Last few - these might help me complete the puzzle.
27a To produce a larger harvest, perhaps, a sudden occurrence (7) O?T????
29a Not the first show of colour spread out about one (9) R?D?S????
n., v. -cropped, -crop•ping. n.
1.
a. a cropping out, as of a stratum or vein at the surface of the earth.
b. the exposed portion of such a stratum or vein.
2. something that emerges suddenly or violently in the manner of an outcrop; outbreak.