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In hydroponic lighting, tube diameter isn’t just a structural detail — it directly affects light distribution, intensity decay, and how effectively your plants can absorb photons for growth. Especially in confined, multi-tier setups, tube thickness can make or break uniform light coverage.
This article compares three common tube types — T5 tube light, T8 grow light, and T15 LED tube — from a hydroponic grower’s perspective, exploring how their design influences light output and plant performance.
T5 tubes deliver focused, narrow beams — great for precision targeting.
T15 tubes cast a much broader spread, covering wider beds with softer light.
T8 sits right in the middle, offering balanced performance in both coverage and intensity.
For a 120cm wide hydroponic tray:
チューブタイプ | Diameter | Light Beam Character | 応用 |
T5 | 16mm | Focused, direct beam, high intensity | Vertical racks, microgreens, herbs |
T8 | 26mm | Moderate spread, balanced beam | Leafy greens, mid-size systems |
T15 | 48mm | Wide-angle coverage, softer output | Fruit-bearing plants, wide NFT trays |
You might think a 24W and a 36W light are directly comparable, but tube shape affects light delivery:
Thinner tubes like T5 have more concentrated output — great PPFD, but in a narrow band.
Thicker tubes like T15 spread light more diffusely — reducing peak PPFD but improving edge coverage.
Sample PPFD results at 30cm height:
チューブタイプ | PPFD (Center @30cm) | PPFD (Edge @60cm) | メモ |
T5 | High | Rapid falloff | Best used close to canopy |
T8 | Moderate | Moderate drop | Balanced for general use |
T15 | Moderate | Strong at edges | Soft, wide-angle beam |
Don’t just look at brightness — consider if the light actually reaches all your plants. Here’s a breakdown by system type:
System Type | Recommended Tube | Why |
Vertical shelf systems | T5 | Slim, low heat, close mount |
Single-layer trays | T8 | Easy to retrofit, balanced light |
Wide NFT beds / tall crops | T15 | Fewer fixtures, broad coverage |
T5 remains the top pick for multi-layer grow racks where spacing is tight.
T8 is the go-to for retrofitting traditional setups or mid-size trays — widely compatible.
T15 is gaining traction in commercial hydro setups due to its efficiency, minimal fixture count, and clean aesthetics.
Note: T15 is larger and heavier — make sure your support frames can handle the bulk, and avoid using it in cramped, lightweight shelf systems.
Choosing the right tube size for hydroponics is about optimizing photon delivery and energy use per square foot. Don’t just compare watts — focus on how light is shaped and spread.
If you’re uncertain about which tube suits your setup, ask yourself:
Is your grow area vertical or horizontal?
Are you growing short herbs or tall, fast-growing crops?
Do you prioritize uniformity, ease of installation, or cost-efficiency?
Feel free to comment or message with your grow setup — I’d be happy to suggest a non-brand-biased lighting plan based on real optical principles.
カスタム照明のプランニングからオーダーメイドの見積もりまで、当社の園芸専門家チームがいつでもお手伝いいたします。
