1. Pre-kick off Meeting, 1 February 2021
INFLUENCING FACTORS IN OBTAINING
MICROGREENS IN HYDROPONIC
CONDITIONS
The 20th International Conference Life Sciences for Sustainable Development,
23-25 September, 2021, USAMV Cluj-Napoca
Teodor RUSU, Paula Ioana MORARU* and Mihai Avram MAXIM
University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Romania
*Corresponding author, e-mail: paulaioana.moraru@usamvcluj.ro

2. Pre-kick off Meeting, 1 February 2021 2
 ERANET, ICT-AGRI-FOOD, European and International Cooperation,
 Subprogram 3.2_Horizon 2020, Contract no. 201/2020
 Project title: A smart-sensing, AI-driven platform for scalable, low-cost hydroponic units
P1 - SCiO Private Company, https://scio.systems, Grecia
P2 - University of Copenhagen, https://www.ku.dk/english, Danemarca
P3 - Holisun SRL, https://www.holisun.com, Romania
P4 - Nr21 Design, https://www.nr21.com, Germania
P5 - Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research
“Demokritos”, https://inn.demokritos.gr, Grecia
P6 - University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca (USAMV Cluj-Napoca)
https://www.usamvcluj.ro
○ The 20th International Conference Life Sciences for Sustainable Development,
○ 23-25 September, 2021, USAMV Cluj-Napoca

3. Pre-kick off Meeting, 1 February 2021 3
Asmart-sensing,AI-drivenplatformforscalable,low-costhydroponicunits
3
https://www.gohydro.org
Main project activities
 Review and analysis of the factors that affect microgreens growth and nutrient quality;
 Appropriate selection of sensing devices to be included in the GOhydro platform as a multi-modal sensor kit;
 Development of an artificial intelligence (AI) component implementing a multi-model approach that will be able to
produce accurate predictions and recommendations with limited amounts of data;
 Evaluation cycles (in Greece, Denmark and Romania) of incremental proximity to the realistic usage of the platform,
i.e., as a stand-alone hydroponic unit installable in everyday settings (offices, houses) and requiring no expertise to
be managed and configured.
○ The 20th International Conference Life Sciences for Sustainable Development,
○ 23-25 September, 2021, USAMV Cluj-Napoca

4. Pre-kick off Meeting, 1 February 2021
Timeline
USAMV Cluj-Napoca two-year action plan:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
4
T 5.2 - Communication and
dissemination
T 4.1 - Task protocol
preparing
T 4.2 - Production trials in
hydroponic units
T 4.3 – Performances
validation
T 1.1 - Literature review

5. Pre-kick off Meeting, 1 February 2021
Expected results
5
Scientific publications:
- Journal publications
- Conference proceedings
Deliverables
D4.1 Trial protocols for microgreens production in hydroponic units (R, PU)
[M15]
A report detailing the methods, materials and hydroponic units to be used for the
GOHYDRO trials both in controlled and operational settings.
D4.2 Evaluation results from experiments in semi-controlled realistic
installations (R, PU) [M21]
A report presenting and analysing the results and insights gained from the pilots
under controlled settings
D4.3 Report on validation of microgreens production in operational settings
(R, PU) [M24]
A report presenting and analysing the results and insights gained from the pilots
under operational settings

6. Documentation related to hydroponic crops:
• Introduction
• Importance of microgreens
• Cultivation of microgreens in hydroponic system
• The nutrient solution (pH, electrical conductivity, temperature and dissolved oxygen in water)
• Metabolism of microgreens and biotic and abiotic stressors
• Disease and pest control in hydroponic crops
- 164 bibliographical references
Project proposal for literature review:
 nutrient requirements and production parameters
 lighting needs for hydroponically grown microgreens: effect of light parameters on crop growth, nutrient profile and
yield; light quality, light intensity and photoperiod effects on microgreen growth and development
 different production parameters like: pH, electrical conductivity, humidity, dissolved oxygen, temperature (of air
and water) and nutrients

