What to do this week: Cover cuttings and attack algae To persuade indoor jasmine (Jasminum polyanthum) to flower in the New Year, give it a fortnightly high-potash feed. Attack algae Sweep paths and keep them algae-free using a cleaner such as Jeyes Fluid, or Biotal Algae and Mould Stain Cleaner (from organiccatalogue.com). Cover cuttings Lively autumn growth of argyranthemums gets frosted, so take a few cuttings now and they will mark time all winter in a frost-free greenhouse.