## 2 Materials and Methods  
### Growing Conditions and Experimental Protocol  
Research was carried out on rocket (_Diplotaxis temifolia_ L.--DC.) at the Department of Agricultural Sciences, University of Naples Federico II, Portici (Naples), Italy, in 2022 and 2023. The crops were grown under a greenhouse covered with a polyethylene film, in sandy loam soil (75.5% sand, 17.2% silt, 7.3% clay), with a pH of 6.7 and an electrical conductivity of 512 mS cm\({}^{-1}\). During the cropping seasons, the mean monthly temperatures under the greenhouse were 13.3 \({}^{\circ}\)C in October, 10.5 \({}^{\circ}\)C in November, 6.6 \({}^{\circ}\)C in December, 5.1 \({}^{\circ}\)C in January, 6.8 \({}^{\circ}\)C in February, and 12.2 \({}^{\circ}\)C in March, in 2022; 13.0 \({}^{\circ}\)C in October, 10.1 \({}^{\circ}\)C in November, 6.9 \({}^{\circ}\)C in December, 5.4 \({}^{\circ}\)C in January, 6.6 \({}^{\circ}\)C in February, and 12.5 \({}^{\circ}\)C in March, in 2023.  
The experimental protocol was based on the factorial combination between five perennial wall rocket cultivars (Mars, Naples, Tricia, Venice, and Olivetta), three biostimulant formulations (the algae _Cystoseria tamariscifolia_ extract; the protein hydrolysate, Dynamic, by Hydro Fert, Barletta, Italy; the microalgae _Spirulina platensis_ extract (Micoperi Blue Growth, Ortona, Chieti, Italy)), plus an untreated control, and three crop cycles (autumn, autumn-winter, and winter). The extracts were prepared as follows: For _Cystoseira tamariscifolia_, the thalli were harvested and then dehydrated to be finely ground; at each preparation, the powder was added to osmosis water, shaken in the dark for 24 h, and used in nebulization. For spirulina extract, the powder was added to osmosis water at each treatment, shaken for 24 h, and used in nebulization.  
The five commercial wall rocket cultivars have the following characteristics: Olivetta (La Semiorto Sementi, Sarno, Italy) has smooth olive-shaped leaves and rapid 20-25 day maturation; Tricia ([PERSON], Tarquinia, Italy) features large serrated leaves, fast growth, and downny mildew resistance; Venice and Naples (Levantia Seed, Porto Viro, Italy) have high leaf serration and strong Fusarium resistance; and Marte (Seedium/Blumen Vegetable Seeds, Milan, Italy) is characterized by erect growth habit and long shelf life. The treatments were arranged in the field using a split plot design with three replicates and the experimental unit covered a 4 m\({}^{2}\) (2 \(\times\) 2 m) surface area, with 4000 plants. The biostimulants were foliarly applied by spraying a 15 L solution ha\({}^{-1}\) at the concentration of 3 g L\({}^{-1}\) for _Cystoseira tamariscifolia_ and _Spirulina platensis_, or 3 mL L\({}^{-1}\) for the protein hydrolysate, three times in each crop cycle at 7-day intervals, starting when the leaves were 2-3 cm long.  
The sowing (4 kg of seeds per hectare) was performed on 14 and 13 October in 2022 and 2023, respectively, with 2 cm spacing along the rows which were 5 cm apart. Crop management was performed using sustainable practices, including an organic pre-seeding fertilization with N, P\({}_{2}\)O\({}_{5}\), and K\({}_{2}\)O (at a rate of 38, 10, and 30 kg ha\({}^{-1}\), respectively), and control of pathogens and pests with copper oxychloride and azadirachtin treatments, respectively. During the three growing seasons, drip irrigation was activated when the soil available water at 10 cm depth dropped to 80%, and N, P\({}_{2}\)O\({}_{5}\), and K\({}_{2}\)O were supplied by fertigation in each crop cycle at a dose of 112, 30, and 90 kg ha\({}^{-1}\), respectively. The leaves were harvested when commercially ready (7 to 10 cm long) at 2-5 cm above soil surface. The harvests were conducted on 24 and 22 November, 10 January, and 8 and 10 March, respectively, in 2022 and 2023.