I apologize, I know there are threads on this, but Search didn't find them... and I'm new to the growing game. I started my seeds 10-11 days ago, in a seed starter kit/tray. How do I know when they're ready to be transplanted into small pots? See pic. Thanks.
Since you said you were new to growing, my rule of thumb for transplants has always been wait until the leaves are as wide or wider than the outside of the old pot. When you take them out of the old pot, you should see exposed white, clean, healthy roots holding the potting soil in place.
I use root riot plugs in a plastic egg crate when starting seeds:
I keep the root plugs moist until I can see roots coming out of the sides of the plug, like this picture below:
The new pot should not be too large, I go from seedling in root riot plug > pint > quart > 1 gallon > 3 or 5 gallon fabric final pot. Each time you transplant, you are growing a larger, healthy root ball.
Also note the holes drilled into the sides of the pots, this allows maximum drainage and air to circulate around the roots. One of the reasons fabric pots work so well is because they allow water AND air to circulate thru the fabric, roots need oxygen to thrive. Finally, transplanting into gradually larger pots allows you to soak the pot each time you water, then allow the pot to dry before watering again. This also allows air to circulate thru the roots which helps the plant to maximize growth.
Have fun!