Best Grow Lights for Seedlings and Clones: Complete 2025 Guide
Updated December 2025 | 12 min read
Starting seeds indoors? Rooting clones? The right grow light makes the difference between leggy, weak seedlings and stocky, healthy plants ready for transplant. This guide covers everything you need to know about lighting for early plant growth.
Key Takeaway
Seedlings and clones need 10-15 DLI (Daily Light Integral) - much less than flowering plants. You don't need expensive high-powered lights. A quality $50-150 LED panel is perfect for most home growers.
Understanding Seedling Light Requirements
Young plants have very different light needs than mature, flowering plants. Understanding these requirements helps you avoid two common mistakes:
- Too little light - Seedlings stretch toward the light, becoming tall and weak ("leggy")
- Too much light - Leaves bleach, curl, or develop brown spots (light burn)
DLI Requirements by Growth Stage
| Growth Stage | Target DLI | Hours of Light | PPFD Needed |
|---|---|---|---|
| Germination (first week) | 5-10 | 14-16 hrs | 100-150 PPFD |
| Seedling (weeks 2-4) | 10-15 | 16-18 hrs | 150-250 PPFD |
| Clone rooting | 8-12 | 18-24 hrs | 100-200 PPFD |
| Vegetative growth | 15-25 | 18 hrs | 250-400 PPFD |
| Flowering | 35-50+ | 12 hrs | 600-1000+ PPFD |
As you can see, seedlings need roughly 1/3 to 1/4 the light intensity of flowering plants. This is great news for your budget - you don't need to spend $300+ on a powerful LED until you're ready to flower.
Use Our Calculator
Not sure how much light your seedlings need? Our free calculator factors in your grow space size, plant type, and growth stage to give you exact DLI and PPFD recommendations.
Calculate Your Light Needs →Types of Grow Lights for Seedlings
Three main types of grow lights work well for seedlings. Each has pros and cons:
1. T5 Fluorescent Lights
T5 tubes have been the industry standard for seedlings for decades. They produce even, diffused light across a large area with minimal heat.
Pros
- Low upfront cost ($40-80)
- Very low heat - can place 2-4" from plants
- Even light spread across wide areas
- Proven, reliable technology
Cons
- Higher electricity cost (less efficient than LED)
- Bulbs need replacing every 12-18 months
- Not powerful enough for flowering
- Bulky fixtures
Best T5 for seedlings: The Hydrofarm Jump Start ($45-55) has been the go-to seedling light for years. It covers a standard 10x20 seedling tray perfectly and includes a height-adjustable stand.
2. LED Seedling Panels
LED technology has improved dramatically. Modern LED panels designed for seedlings are now the best choice for most growers.
Pros
- 40-50% more efficient than fluorescent
- 50,000+ hour lifespan (no bulb changes)
- Full spectrum light
- Some models work for both seedlings AND flowering
Cons
- Higher upfront cost ($60-150)
- Must hang higher (18-24" for seedlings)
- Cheap models have poor quality drivers
- Point-source light (less even than T5)
3. LED Light Bars (Clone/Seedling Specific)
Some LED fixtures are designed specifically for propagation (seedlings and clones). These are lower-powered but optimized for early growth stages.
Pro Tip: The "Grow Then Upgrade" Strategy
Many experienced growers use a dedicated seedling light ($50-80), then transfer plants under a more powerful LED ($150-400) for vegetative and flowering stages. This is more efficient than running a high-powered light at low intensity for seedlings.
Best Grow Lights for Seedlings (2025 Recommendations)
After testing dozens of lights and reviewing grower feedback, here are our top picks for seedling grow lights in each category:
Best Budget Option: Spider Farmer SF300
Spider Farmer SF300 LED Grow Light
Perfect for 2x2 ft seedling area. Samsung LM281B diodes, full spectrum, dimmable. Can be used through veg stage.
- Power: 33W (actual draw)
- Coverage: 2x2 ft for seedlings, 1.5x1.5 ft for flowering
- Spectrum: 3000K + 5000K + 660nm red
- Lifespan: 50,000+ hours
$59.99
Check Price on AmazonBest for Multiple Trays: Mars Hydro VG80
Mars Hydro VG80 Seedling Light
Designed specifically for seedlings and vegetative growth. Higher blue spectrum promotes compact, bushy growth.
- Power: 80W (actual draw)
- Coverage: 2x4 ft for seedlings
- Spectrum: Enhanced blue + full spectrum
- Daisy-chainable for larger setups
$79.99
Check Price on AmazonBest T5 Fluorescent: Hydrofarm Jump Start
Hydrofarm Jump Start T5 System
The classic seedling light. Includes adjustable stand, perfect for one standard 10x20 seedling tray. Proven over 20+ years.
- Power: 24W T5 tube
- Coverage: 2 ft length (one seedling tray)
- Includes: Reflector, stand, tube
- Height adjustable 8" - 16"
$49.99
Check Price on AmazonBest Premium Option: AC Infinity IONBOARD S22
AC Infinity IONBOARD S22
Versatile light that works from seedling through flower. Samsung LM301H diodes (top tier). Excellent build quality and 5-year warranty.
