Seedling SOS: What's Wrong With My Seedlings (And How to Fix It)
Something's gone wrong and you want a quick answer. This guide is designed for exactly that — find what you're seeing in the table below, identify the likely cause, and follow the fix.
The most important thing to know before you start: almost every seedling problem is environmental. It's rarely the seed. The conditions around the seed — moisture, light, temperature, drainage — are what cause most issues, and adjusting those conditions is almost always the solution.
💡 Before you do anything
Don't panic and don't over-intervene. The most common mistake when something looks wrong is reaching for more water, more fertiliser, or moving things around repeatedly. Pick one likely cause, make one change, and give it two to three days before reassessing.
Quick Diagnosis: Find Your Problem
Find what you're seeing in the left column. The likely cause and fix are in the columns to the right. The last column links to the relevant guide for more detail.
| What You See | Likely Cause | What to Do | Read More |
|---|---|---|---|
| Nothing germinated | Soil too cold, planted too deep, or too dry/wet | Check the season, sow slightly shallower, keep mix consistently moist — not soaked | Timing · Watering |
| Patchy germination — some up, some not | Uneven moisture or natural seed variation | Wait a few more days before resowing — late germination is normal | Watering |
| Seedlings falling over at soil line | Overwatering or damping off (fungal) | Let the surface dry slightly, improve airflow, remove affected seedlings immediately | Watering |
| Tall, thin, stretched stems | Not enough light | Move to a position with stronger morning sun immediately | Sunlight |
| Seedlings leaning to one side | Light coming from one direction only | Rotate trays daily or move outdoors | Sunlight |
| Pale green or yellowing leaves | Overwatering, poor drainage, or light too weak | Check drainage holes, reduce watering, move to brighter position | Watering · Sunlight |
| Leaves scorched or crispy at edges | Too much harsh sun too quickly | Move to shade, reduce midday sun, reintroduce gradually | Sunlight |
| Wilting despite moist soil | Overwatering, root rot, or transplant shock | Stop watering, check roots, move to shade if recently transplanted | Watering · Transplanting |
| Slow or stopped growth | Cold soil, low light, overcrowding, or overwatering | Check season timing, improve light, thin if crowded, reduce watering | Timing · Sunlight |
| Seedlings wilted after transplanting | Transplant shock | Move to shade, keep moist, don't fertilise — give it 2–3 days | Transplanting |
| Mould on soil surface | Overwatering and poor airflow | Reduce watering frequency, improve ventilation, scrape off visible mould | Watering |
| Seeds washed to one side or buried too deep | Heavy watering after sowing | Water mix before sowing, not after — use a gentle mist on the surface | Watering |
The Three Most Common Problems — In More Detail
Most seedling problems fall into one of three categories. Here's a bit more context on each.
Nothing germinated
The most disheartening outcome — and almost always fixable. Seeds are more resilient than they look, but they need the right conditions to break dormancy. The most common reasons nothing comes up: soil was too cold (especially warm season crops sown too early in spring), seeds were buried too deep, or the mix dried out completely at some point after sowing.
Check your timing against a planting calendar for your region. Re-sow slightly shallower than before. Keep the mix consistently moist — not soaked — and cover the tray to hold moisture in. Most seeds will germinate within one to three weeks in the right conditions.
When to Plant Seeds in Australia: A Practical Guide
Leggy seedlings — tall, thin, stretched stems
Leggy seedlings are almost always a light problem. The seedling is stretching upward trying to reach a stronger light source than it currently has. It's one of the most common issues for beginners starting seeds indoors or on windowsills.
The fix is to move them to stronger light — specifically, more direct morning sun — as soon as possible. The stretched stems won't shorten, but new growth from that point will be sturdier. For seedlings already quite leggy, a gentle stake or support can help while they recover.
How Much Sunlight Do Seeds Need to Grow?
Seedlings falling over at soil level
This is usually damping off — a fungal condition caused by excess moisture and poor airflow. The stem appears pinched or rotted at the base and the seedling collapses, often overnight. It can spread quickly through a tray.
There's no cure once it takes hold in a seedling. Remove affected plants immediately to stop it spreading. For the rest of the tray: stop watering, improve airflow, and let the surface of the mix dry slightly between waterings. Prevention is the real answer — good drainage, not overwatering, and not keeping seedlings in still, enclosed conditions.
How to Water Seeds and Seedlings Without Killing Them
When to Start Again
Sometimes the right call is to start over rather than nurse struggling seedlings. A few signals that starting fresh is the better option:
The entire tray has damped off. Seeds didn't germinate at all after three weeks in the right conditions. Seedlings are so leggy they can't support themselves and won't recover. The growing season is still early enough that a fresh start will produce better results than trying to save what's there.
Starting again isn't failure — it's part of growing. Even experienced gardeners lose trays. Seeds are inexpensive, the growing season usually has room for another attempt, and a fresh start with the right conditions nearly always outperforms trying to rescue plants that got off to a bad start.
💡 One more thingKeep a note of what went wrong and when. A single season of paying attention to what worked and what didn't is worth more than any amount of reading. Most gardeners who stick with it find that their second season is dramatically easier than their first. |
Go Deeper: The Full Guides
Each problem in the table above is covered in full detail in one of the guides below. If you want to understand the cause rather than just fix the symptom, these are worth reading.
What to Plant Seeds In (And What to Avoid)
Choosing the Right Container for Planting Seeds
How to Water Seeds and Seedlings Without Killing Them
How Much Sunlight Do Seeds Need to Grow?
When to Plant Seeds in Australia: A Practical Guide
Transplanting Seedlings: When to Move Them and How to Do It Without Shock
Or start from the beginning:
Growing from Seed: A Complete Beginner's Guide
