing, on ill advice I had my lights way too close to the plants.  Try a 250W about 12 inches from the tops of baby plants.  That’s just plain crazy.

Now I aim for 36 – 48 inches away from the baby plants, 48 ideally if you have space.

You can cover around 3 square metres with a 250W light, much more than you would expect.  The plants will stretch if light is inadequate, so don’t worry.

Too close to the light and the plants will stunt and stress…you’ll see the problems more during flowering.

Come flowering, I try to keep the light 36″ away also, too close and it nukes the flowers.  Tying plants down helps if the strain can take it.  I’ve always been a fan of 400W and 600W lights for flowering, because they might stress the plants less than a 1000W.

A good tip is to use a old 400W or 600W bulb for the initial flowering stages, this gives the plants time to get used to the new wattage.  Then move to a brand new 600W bulb for maximum flowering.