Is my LED light strong enough?

[iwanttoknow]

On my 2nd grow using MAXSISUN PB2000, 200W LED Grow light. Getting decent results but just think the yield could be greater. What upgrades can I make to the current light?
My grow area is an un-used bathtub, the walls are covered with silver Mylar space blankets, the long side of the tub area is closed in with Styrofoam insulation board with silver backing on one side.
I can control the temperature somewhat, but the humidity level is a bit harder to control as this is an indoor grow that is controlled by the central AC that is necessary in the Gulf South all year round.
I use Fox Farm Happy Frog and Ocean Forest with the recommended nutrients.
I can fit 4 or 5, of the 3 gallon cloth grow bags. The most recent harvest of 3 plants was 3.8oz, just a little over an ounce per plant (dried and trimmed weight)
What changes do I need to make for higher yield in the limited space available? Larger grow bags, stronger light? Advice and recommendations are welcome.

[Ckbrew]

Stronger light. Light is what plants really "eat" to grow. For that number of plants, I would go with a 400W light like spider farmer SF4000. If your grow area is in a tub I'm thinking it is oblong. You may do better with a second 200W light side by side for better coverage.

[Ace1973]

I would go a little higher in the actual watts, I use a mars hydro TS 3000(450 watt actual), before that I used a 400 watt hps. It really depends on your square footage.

[SoOrbudgal]

I hope you have more than 1 bathroom LOL

[GroBuddy]

Multiply your tub width and length, divide that by lights wattage. As mentioned you'll probably want two since tubs are longer than wider. You will want a minimum of 30 watts a sqft from a quality light. Cheaper the light the more wattage per sqft youd want. For example: ( grow space ) 3ftx3ft= 9 sqft 200 watts ÷ 9 = 22 watts a sqft

[90Gizmo]

I used the same 240 watt light in a 2x4' tent for the start of my first three plant grow. I think the PB2000 is more for a square area than a rectangular one. I added an additional 100 watt light to make the coverage more rectangular. I thought having the second light also gives me the flexibility to use it somewhere else if, say, I only have one of two plants in the the tent. I did make a hood for the second light out of alu baking pans. I think that feature of the maxsisun and others helps bring up the par levels in the corners. Not to mention that it helps keep it out of your eyes. I figure the usable area of my tent is 2 by 3 feet now. With 340 total watts that's 56 watts per square foot... I guess my takeaway is that the shape of your light's useful par map should match your grow area. Hope that helps.

[SoOrbudgal]

That's friggin excellent idea 90Gizmo with using those pans great way to increase reflection

[90Gizmo]

Thank you! The Maxsisun comes with the reflector and I think that gives it better numbers in the corners. After looking at it though it would be impossible not to think "aluminum baking pan."

[90Gizmo]

However, I think the reflector implementation on the PB2000 causes the LEDs to run a little hot. The dimpled reflector runs between the LED panel and the full-panel heatsink and the dimples insure that the LED panel is not in very good contact with the heatsink. The driver also runs a little hot so I set a heatsink on top of it too. Neither of those things effect how hot the tent gets (watts is watts) but I figure better heat dissapation equals longer life for the light.

[Ckbrew]

Speaking of heat dissipation, I run a clip on fan attached to the ceiling of the tent above the light blowing directly down on the light as a dedicated cooling fan. It keeps the lights at a comfortable temperature. Also I have some heat sinks salvaged from computer CPUs on top of the drivers. The cooler the electronics run, the longer they will last.

[iwanttoknow]

Ckbrew "You may do better with a second 200W light side by side for better coverage." I think adding a 2nd PB2000 is what I will do for now, since I already have a 2nd light. Just sprouted a few Pineapple Chunk seeds, will see if double the amount of light (and trying to follow instructions from BU2B for a pound per plant) yields are better than the past grows (Just glad this is for recreation and not medication ) Thanks to everyone that gave info.

[iwanttoknow]

GroBuddy if I am using your formula posted above, I estimate the usable area is 2' x 4' = 8 sq ft., using 2 lights would double the watts to 400? so 400 / 8 = 50 watts? Should be way more than enough light to fatten the yield! Please confirm if my calculations are correct. TIA

[GroBuddy]

50 maybe too much idk it's a maxsisun you may could get away with that. More wattage past a certain extent you'll need co2. 250 to 300 watts would be sufficient

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Get 2 of these or 3 of these

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