7. Aims: In this paper is presented a review of the literature, which demonstrates that the
production of microgreens using hydroponic systems must be organized with care for
controlling the many environmental and production parameters to achieve desired outputs
and of an adequate quality.
Materials and Methods: The review of the literature and data collection followed in detail
certain keywords relevant for the production of microgreens in hydroponic systems, such as:
species, temperature, humidity, pH, electrical conductivity, oxygen dissolved in water, carbon
dioxide, nutrient solutions, and the influence of light (quantity, quality and photoperiods).
INFLUENCING FACTORS IN OBTAINING MICROGREENS IN
HYDROPONIC CONDITIONS
The research was conducted between December 2020 and August 2021, using the databases: Web of Sciences,
Scopus, Science Direct, Google Scholars.

8. No. Systems Characteristics Website
1 Wick System
The plants are placed in a container, on an absorbent growth medium, and
the connection to the tank with nutrient solution is made with absorbant
wicks, through which the nutrient solution circulates to the level of the
plant roots
www.hydroponics.eu
2 Drip System
The plants are installed on a medium, the nutrient solution is transported
from the solution tank through drip tubes; the excess solution reaches the
tank again and recirculates again through the system.
www.trees.com
3 Ebb and Flow System
It works according to the principle of flooding the growing environment in
which the roots of plants with nutrient solution are located. A pump
pushes the nutrient solution out of the tank, and then the excess drains
back slowly, allowing the plants to receive nutrients regularly.
www.nosoilsolutions.com
4 Deep Water Culture
(DWC) System
The plants have their roots immersed directly in the nutrient solution and
float above it. As support, you can use expanded polystyrene plates with
perforations in which the plants are inserted. Oxygenation of the solution
is necessary.
www.epicgardening.com
5 Nutrient Film
Technology (NFT)
This system ensures a constant flow of nutrient solution directly to the
plant roots. The plants grow in perforated polyethylene tubes and PVC
pipes. The pumping system is essential in this system.
www.thespruce.com
6 Aeroponic System
Involves suspending the plants on top of sprayers that directly spray the
roots with nutrient solution every few minutes. The advantages of this
system are the use of a much smaller amount of water, the roots receive
oxygen in large quantities and the plants grow faster. However, the roots of
the plants being suspended in the air, they are more prone to drying faster
than in any other hydroponic system.
https://aeroponicsdiy.com
7 Aquaponic Systems
It integrates aquaculture and hydroponics into a single culture system. The
water used in these crops comes from the fish farming system. They
secrete nitrogen compounds that are captured and used by plants in their
growth, prolonging water use and reducing the adjustment of the nutrient
solution for plants.
www.futurefarming.group
Overview of hydroponic systems

