Air Plant Fertilizer Spray Diy . If dried blood in the mixture gets settled at the base, give it a good shake before applying. Fertilize once a month in addition to weekly waterings. Air Plant Fertilizer Spray Air Plant Tillandsia Plant Food Etsy from www.etsy.com Chop up the leaves in a bucket, cover them with rainwater and wait a month. You can end up with a burned plant if you feed them with undiluted fertilizer. Fertilize air plants once a month as part of their regular irrigation to promote healthy.