README file # FAIR Dataset — Data collection on different DLI and crops in Nära Dataset title: "Data collection on different DLI and crops in Nära" Dataset Author: Riccardo Prandi (Distal, University of Bologna), ORCID 0009-0002-4114-8311; Laura Carotti (Distal, University of Bologna), ORCID 0000-0003-0022-0057; Giuseppina Pennisi (Distal, University of Bologna), ORCID 0000-0001-9377-4811; Michael Martin (IVL, Swedish Environmental Research Institute; Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology), ORCID 0000-0003-3014-8930; Giorgio Gianquinto (Distal, University of Bologna), ORCID 0000-0002-6548-5526; Francesco Orsini (Distal, University of Bologna), ORCID 0000-0001-6956-7054 Dataset Contact Person: Giuseppina Pennisi (Distal, University of Bologna), ORCID 0000-0001-9377-4811, giuseppina.pennisi@unibo.it Publication Year: 2026 Funding statement: This study received funding from the European Union Next-GenerationEU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022). This paper is (partially) supported by the PRIMA program under grant agreement No 2242, project FrontAg Nexus. The PRIMA program is supported by the European Union. This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them. Dataset License: this data set is distributed under a Creative Commons Attribution-4.0 International (CC BY-4.0) license (https://creativecommons.org/licenses/by/4.0/) Dataset Contents The data set consists of: • 1 quantitative data file saved in .csv format "Database_NaraDLI.csv" • 1 README file saved in .txt format "Prandietal_NaraDLI_README.txt" ## Dataset documentation #Abstract This dataset presents experimental data collected to evaluate the effects of different combinations of photoperiod and light intensity, applied at a constant daily light integral (DLI, 9.75 ± 0.15 mol m⁻² d⁻¹), on plant growth, morphology, yield, and resource use efficiency in a commercial vertical farming system. The experiment was conducted at Nära Sverige AB, a commercial vertical farm located in Stockholm, Sweden, and included four leafy vegetable crops: crispy lettuce (Lactuca sativa L.), canasta lettuce (Lactuca sativa L.), pak choi (Brassica rapa L.), and green kale (Brassica oleracea L.). Three lighting regimes were compared: 14 h d⁻¹ at 190 µmol m⁻² s⁻¹ (14/190), 18 h d⁻¹ at 150 µmol m⁻² s⁻¹ (18/150), and 24 h d⁻¹ at 115 µmol m⁻² s⁻¹ (24/115). At harvest (31 days after sowing), destructive measurements were performed to assess morphological and growth-related parameters, including plant height, leaf number, leaf length, leaf width, leaf area, fresh weight, and dry weight. Light use efficiency (LUE) and lighting energy use efficiency (L-EUE) were calculated to quantify crop productivity relative to light input and electrical energy consumption. Results showed species-specific responses: continuous light (24/115) improved plant height and L-EUE in lettuce varieties, while pak choi exhibited higher leaf width and LUE under shorter, more intense light exposure. Overall, this dataset provides a comprehensive quantitative foundation to assess how photoperiod and light intensity combinations at constant DLI shape plant architecture, yield, and energy use efficiency across commercially relevant leafy vegetable species. --- # Methodologies ## Experimental Overview This dataset originates from a controlled-environment experiment conducted at Nära Sverige AB, a commercial vertical farm located in Stockholm, Sweden. The trial ran from seed sowing to harvest at 31 days after sowing (DAS). Four leafy vegetable crops were included: crispy lettuce (Lactuca sativa L. var. Danstar, Nunhems, ID, USA), canasta lettuce (Lactuca sativa L. var. Canasta, Florsilva Ansaloni, Bologna, Italy), pak choi (Brassica rapa L. var. Purple rain, CN Seeds, Cambridgeshire, UK), and green kale (Brassica oleracea L. var. CN Kal 1028, CN Seeds, Cambridgeshire, UK). Seeds were sown in coconut coir plugs and germinated for 3 days in dark conditions (22.0 °C; 95–98% RH), then moved to a propagation area (100 µmol m⁻² s⁻¹; 18 h d⁻¹). At 8 DAS, plants were transferred to the growing area for 22 days. Plant density