Need to replace my 600w MH with LED, need advice

It’s time to replace my ancient 600w MH light with a new LED. A few reasons. Ballast is old, probably will need to be replaced sooner as opposed to later. I want to lower my electric bill. The arcahic light really eats up energy. Also I want to make some room in my 4x4 tent. Between the fan and the hooded light, there no headroom.

So here’s my question.
The old 600w bulb puts out a lot of light. What would be a comparable LED? How many watts?
Looking on eBay there’s some great deals on 200-450w lights. While they promise 4x4 and 5x5 coverage, will they produce the same light intensity as my old MH?


You will want a minimum of 200 watts per plant in flowering.

Be careful about LEDs on both Amazon and eBay. Most of the listing are fraudulent products, despite the reviews you will see. Some of these light sellers are paying customers to fluff up their reviews. To avoid the frauds (they are everywhere,) insist on LEDs built with Samsung LM301 diodes. HLG, Mars Hydro, and Spider Farmer all make decent lights. Avoid lights that output a purple colored light, have integrated fans, and most lights with a daisy chain capability. These cheap lights use too much electricity generating heat instead of light since they are so inefficient.


If budget was my concern I would get a Mars Hydro FC-E6500 , a dimmable 700 watt light.
Will fit in a 4x4 as its 45.75 inches. But you can find brand new ones on ebay for 350 to 400.
If money is not a big issue then an HLG Refurbished Scorpion® Rspec, around 560.00


The only real way to size your led is to size it at 35watt per sq ft of space in your area that your growing in. 40 watt per sq ft would be more then enough.

5 Likes has a 25% off sale that ends today, I believe.


Do I need 640 watts for my 4x4 when it only has one plant in it?


If you fill the 4x4?, Yes do you not agree? About footprint not simple number of plants

Do you need 800 watt for 4 plants in a 3x3?

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If this is the case, then yes. A lot of growers run 1 or 2 plants at a time, particularly new growers, and in that case the footprint of the grow space is irrelevant.

To state that that your way is “the only way” is short sighted and is simply bad advice for a majority of hobby growers in the majority of cases.


Not sure how sizing to a number of plants is better then footprint. To state its bad advice this way is the bad advice…to each there own

So back to my question i need 800w in 3x3? For 4 plants?

How many times have you seen 4 plants in a 3x3? I’d love to see pics.


You serious? Alot of people…hellraiser right of the top…dont be so defensive, i can post alot if really need me 2

And leave 1.5 sq ft (1.25’ x 1.25’) per plant? How does that make sense? I’ll wait for your pics of 4 plants in a 3x3.

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Two plants with 400 watts in a 3x3 does seem reasonable.

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Midwest. Relax. Go look at hells journal then. You know im right, im not going to argue with you.

I’m relaxed, and I don’t see a need to spend time going through Hellraisers posts… I want to see evidence of your argument so we can see if it is reasonable. No evidence = weak argument.


So im wrong? Every1 here seen his journals. Weak is sizing based on number of plants instead of footprint! Period im out! Im not posting other peoples journal to this. Its childish.

Guess im going to have small buds. Im running 560 watt currently not 800 for my 4!


I’m not saying you are wrong. I am saying there are other ways to think about meeting plants’ needs in most situations. Four plants in a 3x3 seems to be the basis of your argument, and that is in no way representative of the practice of the majority of growers.

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