452 
Soilless culture under greenhouse conditions 
attracts scientific interest and increased in por-
tions of the world where it has not been common 
practice. The occurrence of soil-limited factors 
(expensive chemical soil disinfection methods, 
low yields and possible plant residues, water 
shortage and increase in salinity of natural soils) 
has increased demand for a suitable technology 
adapted to soilless culture (De Rijck and Schrevens 
1998) and exploitation of local materials for use 
as growing media with specific physicochemical 
properties (Ortega et al. 1996). Inorganic substrates 
such as perlite, sand and pumice, are chemically 
inert, making it possible to supply nutrients in a 
controlled manner (De Rijck and Schrevens 1998). 
Several studies reported the favorable effect that 
organic materials have on plant growth (Sawan 
and Eissa 1996, Tehranifar et al. 2007, Tzortzakis 
and Economakis 2008), as increased substrate po-
rosity and water holding capacity (Hardgrave and 
Harriman 1995). Arancon et al. (2004) reported 
that organic matter (vermicompost) applications 
increased strawberry growth and yields signifi-
cantly, including increases of up to 37% in leaf 
areas, 37% in plant shoot biomass, 40% in numbers 
of flowers, 36% in numbers of plant runners and 
35% in marketable fruit weights.
Sawdust is widely used as a growth medium com-
ponent in areas with wood processing industries, 
because of its low cost, high moisture retention, 
and high availability. Sawdust has been standard 
growing medium for the greenhouse industry in 
Alberta and Argentina for several decades (Sawan 
and Eissa 1996). Usually it forms a constituent (nor -
Use of sawdust, coco soil and pumice in hydroponically 
grown strawberry
E. Marinou1, A. Chrysargyris2, N. Tzortzakis1,3
1Department of Organic Greenhouse Crops and Floriculture, Technological Educational 
Institute of Crete, Heraklion, Greece
2Department of Biology, University of Crete, Heraklion, Greece
3Department of Agricultural Sciences, Biotechnology and Food Science, 
Cyprus University of Technology, Limassol, Cyprus
ABSTRACT
Strawberry (Fragaria × ananassa Duch.) plants were grown hydroponically in different ratio of sawdust (Saw-100), 
coco soil (Coc-100) and/or pumice (Pum-100) mixtures. Leaf number doubled in plants grown in Saw-100 while 
runners (stolons) number increased up to 70% in plants grown in Coc-100 compared with the control treatment 
(Pum-100). Fruit number increased (up to 50%) in plants grown in Pum-100. Leaf stomatal conductance, photo-
synthetic rate and internal concentration of CO2 differentiated according to the plant vegetative or reproductive 
stage and/or substrate medium. Leaf and stem fresh weight as well as leaf area was increased (up to 32, 24 and 44%, 
respectively) in case of Coc-100 compared with the Saw-100 or Pum-100. Plant yield was doubled when Pum-Saw 
(50-50) was used compared with the Saw-100, which is due to the reduced fruit number produced rather than the 
difference in fruit fresh weight. Substrate affected fruit quality parameters. The present findings highlight the puta-
tive use of organic medium i.e. Sawdust on top of the widely used coco soil as substrate medium in strawberry cul-
ture.
Keywords: organic materials; plant growth; soilless culture; yield; marketability
Vol. 59, 2013, No. 10: 452–459 Plant Soil Environ.
 453
mally less than 50%) in mixtures rather than being 
used as a stand-alone growth medium. However, 
sawdust is prone to gradual decomposition which 
leads to unfavourable substrate physical properties 
converting it from ‘dry’ to ‘wet’ substrate with a 
higher volume of retained water and a deficiency 
of available oxygen. The air-to-water ratio in the 
root zone originating from differences in physical 
properties of the growing media is of great impor-
tance (Gizas and Savvas 2007). Despite perlite’s 
(as inorganic substrate) higher stability, there was 
no improvement in productivity found for bell 
pepper or long English cucumber when compared 
to sawdust (Nichols and Savidov 2009). Indeed, 
coir was the better substrate when compared to 
sawdust for the long English cucumber crop, but 
sawdust was preferable substrate for the bell pep-
per crop (Savidov 2005).
The objective of the present study was to compare 
the performance of sawdust, coco soil and pumice, 
alone and in mixtures for strawberry (Fragaria × 
ananassa Duch.) cultivation.
MATERIAL AND METHODS
Experimental design. Strawberry (Fragaria × 
ananassa Duch. cv. San Andreas), plants were 
grown under natural light during spring in an 
unheated plastic greenhouse in Crete, Greece. 
Average minimum and maximum air temperatures 
during this period were 16°C and 32°C, respectively. 
Three substrates, pumice (Pum; as control treat-
ment), sawdust (Saw), coco soil (Coc) and mix-
tures of these, were used to create six treatments 
which were: (1) Pumice (Pum-100); (2) Sawdust 
(Saw-100); (3) Coco soil (Coc-100); (4) Pum-Saw 
(50-50); (5) Coc-Saw (50-50); (6) Coc-Pum (50-50). 
