Ask an adult to help choose a seedling station away from pets, busy walkways, heaters, cold drafts, and valuable surfaces. Use a waterproof tray and nearby clean water.
- Start with clean containers and sterile seed-starting mix, not garden soil that may carry damping-off organisms.
- Give seedlings strong light. A sunny window is often uneven; an adult-installed LED grow light a few inches above the leaves produces sturdier growth.
- Put electric lights, cords, timers, and fans where water cannot reach them. Use approved equipment and dry hands.
- Provide gentle air movement without blasting tender plants.
- Water from below or at the mix, then drain the tray. Constantly wet mix encourages root and stem disease.
- Begin dilute fertilizer only when seedlings have true leaves and the product label calls for it. An adult should mix and store it.
- Rotate trays, inspect daily, and remove a diseased seedling before trouble spreads.
Do not build a cold frame from old windows. Glass can break, old paint may contain lead, and a heavy lid can fall. Use a purpose-made, shatter-resistant cold frame or the supervised bottle cloche, and vent either one every sunny day.