What Light Should You Use for Indoor Cannabis? Complete Guide to CFL, MH, HPS, CMH and LED Grow Lights (2026)

Lighting is the absolute foundation of any indoor grow setup. In nature, plants rely on sunlight, but in controlled environments we must replace it with an artificial light source that delivers the correct amount of photons required for photosynthesis.

That’s why choosing the right grow light is the most important decision you will make at the beginning of your indoor cultivation journey.

Over the years, growers have used many different lighting technologies: from CFL fluorescent lamps, through MH and HPS systems, to modern CMH and LED grow lights. Each has its own purpose, advantages, and disadvantages – and some are slowly becoming outdated.

What Type of Light Do Plants Actually Need?

Plants do not use the entire light spectrum – the most important part is PAR (Photosynthetically Active Radiation), which represents the wavelengths used in the photosynthesis process.

Blue spectrum light supports leaf and vegetative growth, while red spectrum promotes flowering and bud development.

This is why different types of grow lights are traditionally used for different growth stages: MH for vegetative phase, HPS for flowering, while LED or CMH can be used as full-spectrum lighting throughout the entire life cycle of the plant.

CFL Grow Lights – The Cheapest Entry-Level Option

CFL (Compact Fluorescent Lights) are one of the simplest and most affordable lighting solutions for beginners. They emit relatively low heat and do not require an external ballast, making them ideal for small grow tents, clones and seedlings.

However, their downside is low output power and poor light penetration – which makes them unsuitable for larger plants or heavy flowering cycles. CFL is best used as supplementary lighting or for early-stage development.

Example: CFL 85W Elektrox Flower

MH Grow Lights – Ideal for Vegetative Growth

Metal Halide (MH) lamps emit more light in the blue spectrum, which supports strong root and leaf development. That’s why MH lamps have been used for decades during the vegetative phase.

MH belongs to the HID (High Intensity Discharge) lighting family, similar to HPS systems. These lamps require a compatible ballast in order to function correctly.

Example: MH 600W Sunmaster

HPS Grow Lights – The Classic Flowering Standard

HPS (High Pressure Sodium) lamps have long been the gold standard in indoor cultivation. They emit strong red-orange spectrum light that promotes flowering and significantly increases yield potential.

Their main disadvantage is high heat emission – a significant portion of energy is converted into infrared radiation, which requires proper ventilation.

That’s why when using HPS systems, you should always install:

• carbon filter
• inline duct fan
• cooltube reflector

CMH Grow Lights – A Hybrid Between HPS and LED

CMH (Ceramic Metal Halide) lamps combine the benefits of both MH and HPS technologies. They provide a wide light spectrum similar to natural sunlight, making them suitable for the entire growth cycle.

They generate less heat than traditional HPS systems and offer a longer lifespan, but their initial cost is higher.

Example: Lumatek CMH 630W

LED Grow Lights – The Modern Standard

Modern LED grow lights offer full-spectrum lighting while consuming significantly less electricity. They can use up to 40% less power than HPS systems and emit much less heat.

Additionally, their lifespan can exceed 50,000 hours of operation, making them the most cost-effective long-term lighting solution.

Example: GOAT LED EVO 150W

Check also: LED Grow Light Ranking

Ballasts – Magnetic vs Electronic

MH and HPS lamps require a ballast. There are two main types:

• Magnetic ballast – cheaper, but less efficient
• Electronic ballast – more stable and energy-efficient

Examples:

• Horti Gear 250W
• Fortis 600W Electronic Ballast

Summary – Which Grow Light Should You Choose?

• CFL – for beginners and small grow tents
• MH – for vegetative growth
• HPS – for flowering
• CMH – universal HID solution
• LED – best option for full cycle

For smaller grow tents we recommend: RoyalRoom Classic 60x60 Grow Tent