Sediments remediated with a nature-based solution approach (NBS-sediments) can represent a suitable and affordable alternative to peat as a constituent of growing media for ornamental plant production based on the combination of advanced production efficiency and rational green use of resources, including peat and water. In a greenhouse experiment, the effect of different growing media containing NBS-remediated sediments on two-year-old container grown cherry laurel (Prunus laurocerasus cv. ‘Novìta’) under standard and induced restrictive irrigation was evaluated. Six ternary mixes with different proportion (45:30:25 and 30:20:50 v/v) of peat:pumice:sediment (PE:TS25, PE:TS50), coconut fiber:pumice:sediment (CF:TS25, CF:TS50) and wood fiber:pumice:sediment (WF:TS25, WF:TS50) were tested in comparison to the standard peat:pumice blend (60:40 v/v), commonly used for pot ornamental crops ad used as control (PE, control). Pots were drip irrigated with 200 and 250 cc daily water volume (DWV). Cherry laurels grown in the control showed the lowest sign of stress, maintaining the highest net CO2 assimilation and transpiration rates, however stomatal conductance was reduced compared to PE:TS mixes. On the other hand, photosynthetic performance was strongly depressed by WF:TS25 and WF:TS50 under reduced DWV compared to the control, due to the combined effect of physical properties of the used matrices and reduced water availability. Nevertheless, final biomass production of plants grown on sediment-based growing media was similar to that of control, indicating that photosynthetic performance of plants fully recovered during the cultivation period. Differences in final plant development were negligible when compared to quality standards of marketing categories. Thus, appropriately blended NBS-sediment-based growing media can be used on a larger scale to produce rustic outdoor ornamentals.

The aim of this research was to assess the quality attributes of the fruits of wild strawberry (Fragaria vesca) “Regina delle Valli” plants cultivated in pots in remediated-sediment-based growing media (GM). For this purpose, phytoremediated and landfarmed dredged sediment from Leghorn Harbor (Italy) was mixed into a peat-based commercial substrate at different volume/volume percentages (0, 50 and 100%), and the plants were grown under greenhouse conditions with two different water regimes (WR1 = 950 cc/day; WR2 = 530 cc/day). The fruit quality parameters were differentially affected by the main factors (GM and WR) and their combinations. The fruits obtained from the substrate richest in treated sediment and with the higher water regime (TS100-WR1) showed the highest content of sugars (4056, 5256 and 5178 mg/100 g FW of sucrose, glucose and fructose, respectively), total soluble solids (16 °Brix) and organic acids (30, 490 and 2300 mg/100 g FW of ascorbic, malic and citric acid, respectively). Neither the polyphenol content nor the DPPH radical scavenging activity were significantly affected by the treatments, although the TS100-WR1 plants showed the highest DPPH value (an inhibition of 0.71%). Among the analyzed organic contaminants, only total heavy hydrocarbons (C10–C40) were found in fruits from TS50 and TS100 at very low values, while heavy metals were not detected. The PCA statistical multivariate analysis performed on the visual, olfactory, chewing and tasting aspects of a sensorial evaluation clearly showed that the substrate’s chemical–physical properties exerted a relevant influence on the fruit samples, while the irrigation regimes did not affect significantly fruit quality parameters. A number of highly correlated soil/fruit parameters were found. The remediated sediment proved to be a valid alternative to peat for wild strawberry production, even at the highest concentration.

Climate change is causing a decline in the availability of crucial resources such as water and fertile soil, leading to a detrimental impact on crop yields. Basil (Ocimum basilicum L.), an annual aromatic plant used worldwide for culinary, cosmetic, and medicinal purposes, is especially at risk due to its high water demand and specific growing requirements typical of the Mediterranean climate. In Italy, basil is an essential part of any herb garden and is also commonly found in households as a potted plant. Nowadays, the conventional practice of growing basil in pots with peat as the primary medium is not environmentally sustainable, which underscores the need for alternative and sustainable cultivation techniques to ensure the continued growth of this majestic king of herbs. A greenhouse factorial experiment was conducted to study the impact of peat replacement and reduced water supply on the growth and biochemical traits of basil plants. The study included two cultivars (‘Genovese’ and ‘Valentino’), three substrate mixes with phytoremediated dredged sediment (TS) at varying volume percentages (0%, 12.5%, and 25%), and three levels of water irrigation (normal, reduced by 25%, and reduced by 37.8%). Increasing the TS percentage resulted in higher germination rates and greater biomass production in both cultivars compared with the control. ‘Valentino’ potted plants produced a higher yield than those of ‘Genovese’, while the latter had higher pigment contents due to its genetic characteristics. All combinations of substrates mixed with the highest water amounts of irrigation positively impacted seed germination and biomass-based outputs, while control peat with reduced water availability led to lower plant yields and germination capacity. Substrates with TS had suitable physicochemical characteristics for plant development. Our findings suggest that using peat–TS mixtures can produce quality results comparable to or even better than conventional soilless culture using only peat. Thus, replacing peat with moderate percentages of TS can be an effective and sustainable practice for recycling phytoremediated sediments.

Carried out within the LIFE17ENV/IT/000347-SUBSED project, this research aimed at investigating the effect of a treated sediment (TS) as substrate component on the quality and marketability of three widespread containerized ornamental species: cherry laurel (Prunus laurocerasus) cv. Novìta, calla lily (Zantedeschia aethiopica) and protea (Protea cynaroides) cv. Little Prince. The TS was mixed with soilless substrates as sphagnum peat, coir, and bark in different proportion (0%, 25% and 50%). In cherry laurel, the TS used in 25 - 50% proportions reduced plant height, slightly altering its attractive vibrant foliage. A positive effect of the TS was evidenced on calla lily, where both tested sediment-based mixtures allowed a copious blooming and flower quality raised as the sediment content increased (TS 50% > TS 25% > TS 0%). Post-harvest longevity and colour of flowers were not affected by substrate composition. The effect of sediment-based substrates on protea growth and blooming showed an opposite trend (TS 0% > TS 25% > TS 50%), with plants grown on 50% v/v TS exhibiting a considerable reduction in plant growth and production of flower clusters, with brighter tones turning towards purple. Based on sale values, the TS proved to be a sustainable alternative for the production of potted ornamentals if properly mixed with other organic matrixes, such as peat and coir.