How to choose the right discharge lamp?

The following lines will reveal the answer to one of the most common questions of beginning growers who use grow tent as a source of artificial lighting for cultivating plants: HID lamps. Do you already know how many watts will be just right for you?

When it comes to the parameters of high-intensity discharge lamps (HID), the wattage of artificial lighting for your plants that will be appropriate given your growing space and plans can be estimated as follows:

• 70W lamps are intended to illuminate a growing area of 35 x 35 cm with an effective reach of 25 cm.
• 150W lamps are intended to illuminate a growing area of 45 x 45 cm with an effective reach of 35 cm.
• 250W lamps are intended to illuminate a growing area of 60 x 60 cm with an effective reach of 50 cm.
• 400W lamps already allow reliable coverage of 1 square meter of growing area with an effective reach of 80 cm.
• 600W lamps are intended to illuminate a growing area of 120 x 120 cm with an effective reach of 1 meter.
• 1000W lamps can easily cover a growing area measuring 150 x 150 cm with sufficient light intensity.

We must not forget, however, that an important prerequisite for the above values is the use of a quality reflector (shade) in combination with a high-quality reflective material inside the growing space.

Our TIP: Take advantage of the exceptionally favorable price-performance ratio offered by LUMii Black Digitální komplet 600W KIT. Not only is it one of the bestsellers, but besides the lamp and ballast it also includes a quality reflector in the price!

As for the number of watts, there are some generally accepted rules among growers:

• Mother plants and cuttings (clones) require at least 20 watts (W) per square foot. A square foot is equivalent to an area measuring 30 x 30 cm.
• During the flowering phase, stronger lighting is needed, namely 25 to 40 W.
• The higher the output of the grow lamp, the lower the wattage per growing area you need.
• Many growers solve the situation elegantly by replacing a single large lamp with several smaller ones whose wattages add up to the same total. The difference between the two options—and the advantage of the second—is more even light distribution. This applies of course especially to HID lamps, while modern LED lighting will provide even light distribution on its own.
• Keep in mind that the intensity of radiation reaching the plants quickly decreases as their distance from the lamp increases. In practice you will find that each HID lamp has a certain reach that is sufficient for producing the flowers and fruits you want. And again, unlike LED technology, you must subtract a safe distance from this reach to the tops of the plants to avoid burning them with the lamp! How effectively heat is removed from the plant tops depends substantially on the ventilation you have in your grow tent ventilation—in other words, how and how efficiently heat is carried away from the plant tops.
• Reach (see above) is also related to the height that the planted specimens will grow to. You need to consider this. A perfect solution even for taller varieties, so you can cultivate them without the risk of burning their tops, are grow tents with increased height, such as Dutch Mammoth grow tents HC or HOMEbox Ambient marked with a plus sign.

If you need advice choosing one or more HID lamps, do not hesitate to ask us anything via the well-known e-mail address info@higarden.cz.

We also recommend these products:

• Spectromaster 250W HPS lamp (449 Kč)
• Spectromaster 400W MH lamp for growth (649 Kč)
• Lumatek 1000W 400V DE Růst i Květ HPS (2 599 Kč)

What to read next?

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