9. No. Lactuca sativa L. Reference Light colour Effect on growth
1 Lettuce - Green Salad Bowl
Legendre and van
Iersel, 2021
Far-red 700–800 nm
Increasing supplemental far-red light increased leaf length and width, which was associated
with increased projected canopy size
2
Green leaf lettuce (Lobjoits green cos) and
red leaf lettuce
Viršilė et al., 2020 Green 510 nm
Green light had reasonable impact on the contents of nutritive primary metabolites in red
and green leaf lettuce
3
Lettuce - var foliosum cv. Dubacek and cv.
Michalina
Sergejeva et al., 2018 Blue 440 nm
Compact plant morphology; impact of illumination source on the dry matter content
significantly depended on cultivar and sampling time
4 Lettuce - Frillice Crisp Pinho et al., 2017 Far red 700–850 nm
Addition of far red light increased leaf area index; faster growth may have caused decrease in
dry weight content
5
Lettuce - Sunmang seedlings from 16 days-
old
Lee et al., 2016 Far red 700–850 nm
Improved shoot and root growth; with far-red LEDs improves lettuce growth and bioactive
compound content in a closed-type plant production system
6 Red lettuce - Sunmang Lee et al., 2015 Far red 700–850 nm
The number of leaves increased, leaves were longer; the results of this study suggest that the
supplementation with far-red LEDs should be considered when designing artificial lighting
systems for closed-type plant factories
7
Lettuce - cultivars, red leaf Sunmang and
green leaf Grand Rapid TBR, 18 day
seedlings for 4 weeks
Son and Oh, 2015 Green 490–550 nm
The substitution of blue with green LEDs in the presence of a fixed proportion of red
enhanced growth of lettuce
8 Red leaf lettuce - cv. Banchu Ref Fire Johkan et al., 2012 Green 490–550 nm
High intensity (300 μmol m−2 s−1) green LED light promoted lettuce growth; 510 nm light had
the greatest effect on plant growth
9
Red leaf lettuce seedlings - cv. Banchu Red
Fire
Johkan et al., 2010 Blue 425–490 nm
Resulted in compact lettuce seedling morphology; promoted the growth of lettuce after
transplanting
10 Baby leaf lettuce - Red Cross Li and Kubota, 2009 Far red 700–850 nm
The fresh weight, dry weight, stem length, leaf length and leaf width significantly increased by
28%, 15%, 14%, 44% and 15%, respectively, with supplemental FR light compare to white
light
11 Red leaf lettuce - Outeredgeous Stutte et al., 2009 Far red 700–850 nm
Leaf elongation; total dry weight of plants grown under red LEDs alone was ≈20% lower than
plants with blue or far red added
12 Red leaf lettuce - cv. Outeredgeous Stutte et al., 2009 Blue 425–490 nm Leaf expansion; the addition of blue light allowed full development of anthocyanin to occur
The effect of light colour on growth of lettuce

