Cauliflowers growing well under enviromesh

Lots of growth in the allotment (including weeds!) at present. This is the cauliflower bed covered with a floating mulch of enviromesh (held down by four wooden planks) which has about eight caulis plus onions in between them, and a pic of one of the young caulis which looks pretty firm and is about 4 inches across. I was surprised to see this as I had dug this bed over in spring and sometimes the books say the bed needs to be firm and that you should only have dug it in the previous autumn otherwise you get loose heads. But I had put lots of well rotted horse manure in this bed and that, combined with the enviromesh protection, must have done the trick. My other cauli bed which was not dug over but did not have much organic matter in it is not doing so well. So there's a lesson for me - "cauliflowers need lots of manure, and this is more important than being in undug, firm ground".