Vertical growing stacks layers instead of renting more floor space. That runs straight into the reason an ordinary grow lamp does not work there: it needs height to spread its light, and the heat it gives off goes directly into the layer above.
Why height is the problem here
A panel that throws an even pool at eighty centimetres throws a hot core with dark edges at twenty-five. In a stacked setup you do not have those eighty centimetres. So you need a fixture that is already even at short range and pushes little heat into the next layer. That is a different design, not a smaller version of the same one.
The Lumatek VF Series
This LED fixture is built for exactly that: a slim bar that hangs close above the canopy without scorching it, with a light spread that is even at short range. You choose the wattage when ordering, VF90W or VF120W, and whether to take the matching driver. Work out the power per layer rather than per room, because each layer is in effect its own grow space with its own light requirement.
The driver belongs with it but is not attached
The Lumatek 650W VF Series Driver runs several bars at once, which is why it is chosen separately from the lamp: with one layer you may not need it, with four you will. Take it as an option on the product, or separately under Power Supplies & Drivers. Budget for it, because without a driver you have a bar that will not switch on.
Air is a bigger problem here than light
Between two closely stacked layers the air goes still faster than you expect, and still humid air against the leaf is exactly where mould starts. Plan for more circulation than in an ordinary tent of the same floor area, and for movement between every layer rather than only above them.
Frequently asked questions
Can I hang an ordinary panel in a stacked setup?
Usually not well. At the short range a layer gives you, a panel throws an uneven pool and too much heat upward. That is what a bar is for.
Do I need the driver?
It depends how many bars you are running. With one layer often not, with several yes. You choose it when ordering.
How much power per layer?
Work it out per layer as though each were its own grow space. Four layers of half a square metre need more between them than one two square metre room, because each layer needs its own coverage.