- Power: 100W (dimmer to reduce for seedlings)
- Coverage: 2x2 ft (full cycle)
- Spectrum: Full spectrum + deep red
- Features: 0-100% dimmer, passively cooled
$129.99
Check Price on AmazonGrow Light Comparison Chart
| Light | Type | Wattage | Coverage | Price | Best For |
|---|---|---|---|---|---|
| Spider Farmer SF300 | LED | 33W | 2x2 ft | $60 | Budget + grow into veg |
| Mars Hydro VG80 | LED | 80W | 2x4 ft | $80 | Multiple trays |
| Hydrofarm Jump Start | T5 Fluorescent | 24W | 2 ft | $50 | Single tray, proven |
| AC Infinity S22 | LED | 100W | 2x2 ft | $130 | Full cycle (seed to flower) |
Seedling Light Setup: Step by Step
Follow this process for best results:
Choose Light Height
Start with LED lights 24 inches above seedlings. T5 fluorescents can be 4-6 inches away. Adjust based on plant response.
Set Timer for 16 Hours
16 hours on / 8 hours off works for most seedlings. Cannabis clones often do better at 18/6 or even 24/0.
Watch for Stretching
If seedlings become "leggy" (tall, thin stems), move the light closer or increase duration. This is the most common seedling problem.
Watch for Light Stress
Bleached leaves, brown spots, or curling edges mean too much light. Raise the light or dim if possible.
Gradually Increase Intensity
As seedlings grow true leaves (not cotyledons), gradually lower the light or increase dimmer settings over 1-2 weeks.
Clone-Specific Lighting Tips
Clones have unique lighting needs compared to seedlings:
- Lower intensity needed - Clones don't have roots yet, so they can't process as much light. Keep intensity 25-50% lower than seedlings.
- Higher humidity matters more - Without roots, clones absorb water through leaves. High humidity (70-80%) reduces stress.
- 18-24 hours of light - Many growers use 24/0 for clones to prevent stress from darkness.
- Cool light preferred - T5 or LED at 18-24" keeps dome temperatures stable.
Clone Dome Warning
Never place a powerful LED too close to a humidity dome. Heat buildup can cook clones. Keep LEDs at least 24" above dome lids, or use a T5/low-power LED designed for propagation.
Common Mistakes to Avoid
Mistake #1: Using Household Bulbs
Regular LED or CFL bulbs from the hardware store won't work. They lack the proper spectrum (PAR) that plants need. You need purpose-built grow lights.
Mistake #2: Starting with a Powerful Light
A 300W LED is overkill for seedlings. You'll waste electricity and risk light burn. Match light intensity to growth stage.
Mistake #3: Inconsistent Light Schedule
Seedlings need consistent light cycles. Invest in a $10 mechanical timer. Inconsistent lighting causes stress and irregular growth.
Mistake #4: Ignoring Light Distance
The same light at 6" vs 24" delivers wildly different intensity. Always check manufacturer recommendations and adjust based on plant response.
Budget Seedling Setup: Under $100
Here's a complete seedling setup for under $100:
- Spider Farmer SF300 $60
- Mechanical Timer $10
- 10x20 Seedling Tray (2-pack) $15
- Humidity Dome $12
- Total $97
Frequently Asked Questions
How many watts do seedlings need?
Seedlings need 15-30 watts per square foot of LED light, or 30-50 watts per square foot of fluorescent light. A typical 10x20 inch seedling tray (1.4 sq ft) needs 20-40W of LED or 40-70W of fluorescent lighting.
How far should grow lights be from seedlings?
LED grow lights should be 18-24 inches from seedlings. T5 fluorescent lights can be placed 2-4 inches away. Start higher and gradually lower if seedlings become leggy (stretching toward the light).
Can I use any LED light for seedlings?
No. Household LED bulbs lack the proper spectrum for plant growth. Seedlings need lights with wavelengths in the 400-700nm range (PAR). Purpose-built grow lights or full-spectrum horticultural LEDs are necessary.
How long should grow lights be on for seedlings?
Seedlings need 14-18 hours of light daily. Most growers use 16 hours on / 8 hours off. This mimics long summer days and promotes vegetative growth without stressing the plants.
T5 or LED for seedlings - which is better?
Both work well, but LEDs are generally better for most growers in 2025. LEDs use 40-50% less electricity, last 5x longer, and produce less heat. T5s are cheaper upfront but cost more over time. LEDs are the better long-term investment.
Final Recommendations
For most home growers starting seeds indoors, here's my recommendation:
- Best overall: Spider Farmer SF300 ($60) - Great value, can grow with your plants into veg stage
- Budget pick: Hydrofarm Jump Start ($50) - Proven, reliable, includes stand
- Premium: AC Infinity IONBOARD S22 ($130) - Full-cycle light, excellent build quality
Remember: seedlings don't need much light. A $50-80 dedicated seedling light will serve you well for years. Save the high-powered LEDs for flowering!
Calculate Your Exact Requirements
Use our free grow light calculator to determine exactly how much light your seedlings need based on your grow space, plant type, and goals.
Use the Calculator →