My seedlings look like they're reaching desperately for my grow light and keep falling over. The light is 8 inches above the tray. Is it too far away, or is this because I'm running 24 hours of light?

This is one of the most common seedling problems and it has a specific, fixable cause. The stretching behavior you're seeing is called etiolation - the plant's response to insufficient light intensity.

Why distance is the main problem

Light intensity follows the inverse square law: when you double the distance between a light source and a plant, intensity drops to one-quarter of what it was. Conversely, halving the distance quadruples intensity.

At 8 inches, most consumer LED grow lights (including AeroGarden units, cheap Amazon panels, and even mid-range grow bars) are delivering too little intensity for compact seedling development. Moving to 4 inches quadruples the light reaching your seedlings.

For seedlings, the target light height:

• Budget LED panels under 50W: 2–4 inches
• Mid-range LED grow bars (50–100W): 4–6 inches
• Full-spectrum white LEDs (like those in AeroGarden systems): follow the manufacturer's recommendation, usually 2–4 inches
• T5 fluorescent tubes: 2–3 inches

The plants are stretching toward the light because they're trying to find more of it. The stem elongation is a survival response, not a sign of health.

The 24-hour light issue

Running 24 hours of light is not ideal for most seedlings, but it's a secondary issue compared to intensity:

• Most plants benefit from a dark period for respiration, phloem loading, and hormonal regulation
• 24-hour light can cause mild stress (leaf curl, reduced chlorophyll efficiency) in some species
• 18 hours on / 6 hours off is a better seedling schedule
• However: a seedling 3 inches below an adequate light for 18 hours will be far more compact than a seedling 8 inches below the same light for 24 hours

Fix the distance first, then reduce to 18-hour cycles.

Practical fixes

Immediately: Lower your light to 3–5 inches above the seedling tray. Watch for any heat stress (leaves wilting, white patches) and back off slightly if you see it - but most LED panels at this distance produce negligible heat.

Support falling seedlings: Use a toothpick or bamboo skewer to prop stems upright. Stems will thicken as they receive more light.

Bury the stem slightly if transplanting: When moving seedlings to your hydroponic net pots, bury the stem a bit deeper than it was. This stabilizes leggy seedlings and the buried section will sometimes develop additional root structure.

Add airflow: A small fan directed gently at seedlings strengthens stems through a process called thigmomorphogenesis - mechanical stress from air movement stimulates thicker, stronger stem development.

What adequate light looks like

Healthy seedlings under correct light:

• Compact, short internodal spacing (nodes close together)
• Deep green color (not pale yellow-green)
• Thick stems that don't require staking
• Leaves that are wide and horizontal rather than narrow and angled upward

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This answer is reviewed against published horticultural research. It is not a substitute for advice from a certified horticulturalist.