When is it time to thin seedlings?

This is my first year starting things from seed and it seems to be going well. I planted 2-3 seeds in each peat pot and I have 2-3 seedlings in each one. When should I start thining?

Also on tiny plants like marjoram should I just leave all the little seedings?

What variety of plants did you sow in the peatpots? And, what size pot are the in, in diameter? How large are the plants?

I ask because they can be dug up carefully and replanted in another to give you 3 plants from one pot. There are some plants that don't transplant well.

Since the pots are peat, you can carefully break it apart and divide it so that each plant have its own set of roots, or trace the plant's roots down. I have done this many times.

If you prefer to thin, leave the strongest growing one when 2 true sets of leaves have developed, or just remove one, later remove the second one. You want to make sure that you have one left that is healthy and will continue to grow.

When I thin out plants, I use a small scissor, embroidery type, and just snip the stem at ground level. Sometimes if it is pulled out, it can disturb the roots of the remaining plants.

Thank you for the great advice. I am starting herbs, tomatoes, peppers and flowers. I am surprised by my success so far. I will just keep babying them until it is time to thin then maybe transplant as you suggested.