Right after seeds sprout indoors, you need to make three quick changes to keep them alive and growing strong. Remove your humidity covers, lower the room temperature, and move your grow lights closer to the tray. This seedling care after germination phase sets up your plants for success or failure in the weeks ahead.
I lost my first batch of tomato seedlings to damping off because I left the dome on too long. The fungus spread through all 48 cells in just two days and killed every single plant. Now I remove covers the moment I see green poking through the soil surface. Fresh air circulation stops that disease before it can take hold.
My neighbor made the same mistake last spring with her pepper starts. She kept the dome on for a full week after sprouting because she thought they still needed the humidity. Every single seedling fell over at the soil line within three days after that. The stems had rotted from too much moisture trapped under the plastic cover.
You need to change your room temperature once seedlings emerge from the soil. Seeds like warmth around 75 to 85°F (24 to 29°C) to sprout fast. But those temperatures make seedlings weak and leggy after they come up. Drop your room to 60 to 70°F (15 to 21°C) for stocky stems that hold up well.
Your grow lights need to sit much closer to seedlings than most people think at first. UMN Extension says 2 to 4 inches (5 to 10 centimeters) above the tops works best for growth. Raise the lights as your plants grow taller each week. Run them for 14 to 16 hours each day to give seedlings the energy they need.
Your post germination seedling care follows a simple week-long plan. Day one after sprouting you remove the dome and add air flow. Days two through three you lower lights and reduce heat in the room. By day seven most seedlings show their first true leaves and you can start feeding with diluted fertilizer at quarter strength.
Watch your seedlings each day during this critical first week of growth in your setup at home. Look for yellowing leaves that signal hunger or light problems. Check for wilting that means you waited too long between waterings. Catch issues early and your seedlings will bounce back fast before any real damage can set in to their growth.
Read the full article: When to Start Seeds Indoors: Ultimate Guide
