The plants have different needs depending on their stage :

– rather blue for growth, this promotes the foliage and shorter inter-nodes.

– rather red for the flowering

Fluorescent Tube



High output fluorescent lighting system


The fluorescent tube is used for domestic and industrial lighting. It is often mistakenly called “Neon”, the name of the gas originally contained in the tube (neon produces a red light). Its advantages are its low power consumption and long life.

In indoor growing,  the advantages:
to be easy to find (DIY Stores)
the relatively low cost
a relatively small exotherm
to be declined in many lengths
However, due to their low power and light output, they are particularly just suitable for vegetation phase. In bloom, it takes a significant number of it in order to have a correct flowering. And in this case, power consumption is equivalent to a HPS lamp.

The disadvantages are:
a light output of only 50 to 60lm / watt
a low penetration
not effectively emit the middle of the tube, the ends being ineffective
The fluorecents tubes for horticultural use to be replaced at most every year. They begin to lose their luminous efficiency from 6 months even though their life may reach 2 or 4 years.
Use tube for aquarium plant, some spectra available are suitable for photosynthesis (Grolux type pink color).

Vegetative growth is quite long and the light is not penetrating.
Distance fluorescent tube / tops: 5/10 cm
Power: 18, 36 watts

They are not really suitable for flowering.


Compact Fluorescent Lamp or CFL Lamp

Cfl lamps are excellent for mothers and cuttings and are also suitable for the flowering according to the selected color temperature. CFL are not nearly as good as HPS / MH but allows to have a very good result to grow cannabis.

Some models require a ballast, be careful if you opt for this lamp. In addition, because of their shape, Cfl lamps are very fragile ampoules, must be handled by the base.
Their low light clearance avoids any risk of apical chlorosis.
It can therefore be closer to 1 cm from the top of the plants.
Cfl lamps are are available in different spectra and power.

However, as with other lamps, the light intensity will decrease:

250W: 24696 lumen
Growing Cannabis with Cfl lamps (depth 37cm) – Actual depth of 36cm on 0,49m²
200W: 20160 lumens (depth 30cm) – Actual depth of 29cm on 0,4m²
150W: 15120 lumens (depth 22cm) – Actual depth of 21cm on 0,3m²
125W: 12600 lumens (depth 19cm) – Actual depth of 18cm on 0,25m²
95W 8900 lumens (depth 14cm) – Actual depth of 13cm on 0,19m²
65W: 6090 lumens (depth of 9cm) – Actual depth of 8cm on 0,13m²

Lifetime: 22,000 hours (just over 3 years) but it is not as effective after 15,000 hours.
Growing Cannabis with Cfl lamp


MH Lamps (Metal Halide)

Spectrum is ideal for vegetative growth.
Lifetime: ~ 12 months

23,000 lumens for a 250 watt bulb
42 000 for a 400 watt bulb
50,000 lumens for a 600 watt bulb

Cannabis metal halide lamps

Cannabis metal halide lamps


HPS or High Pressure Sodium bulb

Ideal spectrum for flowering. For economy, it is quite possible to use HPS bulbs intended for public lighting (orange).
The “horticultural” Grolux type Sylvania lamps or Green Power (T-Pia technology *) Philips are a plus, they have a slightly improved spectrum.
These bulbs are a plus, but not the guarantee of a better harvest.

33,000 lumens for a 250 watt lamp
55 000 lumens for a 400 watt lamp
90 000lumens for a 600 watt lamp
110 000 lumens for a 1000 watt lamp
Lifetime: ~ 12 months
Some people change the bulb after each crop to maintain optimum illumination, but you can use it for 8 months max.

Distance: it depends on the lamp power and ventilation
Requires a strong and continuous ventilation.
Not recommended for young plants and cuttings.
A cooltube lighting system is recommended if you want it closer to the plants.

Growth in HPS
It is perfectly possible to make a growth in HPS though:
the internodes are longer compared to colder lights

Autoflowering cannabis plants under 400w hps lamp

Autoflowering cannabis plants under 400w hps lamp



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