Good news: A volunteer plant is always cool, and a welcome surprise. Bad news: Cauliflower is high maintenance. It doesnt take kindly to neglect. Protect it the best you can, give it plenty of water, and shield the sun from the crown when it starts forming. Good luck! :-)

thisisme, do you mean no seeds are germinating in the pile itself, or after you spread it? I'm quite possibly missing something in your post, but just want to clarify! Some seed doesn't germinate in 'fresh' compost, but squash loves growing in my compost heap... I don't think high ratios of carbon should interfere with germination; it'll break down slowly, but it will still break down. I'd rather have a slow, carbon-heavy pile than risk a stinky, ammonia off-gassing monster that makes the neighbours think compost's gross.

I hate to spoil the fun, really I do, but there is a very good reason not to use volunteer seedlings. They can carry or encourage diseases, specifically viruses, that have no effective controls. I have personal experience with this and went for years without being able to grow any type of squash because I had a virus in my soil. All I could do is wait and hope it went away. Eventually, I established a new bed and have been careful not to transfer soil from the contaminated beds into it and I have my zucchini and pumpkins once again. Most likely the virus came from a volunteer seedling that I let grow in the bed that then became contaminated. But don't take my word for it ... For tomatoes: "Destruction of volunteer plants is an important practice in the control of several diseases, because it prevents large populations of pathogens from surviving from one cop to another. Crop rotation also works to prevent crop to crop survival of specific tomato pathogens." https://edis.ifas.ufl.edu/vh056 And for the squash family: "Destroy volunteer cucurbit plants. These can harbor cucurbit disease organisms." http://www.ag.ndsu.edu/pubs/plantsci/hortcrop/pp656w.htm

ltog: I would guess a certified organic entrepenuer could be trusted that the calculations to arrive at ph balancing and correct ratio of NPK are correct and will remain that way after being sealed up and shipped around in varying temps. My point is why would you use it. You could probably build your soil cheaper using the same properties. Correctly composted browns and greens are truly organic in Nature and do not need additions............but I digress. I would do nothing more, let them grow on thier own for right now...... Once the soil has dried out totally----- to where you poke the soil w/ your finger down two knuckles.........drench w/ fish emulsion and seaweed extract.. at least a gallon of combined, diluted medicen per plant............ Find a source of compost containing ONLY heat treated greens and browns...........buy a soil test kit for PH and NPK. The soil in your garden and the compost you add to it should be between 6-7 PH and off the charts in NPK...... Cover the soil around your plants (4 ft diameter) with as much of the compost as you can obtain,..... right up around the stems of the tomatoes as far as you like. Preferrably before the drench. Mulch with anything you can that will cool the root zone, keep out weeds and prevent the plant from any contact with the soil, including splash back. Compost is not the same nor does it afford the benefits of a good mulch. There you Go ;) Hope I helped, Tom