This is Bob (and not the lizard sort of Bob.)

Check your plants roots before you try to put them in soil. If the roots are smooth they won't survive being transplanted into soil. The roots need to have little hairs on them (or nubs that can become root hairs quickly) to survive in soil. Hydroponically grown plans have totally smooth roots mainly because they don't have to work to get their water, they are bathed it in.

If you're going to transplant cuttings like the green onion or celery your best bet is to get it into the soil within a few days rather then letting it sit in water for a long time. Leaving it sitting in water it will either develope hydroponic type roots or it will use up all the available nutrients and die.

I keep meaning to try this with celery, thanks for the reminder :) Do you have to put it in soil or will it grow enough just in water?

Oh, and my sister and I used to call a lot of things Bob-Fred when we were kids :)

will you do a post on how to grow your own celery? I had no idea you could! Given that it's high pesticide if not organic, this would be very fun/money saving

I have two of these in my kitchen window now and some potted in dirt! I had a couple of celery failures over the summer and I think my problem was over-watering and poor drainage. I change the water the celery is in every couple of days. The roots take a while to grow sometimes. Last time I waited until I had some really good roots (and this time it was celery from a local farm that came into the food bank, so the bottom was kind of knobbly and not smooth like the stuff that comes from the grocery store--we cut the celery and bag it, so I got to take the ends home). I planted it in a pot with better drainage and it's living in my bedroom window. I do not water it too often and so far, so good! I have been snipping some off to use in tuna and in various other things. Someone mentioned scallions--I just cut them, leaving about an inch above the root and I stick them directly in dirt. They just keep growing and growing and I snip them off as needed.

My celery was fine until I planted it in the dirt too, then it just died. I have two green onion bottoms in water right now in the windowsill trying to get them to regenerate. This time I left three inches of onion on the top portion and just used the ends for salad last night. Fingers crossed it will work this time.