If they had no roots, then they weren't ready to transplant. To help, you need to provide a complete accounting of your seed starting process, including each step you take, how long they spend at each step, etc. Also include your zone, I don't think it's 16??

Yeah are you a California/Sunset 16 zone? Otherwise location would be a big help and as Sleepy said much more info.

Based on info so far it could be something as simple as lack of patience. ;) Once transplanted things don't just zoom off - they sit and pout for days. Did you use peat pellets or peat pots? If so did you strip off the pots and/or netting?

What is your soil temp running - not air, it's irrelevant - but soil? Next most likely source of your problems is too much water. Especially when you say things like "plenty of water". That's a red flag!

No one ever thinks that are watering too much - but they are.

Need more details please.

Dave

PS: Why would you be planting sunflowers and peas at the same time? They are very different season items.

Well, learn something new every day! I had no idea about these sunset zones. Lots of zone learning for me lately! :)

Yep many in the west use the Sunset zones instead as they are more specific to the various regions. Last I checked I think the zone numbers run up into the 30's - maybe more.

Dave

Here is a link that might be useful: Sunset Gardening Zones

I am perplexed this is the first time I recall reading about sunset zones. Looking at the website given I am in zone 41. I always wondered why I chose to wait till May 10th to really plant summer items and now I know.
This is something I will have to look into some more out of curiosity.