was 525 plants m⁻² for green kale, 437 plants m⁻² for pak choi, and 146 plants m⁻² for crispy and canasta lettuce. Plants were cultivated in a hydroponic ebb-and-flow system (EC = 1.9 mS cm⁻¹; pH = 5.5) under stable environmental conditions (23 °C day / 21 °C night; 68% RH; 850 ppm CO₂). The experimental design was a randomized block design; the experiment was repeated three times with two replicates per cycle per treatment and species, yielding 6 replicates per treatment per species (n=6). Each replicate represents the mean of 10 measured plants. --- ## Light Treatments | Treatment | Photoperiod | PPFD (µmol m⁻² s⁻¹) | DLI (mol m⁻² d⁻¹) | Light Integral (mol m⁻²) | |----------------------------------------|--------------|----------------------|-------------------|--------------------------| | **14/190 (Short photoperiod)** | 14 h d⁻¹ | 190 | 9.75 ± 0.15 | 205 ± 3 | | **18/150 (Intermediate photoperiod)** | 18 h d⁻¹ | 150 | 9.75 ± 0.15 | 205 ± 3 | | **24/115 (Continuous light)** | 24 h d⁻¹ | 115 | 9.75 ± 0.15 | 205 ± 3 | All treatments used the same full white spectrum LED fixtures (Valoya Ltd, Helsinki, Finland): 13% blue (400–500 nm), 20% green (500–600 nm), 61% red (600–700 nm), and 6% far-red (700–750 nm). --- ## Measurements Collected - **Morphological**: plant height with a ruler, leaf number, leaf length and leaf width of fully developed leaves (cotyledons excluded) - **Biomass**: fresh and dry weight of leaves; dry weight obtained after drying at 60 °C for 3 days - **Yield**: expressed as kg m⁻² based on plant density per species - **Leaf area**: measured using the Easy Leaf Area app (University of California, USA) - **Derived indices**: Dry Matter Content (DMC, %), Specific Leaf Area (SLA, cm² g⁻¹ DW), Light Use Efficiency (LUE, g DW mol⁻¹), Lighting Energy Use Efficiency (L-EUE, g FW kWh⁻¹) --- ## Instruments & Methods - **Environmental control**: 23 °C day / 21 °C night; RH 68%; CO₂ 850 ppm - **Leaf area measurement**: Easy Leaf Area app, University of California, USA - **Precision balance**: dry weight determination after oven drying at 60 °C for 3 days - **Statistical analysis**: one-way ANOVA with Tukey post-hoc test (p ≤ 0.05), performed in RStudio version 4.4.1 (Posit Software, PBC, USA); normality and homogeneity of variances verified using Shapiro–Wilk and Levene tests --- ## Dataset Structure The dataset is organized in a single sheet in `Database_NaraDLI.csv`, with data for all four species (CanastaLettuce, CrispyLettuce, PakChoi, GreenKale), each with 18 observations (6 replicates × 3 treatments). All variables are fully described in the table below. --- # List of variables ### `Database_NaraDLI.csv` — all species, from line 1 to 73 | Variable | Description | Unit | |--------------------------------|-----------------------------------------------------------------------------|---------------| | `Species` | Crop species (CanastaLettuce, CrispyLettuce, PakChoi, GreenKale) | — | | `Treatment` | Light treatment (14/190, 18/150, 24/115) | — | | `Replicate` | Biological replicate (1–6) | — | | `PlantHeight` | Plant height at harvest | cm | | `LeafFreshWeight` | Fresh weight of leaves per plant | g | | `Yield` | Yield per unit area | g m⁻² | | `LeafNumber` | Number of leaves per plant | — | | `LeafLength` | Length of fully developed leaves | cm | | `LeafWidth` | Width of fully developed leaves | cm | | `LeafArea` | Leaf area per plant | cm² | | `LeafDryWeight` | Dry weight of leaves per plant | g | | `LightUseEfficiency` | Light use efficiency (dry weight / mol of light received) | g DW mol⁻¹ | | `LightingEnergyUseEfficiency` | Lighting energy use efficiency (fresh weight / energy consumed by LEDs) | g FW kWh⁻¹ | | `SpecificLeafArea` | Specific leaf area (leaf area / leaf dry weight) | cm² g⁻¹ DW | | `DryMatterContent` | Dry matter content (leaf dry mass / leaf fresh mass) | % | --- Notes The data are presented in the following publication: Prandi R., Carotti L., Pennisi G., Martin M., Gianquinto G., Orsini F. Inspecting the optimal photoperiod and light intensity combination for indoor cultivation of leafy vegetables in a commercial vertical farm.