10. No. Reference Investigation context Treatment Results (can be yield, quality and quantity, chlorophyl, etc.)
1 Bulgari et al., 2021 Influence of three growing media (vermiculite, coconut fiber, and jute
fabric) on yield and quality parameters of two basil varieties (green and
red)
Microgreens were grown in a floating Micro Experimental
Growing system equipped with LED lamps, with modulation
of both energy and spectra of the light supplied to plants
Results showed high yield, comprised from 2 to 3 kg m−2; nutritional quality varied among species and higher antioxidant
compounds were found in red basil on vermiculite and jute; coconut fiber allowed the differentiation of crop performance in terms
of sucrose and above all nitrate; the choice of the substrate significantly affected the yield, the dry matter percentage and the
nitrate concentration of microgreens
2 Manawasinghe et
al., 2021
Influence of substrate: nutrient film technique (NFT) culture, in
comparison with conventional soil, culture and compost mixed coco-
peat substrate
The treatments were: top soil (control; T1), as compost
and coir dust mixture at the rate of 1:1 (T2) and NFT (T3);
the pH and EC of the supply solution were 5.9 (at
27.9°C) and 1.5 mS cm-1, respectively
A significantly high vegetative growth and total yield was found in the NFT grown basil; the nitrate accumulation in basil leaves was
well below the maximum permissible limit (MPL), set-forth by the recommendations of the European Health Commission
3 Pannico et al.,
2020
Identification and quantification of polyphenols, major carotenoids and
macro micro-minerals; twenty-seven phenolic compounds were
quantified, of which the most abundant were: cichoric acid and
rosmarinic acid in basil
Sodium selenate applications at three concentrations (0, 8,
and 16 μM Se) on green and purple basil; Hoagland nutrient
solution; pH: 6; EC: 0.35 dS cm−1
In green and purple basil microgreens, the 8 μM Se application enhanced the lutein concentration by 7% and 19%, respectively; the
same application rate also increased the overall macroelement content by 35% and total polyphenols concentration by 32% but
only in the green cultivar; the latter actually had a tripled chicoric acid content compared to the untreated control
4 Puccinelli et al.,
2019
Selenium biofortified microgreens from selenium-enriched seeds of
basil; subtrate: perlite and vermiculite; pH: 5.6; EC: 2.04 dS m−1
Basil plants were grown in a nutrient solution, containing 0
(control), 4 or 8 mg Se L−1 as sodium selenate
Seeds from plants treated with Se showed a significantly higher germination index than seeds from control plants; and the
microgreens were enriched in Se; the antioxidant capacity of Se-fortified microgreens was higher compared to the control
5 Scagel et al., 2019 Effect of salinity on biomass yield; for every 10 mM increase in NaCl,
treatment solution EC increased 1.1 dS m-1; pH: 5.1-5.2; hydroponic
solution pH decreased slightly during the experiment (7.5 to 6.8) but all
treatments had similar pH
Two basil cultivars were grown hydroponically for 71 d with
four different concentrations of NaCl (no NaCl, low,
moderate, and high (20 dS m-1)
In both cultivars, salinity increased leaf concentrations of certain caffeic acid derivatives, caftaric acid, cinnamyl malic acid, and
feruloyl tartaric acid and decreased concentrations of chicoric acid; salinity increased leaf concentrations of the two of the major
polyphenolics in basil leaves, quercetin-rutinoside and rosmarinic acid; salinity decreased concentrations of rosmarinic acid in
leaves
6 Bulgari et al., 2017 Yield, mineral uptake, and quality of basil, Swiss chard, and rocket
microgreens
Hoagland’s nutrient solution; pH: 5.56; EC: 1.12 dS cm−1;
minimum and maximum temperatures: 9.7-43.1°C;
microgreens were harvested at the first true leaf stage, with
green and swollen cotyledons
With reference to data reported in literature for the same species hydroponically grown but harvested at adult stage, these
microgreens yielded about half, with lower dry matter percentage, but higher shoot/root ratio; they showed high concentrations of
some minerals, but their nutrient uptake was limited due to low yield; nitrates content was lower if compared with that usually
measured in baby leaf or adult vegetables of the same species, as well as the concentration of chlorophylls, carotenoids, phenols,
and sugars
7 Saha et al., 2016 Nutritional dynamics Compared between aquaponic and hydroponic systems
using crayfish (Procambarus spp.) as the aquatic species
Aquaponic basil (AqB) showed 14%, 56%, and 65% more height, fresh weight, and dry weight, respectively, compared to hydroponic
basil (HyB)
8 Walters and
Currey, 2015
Quantify productivity and characterize growth of 35 basil cultivars
grown in two hydroponic production systems
In this two, two hydroponic systems were compared -
nutrient film technique (NFT) and deep flow technique (DFT)
systems, grown for 3 weeks
Fresh weight of plants grown in DFT systems was 2.6 g greater compared with plants grown in NFT systems. Basil cultivars differed
greatly in fresh weight; however, the yield of basil seems to be affected more by cultivar selection than hydroponic production
system
9 Kiferle et al., 2013 The nutrient solutions contained different NO3
- concentrations (0.5, 5.0
and 10.0 mol m-3) or NO3
-/ NH4
+ molar ratios (1:0, 1:1 and 0:1; total N
concentration was 10.0 mol m-3); concentration of other nutrients were
as follows: 1.0 mol m-3 P-H2PO4, 10.0 mol m-3 K+; 3.0 mol m-3 Ca2+; 1.5
mol m-3 Mg2+ plus trace elements
Influence of nitrogen nutrition on growth and accumulation
of rosmarinic acid in sweet basil
The use of a total NO3
- concentration of 5 mol m-3 resulted in optimal plant growth and rosmarinic acid production; this suggests
that the standard N concentration used in hydroponic culture (10 mol m-3 or higher) could be reduced considerably, with important
implications from the environmental point of view; in contrast, the addition of NH4
+ to the nutrient solution was detrimental to both
growth and rosmarinic acid production
Studies on effects of Nutrient solution, pH, EC, and Substrate on basil grwoth and production

11. No. Parameter Unit of measurement Average value of parameters
1 Light W 400
1.1 Photoperiodicity h 07:00–20:00 (12h)
1.2 Light intensity μmolm−2s−1 400
1.3 Color spectrum nm 440-460
1.4 Position cm 150 – Lamps HPS (High Pressure Sodium)
40 - Lamps LED
2 Ambiental temperature °C 20 ± 2
3 Humidity % 80 ± 5
4 Nutrient N-P-K : 3-2-3 (5-1-5) changed every 10 days
5 pH pH units 6.3 ± 0.4
6 Electrical conductivity mS 1.8 ± 0.2
7 Dissolved oxygen mgL−1 6
8 Solution temperature °C 18 ± 2
Needs of lettuce microgreens grown in a hydroponic system

