How many watts for a 4×4 grow light

A 4×4 ft tent is 16 square feet, about 120×120 cm on the floor. For an efficient white LED, a practical planning range is roughly 30 to 50 watts of actual wall draw per square foot of canopy. That is about 480W to 800W for the whole tent. The middle of that range is why a 600W fixture is the usual recommendation, and it is the draw BAVAGREEN publishes for this footprint.

The published answer is BA-600W-PLUS: a six-bar Samsung LM301H EVO light listed for a 120×120×200 cm tent. The 4×4 kit puts that bar in a 1680D tent with 22 mm metal poles, an inline fan, and a carbon filter. If you already own the tent, start from the 600W buying page. If you are still choosing a floor, read the tent-light guide before you assume every room is a 4×4.

Why the range is 480 to 800 watts

Thirty watts per square foot of efficient LED is a conservative flower target for many home tents. Fifty watts per square foot is the high end of what growers plan when they want more intensity and they can remove the heat. Sixteen square feet times those rates is the 480–800W band. 600W is 37.5 W per square foot, which is why it sits in the middle rather than at either edge.

The range is a planning habit for modern white LED fixtures. It is not a law, and it is not a yield calculator. A cooler room, a short canopy, or a crop that finishes at lower intensity can sit toward the bottom. A sealed room with added CO2 is a different project and is outside what this chart is for. Veg can run well below the flower number if the fixture dims.

Older rules of thumb, such as 50–80 W per square foot, came from less efficient lamps. Applying them to an LM301H EVO bar oversizes the tent. Applying a 600W LED number to an old 600W purple board or to an HPS lamp undersizes the light. The wattage sticker can match while the photon output does not. The LED and HPS comparison is the longer version of that point.

What 600W means on this bar

Listed output for BA-600W-PLUS is 2.90 µmol/J at the fixture and 1740 µmol/s at 600 W. The diode figure on the same listing is about 3.14 µmol/J. Use the fixture numbers when you compare lamps. They include the driver and the red, UV, and far-red channels. They are the manufacturer's published figures for this model. Confirm the current datasheet before you order. They are not a promise about a different wattage.

The fixture size is listed as 1100 × 1100 × 74 mm, so the six bars spread across the 120×120 cm floor instead of sitting as one board in the center. Coverage on the listing is a 120×120×200 cm tent, which is a 4×4 ft floor and a typical interior height of about 6.5 ft. Dimming is 0–100%. UV and far-red have their own control. Certifications on the listing are CE and RoHS. Input is AC 85–265 V. Confirm the plug for your country.

Those photon figures describe the lamp. They do not describe how many plants the tent will hold or what those plants will weigh. Plant count on the 4×4 kit is confirmed on inquiry, because it depends on the crop and on how you train it.

The rest of the kit

The published 4×4 tent listing is 120×120×200 cm, 1680D mylar, and 22 mm metal poles. That is the tent side of the 4×4 kit. The light side is the bar above. The published ventilation on that kit is a 6-inch EC inline fan at 410 CFM, a matching 6-inch carbon filter, 6-inch ducting, and a 6-inch clip-on fan. The 80×80 cm / 240W kit publishes a smaller exhaust: a 4-inch EC inline fan at 212 CFM, plus its own 6-inch clip-on fan. The 4×4 does not reuse that 4-inch duct fan.

If the tent is already built, buy the bar. If you want cloth, poles, light, and exhaust in one shipment, use the kit and ask for the packing list in writing. This site takes the inquiry. It does not check out.

Smaller tents are not a 4×4 at half power

A 2×2 is about 60×60 cm, four square feet. The same 30–50 W per square foot habit lands around 120–200W, which is why published 60×60 systems often sit near 120W or 150W, and why the 2×2 kit is quoted in the 240W class rather than with a 600W bar. The published fixture in that class is the 240W PLUS: 2.90 µmol/J at the fixture and 696 µmol/s at 240 W, on the same listing style as the 600W bar. In a strict 60×60, sales confirms whether that 240W bar or a lower-draw lamp ships. You can also dim the 240W bar.

A 3×3 is about 90×90 cm, nine square feet. The same habit lands roughly in the mid-200s to the mid-400s of watts. That is between the published 240W bar, which is paired with an 80×80 cm tent, and the 600W bar, which is paired with 120×120 cm. The 3×3 kit uses the same published ventilation as the 4×4: a 6-inch EC inline fan at 410 CFM, a 6-inch clip-on, and matching 6-inch filter and duct. The exact light model and draw are confirmed on inquiry. Photon figures on this site stay on the published 240W and 600W sheets.

How to use the dimmer

A 600W bar does not have to run at 600W on day one. Seedlings and clones want a fraction of flower intensity. Dim well down, keep the lamp in the generic starting range on the distance chart, and raise power as the canopy fills. Flower intensity belongs with the PPFD map for BA-600W-PLUS, not with a guess that closer is always better. Leaf temperature matters as much as the tape measure. If the tops bleach, you are too high on intensity or too close, even if the wattage "matches the chart."

Corner plants tell you whether the footprint is really covered. A single board can meter well in the center of a 4×4 and still leave the corners dim. The six-bar form is how this 600W fixture addresses that. Hang it level, keep the tent walls reflective, and avoid stacking a second lamp in the middle unless the map says the edges are short.

What to send with the question

If your question is "is 600W enough?", the useful reply needs the tent height, the crop, whether you dim, and how warm the room is. For a standard 120×120×200 cm tent and an efficient white bar, 600W is the published middle of the 480–800W planning range. The LM301H EVO page explains the diode behind that bar. A room of several 4×4 footprints, or a canopy larger than one tent, belongs on the commercial page, where the same published fixture can be repeated.

Ask for the datasheet, the PPFD map, and the packing list if you want the tent with the light. Name the country so the plug and the lead time are part of the answer.