Environment Feeding and water Lifecycle Seedling
The seedling stage: weeks 1 to 3
Seedlings need gentle light, warmth, moderate humidity and very small drinks of water. The most common mistake is giving a tiny plant a big pot's worth of water.
On this page
The seedling stage starts when the first leaves open and lasts until the plant has several sets of true leaves.
What seedlings like
- Light: gentle, not intense. Keep it close enough that the plant doesn’t stretch, but not so strong that it bleaches.
- Warmth: comfortable room temperatures, roughly the mid to upper 70s Fahrenheit.
- Humidity: a little higher than for adult plants. Dry air can twist the first leaves.
- Water: small amounts near the stem, spreading outward as the plant grows.
Watering a seedling in a big pot
Water for the roots, not the pot. Start with evenly pre-moistened, well-drained medium. In an oversized pot, size each watering to the small root system instead of saturating the whole pot again and again. Keep enough of the root zone moist and widen the watered area as roots grow. Don’t let coco or the root ball dry out hard.
Common problems
| You see | Likely cause | What to do |
|---|---|---|
| Tall, thin, floppy stem | Not enough light | Move the light closer or raise intensity; you can bury extra stem when transplanting |
| Stem pinched thin and brown at the soil line | Possible damping off from fungal or oomycete pathogens, often favored by wet conditions | Usually fatal; clean the tray and start again with drier media and better airflow |
| Pale, slow seedling | Cold or soggy roots, or no food in an inert medium | Let it dry a little, warm the roots, and feed gently if in coco |
| Twisted, burnt first leaves | Rich soil, dry air or direct wind | Check medium fertility, root-zone moisture, pH and airflow before changing the feed; don’t starve seedlings in unamended coco |
The table lists possibilities, not diagnoses you can make from looks alone. Timing and environmental ranges are starting points. Check the medium and recent changes before treating a symptom.
Sources (3)
- University of Minnesota Extension. Starting seeds indoors. https://extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors [Evidence access: EXTENSION TEXT VERIFIED.]
- Punja, Z. K., Collyer, D., Scott, C., Lung, S., Holmes, J., & Sutton, D. (2019). Pathogens and molds affecting production and quality of Cannabis sativa L. Frontiers in Plant Science, 10, 1120. https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01120/full [Evidence access: FULL TEXT VERIFIED.]
- University of Maryland Extension. Growing vegetables in containers and salad tables. https://extension.umd.edu/resource/growing-vegetables-containers-and-salad-tables [Evidence access: EXTENSION TEXT VERIFIED.]