12. No. Parameter Unit of measurement Average value of parameters
(parameter variation)
1 Light W 400
1.1 Photoperiodicity h 06:30-21:30 (15h) (10-20h)
1.2 Light intensity μmolm-2s-1 300 (200-400)
1.3 Color spectrum nm 440-460 (260-780)
1.4 Position cm 150 – Lamps HPS (High Pressure Sodium)
40 - Lamps LED
2 Ambient temperature °C 21±2 Day; 17 Night
3 Humidity % 65±5 (50-60)
4 Nutrient N-P-K : 3-2-3 (%) changed every 10 days
5 pH pH units 6.8±0.4
6 Electrical conductivity mS 1.2±0.2
7 Dissolved oxygen mg L-1 6.5
8 Solution temperature °C 20±2
Environmental needs of basil microgreens grown in a hydroponic system

13. The literature review undertaken here has demonstrated that the production of basil microgreens using
hydroponic systems must be organized with care for controlling the many environmental and production
parameters to achieve desired outputs that are of an adequate quality.
This paper has shown that the nutritional solution, temperature and light regime have the most important
role in seed germination and development, while also summarizing the recent research on the many
promising explorations in refining microgreen production to achieve optimal outputs along its phenological
stages.
Results and Conclusions

14. The nutritional solution, temperature and light regime, pH,
electrical conductivity, dissolved oxygen and temperature are
all important factors which influence secondary metabolism
from an incipient phase, which in the final stages increases
both the perceived and actual value of the plants by
contributing to human health and nutritional fortification.
This literature review has shown that microgreen producers
must integrate specific systematic hydroponic strategies to
obtain high quality microgreens and high quantity and
quality bioactive substances, while also avoiding the potential
for spoilage and low-quality production when moving too far
beyond the noted parameter ranges summarized here.
It is necessary to standardize certain cultivation protocols to
ensure their quality. This high degree of control necessary for
optimal growth is also a benefit of hydroponic systems, as the
sophisticated organization can lead to the elaboration of certain
protocols to control as many factors which can positively, and
negatively, influence plants in order to obtain a crop as uniform
as possible throughout the year, with higher concentrations of
active substances and nutrients valuable for human health.

15. 1. Rusu, T., 2021. GoHydro – O nouă perspectivă în producția microplantelor (GoHydro - A new perspective in the production of
microgreens). Agricultura 365, Anul IX, nr. 45, mai-august 2021, pag. 46-47. ISSN 2343-9580, ISSN-L 2343-9580, Tipografia
Inkorporate Print București.
2. Rusu, T., P.I. Moraru, O.S. Mintas, 2021. Influence of environmental and nutritional factors on the development of lettuce (Lactuca
sativa l.) microgreens grown in a hydroponic system: A review. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 49(3), Article
number: 12427 (FI: 1.444). DOI: 10.15835/nbha49312427.
3. Rusu, T., R.J. Cowden, P.I. Moraru, M.A. Maxim, B.B. Ghaley, 2021. Overview of multiple applications of basil (Ocimum basilicum
L.) and the effects of production environmental parameters on yields and secondary metabolites in the hydroponic system.
Sustainability, 13, x. https://doi.org/10.3390/xxxxx. (FI: 3.521). https://www.mdpi.com/journal/sustainability
Publications

16. ThankYou
Teodor RUSU, Paula MORARU, Mihai MAXIM
+40 724 719 774
trusu@usamvcluj.ro;
moraru_paulaioana@yahoo.com
http://www.usamvcluj.ro/
A smart-sensing AI-driven platform for scalable,
low-cost hydroponic units
FUNDED
BY
https://www.gohydro.org/