Is it possisble your plants aren't getting enough sun? Portulaca wants all day sun, and it shouldn't be leggy. I can't imagine any other reason that seed grown plants would be leggy. Unless the original plants were hybrids, the seed grown plants should be just like the parents. Hybrids produce a mixture of seed reflecting the hybrid's original parents. But still...a leggy portulaca? Sounds like growing conditions.

Nursery grown annuals - and other plants - are grown under ideal conditions; something many of us cannot duplicate at home. Once you get them in the ground, they will likely begin to look like they're supposed to.

Yes, I don't think that they get enough sun. There is afternoon shade where they are. Thats' probably why.

They like lots of sun and can take the heat. They will reseed themselves and bloom, all in one year.

The problem I have with mine, is that the stems keep breaking off, or chewed off. I think squirrels may be doing it, or birds, since one I have growing next to my patio is fine. Weird.

If you are finding portulaca pieces, just stick them in some soil and they will root. More plants!