I start mine in a 144 cell tray and move them into the 72 as soon as they come up then i leave them in the 72's until they get thier 4th set of true leaves (usually) unless the roots start coming out of the bottom then I put them in 4in. pots until it is time to put in garden.

Dale

I start my seeds in rockwool cubes they are clean & germination rate is great after plants start growing about 1" I then transplant them in pots until the last frost has gone. I take them out into the garage or out side shade to adjust to heat to prevent any shock the best time to plant into garden is after threat of frost has passed. It is easiest to plant right after it rains.I then plant them in the garden.At that time they are a good size & will grow fast, I also put around each plant dehydrated cow manure & water plants well. And then I put bamboo stick to hold each plant up.

I start my seeds in the 72 cell trays. When they are up to 2 leaves, I pot them up - usually in 6 or 8 oz styrofoam cups WITH DRAIN HOLES poked in the bottom. Or you can use small plastic pots. I have had terrible results with pepper seedlings in Jiffy Peat Pots. They don't drain well enough, and the seedlings rot away as a result of "wet feet."
John A