Why are my seedlings falling over?
Seedlings collapsing at the soil line is almost always damping off, a fungal disease that attacks stems in wet, poorly ventilated conditions.
Damping off looks alarming because it happens fast. A tray of healthy seedlings can be mostly gone in 48 hours. The sign is a ring of stems pinched off at the soil surface — they fall over without any visible lesion above ground. The rot is happening where the stem meets the mix, and by the time a seedling falls, the damage is done.
The organisms responsible — primarily Pythium, Rhizoctonia, and Fusarium species — are common in garden soil and even in some commercial potting mixes. They spread through water and thrive in wet, warm, still air. Using sterile seed-starting mix (not garden soil or compost) and not reusing old mix from a previous damp-off episode removes their foothold.
Prevention is more reliable than treatment once it starts. Use sterile mix, fill trays only to about a half-inch below the rim so airflow can move across the surface, water from the bottom when possible (set trays in water until the surface looks damp, then drain), and run a small fan on low near your seedlings. Good airflow drops humidity at the stem level and is one of the most effective controls available.
If only part of a tray is affected, remove the collapsed seedlings immediately, let the surface dry out, and move the tray somewhere with better airflow. Remaining seedlings may survive if conditions improve quickly. Hydrogen peroxide diluted 1:4 with water as a drench can help slow further spread, though it won't reverse damage already done.
- TomatoThe warm-season anchor of the summer garden.
- PepperA tropical perennial grown as an annual — patient, slow, and particular about warmth.
- BasilThe summer companion — to tomatoes, to pasta, and to the gardener with a south-facing window.
- LettuceA cool-season leaf crop that thrives in spring and fall, sulks in summer heat.
- KaleThe cold-weather workhorse that improves when everything else quits.
- AnthracnoseSunken, dark circular lesions on ripening fruit, sometimes with salmon-colored spores in the center.
- Bacterial WiltCucurbit vines wilt rapidly despite moisture; cut stem shows sticky ooze that threads when pulled apart.
- Bird DamageBerries pecked or missing, seeds scratched from beds, and seedlings dislodged — birds feeding on ripe fruit, seeds, or soil grubs.
- Black RotV-shaped yellow lesions at brassica leaf margins with blackened veins inside — a bacterial disease that moves through the vascular system.
- Gray Mold (Botrytis)Gray-brown fuzzy mold on fruit, flowers, or stems — soft, collapsing tissue beneath the coating in cool, wet conditions.
- Why aren't my seeds germinating?Cold soil is the most common culprit — most vegetable seeds stall below 60°F, and old or improperly stored seed may not be viable at all.
- Why are my seedlings tall, pale, and floppy?Seedlings stretch toward inadequate light — the fix is moving them closer to the light source, not giving them more hours of light.
- My transplants look wilted and sad after planting — is this normal?Some wilting and leaf drop in the first few days after transplanting is normal; if a plant is still wilting after a week and well-watered, the roots may have been damaged.