BackgroundClary sage (Salvia sclarea L.) has anti-inflammatory and anti-microbial properties; its seeds were imported from Germany for cultivation and acclimatization under the Egyptian environmental conditions as a new source of natural products. Solutions of alga and banana peel waste considered as a source of plant nutrition; it contains some bio-regulators and minerals. This research paper aimed to evaluate growth (fresh and dry weights) and chemical composition (free radical-scavenging activity, carbohydrates, flavonoids, phenols and phenolic compounds) under foliar spray of algae solution (ALS) and the extract of banana peel waste (BPW).ResultsThe highest values of fresh and dry weights were detected with the treatment of 1.5 g/l (BPW) × 1.5 g/l (ALS). The maximum inhibition of free radical -cavenging activity was recorded at 1 g/l (ALS) × 0.5 g/l (BPW). 2 g/l (ALS) without BPW treatment resulted in the greatest amounts of total carbohydrates. The greatest accumulation of total flavonoids was obtained from the plants treated with 0.5 g/l (BPW) × 1 g/l (ALS). Plants exposed to 1.5 g/l (BPW) with 2 g/l (ALS) gave the greatest accumulation of total phenols. Phenolic compounds that were detected by HPLC analysis were changed due to ALS, BPW, and their interactions.ConclusionDifferent variations were observed in growth characters and various chemical constituents of Clary sage under the application of ALS and/or BPW. This research will help farmers to produce medicinal and aromatic plants by using cheap and environmentally friendly methods.