No ma'am, not "very little rain". Absolutely zero rain. The planet had been stripped of nucleonic Acids which are integral to precipitation and life on ALL M Class planets. This was the debt that could never be repaid. Why Caretaker caretook. His people destroyed Ocampa, and for all their power and savvy they couldn't fix it. Maybe for the first few years they might have told the near by powers that Ocmapa was a no go area, and maybe they killed a few colonies that tried to build on the bones of the dead Ocampa in the Ocampan cities/ruins... But it had been a thousand years. Caretaker was tired. It didn't hurt the Ocampa and if he chased the Kazon away, someone else would just try to set down roots next month.