One room had four cannabis stalks planted, and the other had 12 healthy cannabis plants, ranging from 60 to 70cm high.
Alabaster told police he built the grow rooms two years ago and grew the drugs for his own use.
Yesterday he appeared in front of Judge Dugald Matheson in the Wanganui District Court and pleaded guilty to possession of cannabis, cultivating cannabis, possession of utensils for methamphetamine and theft of electricity.
Alabaster's counsel, Mark Bullock, said Alabaster had long-standing problems with drugs and hadn't been in trouble for a drug-related offence before, nor had he appeared in court since 2003.
Mr Bullock said Alabaster told police he had two growing periods of 10 weeks but the reparation was sought based on electricity usage of 18 hours a day for two years.
He wasn't using it that often but accepted he was stealing electricity and didn't want to draw out the process with arguments.
Judge Matheson called the offending "substantial", and said Alabaster had a drug problem that needed to be addressed.
He convicted him on all four charges and ordered him to pay the full reparation amount of $12,101, complete 200 hours of community work and nine months' supervision with the special condition he undergo a drug programme.
He ordered drug-related items found in the search destroyed.