Knowing your roots...
It has been about 3 weeks from starting my seeds and they are growing so fast. Even with the warm weather, it is too early in the season of Wisconsin to transplant in the soil with the risk of frost. So what do you do when your baby plants have out grown there seed trays, but the weather is too risky? Pot Up
Why Pot Up?
The main purpose of to prevent stunted root growth. With out room for the roots to grow they will just circle around in the container and stunt the plants growth when you transplant them into the ground. This also give the plant more dirt to absorb nutrient. As well as allow you offset any leggy/spindling seeds that have too long of a stem by to set the plant deep into the pot and filling up soil around the stem.
When to Pot Up?
Usually the best time is after you see true leaves and they are about 3-4 inches tall. Those first 2 leaves are just baby seed leaves called 'cotyledon leaves'. It is also a good time when you see roots grow out of the bottom of the tray or pot For most plants it is about 3 weeks. Peppers are known to take longer.
How to Pot Up?
Water the plants the day before potting up, this will help loosen the soil. Choose a pot or container that has proper drainage and is 2 inches or bigger. Get some fresh garden potting soil. The day of potting up, i like to loosen the sides of soil in the seed tray with a butter knife. Put a small layer of soil in the pot/container you will be using. When removing try not to touch or damage the stem or the true leaves, try to pull using the cotyledon leaves and turning the seed tray upside down. Put the plant in the pot and fill with soil.
You still need to water and provide additional light for your plants. You might even want to start 'hardening off' you plants by setting them out side in the day. They are still baby plants, so don't leave them out if it gets bellow 65F at night or if it is raining (risk of over watering you plants).