Plants were obtained from California (US Davis), 
defrosted slowly in room temperature and directly 
transplanted in the substrates. Each substrate was 
filled (5 L) in multi-channels (POLYGAL Plastic 
Industries Ltd, Ramat Hashofet, Israel). The six 
substrate mixtures with four replications (multi-
channel)/treatments (with 11 plants/replication) 
were arranged in single rows on a greenhouse 
trough. Rows were 1.0 m apart and plants were 
separated in multi-channel by 0.2 m. Drip irrigation 
emitters (four emitters/multi-channel) were placed 
at the top of each multi-channel which had slits in 
the bottom to allow drainage. Pumice and coco soil 
were obtained by local supplier and sawdust derived 
from Sweden pine (Pinus sylvestris L.) trees was 
obtained by a local furniture manufacture, while 
the wood was not treated with any chemicals. The 
soilless culture system was open with the excess 
nutrient solution drained away. A solution (1:100 
v/v) in water containing the following concentration 
of nutrients: NO3
–-N = 14.29, K = 10.23, ΡΟ4-P = 
0.97, Ca = 3.74, Mg = 2.88, SO4
2–-S = 1.56 and Na = 
1.30 mmol/L, respectively; and Β = 18.52, Fe = 
71.56, Μn = 18.21, Cu = 4.72, Zn = 1.53, and Μο = 
0.52 μmol/L, respectively. Fertigation was applied 
during the daytime through a timer (1 min every 1 h 
at a flow rate of 25 mL/min) with a drip irrigation 
system (via emitters) by means of pressure pumps. 
Nutrient solution target pH and electrical conduc-
tivity (EC) were 5.9 and 2.1 mS/cm, respectively.
Substrate properties. The physicochemical 
properties of pumice, coco soil and sawdust mix-
tures were examined in three replicants. Organic 
matter content was determined (ashed at 550°C/8 h) 
and the organic C was calculated. The EC and 
pH determined according to 1:2 dilution method. 
After a hydrochloric digestion of the sample ash, 
nutrients analysis for K and Na (photometric; 
JENWAY, PEP-7 Jenway, Dunmow, UK), P (spectro-
photometric; Pye Unicam Hitachi U-1100, Tokyo, 
Japan) was determined while total N determined 
through Kjeldahl method. The main physical prop-
erties of the used substrates, determined according 
to De Boodt and Verdonck (1972). Particle size 
distribution values were determined by dry siev-
ing with a mesh sizes of 8, 4, 2, 1, 0.5, 0.25 and 
0.075 mm (Electromagnetic & Digital Sieve Shaker, 
ΤΖΒΑ200Ν, BWB Technologies Ltd, Berks, UK).
Plant growth and development. Beginning 
second week after transplanting, the impact of 
substrate medium on plant growth/development, 
yield and nutrient uptake in strawberry was studied. 
Biweekly, the following parameters were measured: 
the number of runners (stolons), leaf number, fruit 
number, fruit fresh weight, yield, fruit size, mar-
ketability (score 1–4; 1 – extra quality; 2 – good 
quality; 3 – medium quality; 4 – non market-
able); total soluble solids (TSS); titratable acidity 
(TA); total phenolics (as described previously in 
Tzortzakis et al. 2007). Leaf chlorophyll (chl a and 
chl b) content was determined according to Porra 
(2002) while leaf fluoresces, photosynthetic rate 
(Pn), stomatal conductance (gs) and internal leaf 
concentration of CO2 (Ci) were determined using 
a portable infra-red gas analyser (model Li-6200; 
Li-Cor, Inc., Lincoln, USA). Measurements were 
Plant Soil Environ. Vol. 59, 2013, No. 10: 452–459
454 
carried out between 9:00–11:10 AM, the leaf tem-
perature within the chamber was 28 ± 2°C, photo-
synthetic photon flux density of 1300 μmol/m2/s 
was used at the ambient CO2 concentration. The 
Li 6200 was equipped with a leaf chamber with 
constant area inserts (6.0 cm2). All gas-exchange 
measurements started 3 h after the onset of the 
photoperiod and were replicated in nine plants in 
each treatment and on two fully expanded, healthy, 
sun-exposed leaves per plant.
In experiment completion, fresh weight and dry 
matter content (%) of stems and leaves and leaf area 
produced were measured. Leaf elemental analysis 
for K, Na (photometric), P (spectrophotometric; 
vanadomolybdophosphoric yellow colour method) 
and N (Kjeldahl) were determined in the end of 
the experiment. 
Statistical analysis. Data were tested for nor-
mality, and then subjected to analysis of variance 
(ANOVA). Significant differences between mean 
values were determined using the Duncan’s multiple 
range test (P < 0.05) following one-way ANOVA. 
Statistical analyses were performed using the SPSS 
(SPSS Inc., Chicago, USA).
RESULTS AND DISCUSSION
Substrate properties. The amount of pore space 
of media is critical physical characteristic which 
influences water and nutrient absorption and gas 
exchange by the root system (Sahin et al. 2002). 
For sufficient gas exchange, drainage, and water-
holding capacity, the proper proportion of ma-
cropores is necessary. Several studies indicated that 
particle size and hydraulic properties of pumice 
affected growth and yield of greenhouse crops 
(gypsophila, rose, cucumber, lettuce) in soilless 
culture (Gizas and Savvas 2007). In the present 
study, organic matter (and as a consequence the 
organic carbon content) was increased in Saw-100 
compared with Coc-100 (Table 1). The most sub-
strates particle size was under 2 mm. Adding pum-
ice into the sawdust substrate altered the negative 
properties of aeration and balance water content 
of the latter. In previous studies, physical analysis 
of substrates confirmed that particle size distribu-
tion was determined by the proportion of sawdust 
and sand. Dry and wet particle density increased 
while organic matter content and total porosity 
decreased with the addition of sand (Sodre et al. 
2007). An increased EC (averaged 3.08 mS/cm) 
was observed in Coc-100 and affected substrate 
EC was reported in different mixtures. Saw-100 
affected medium acidity (revealed – 4.71 pH) 
and contributed to the increased amount of N, K 
and P (Table 1), while no changes were revealed 
for Na content. Additionally, Coc-100 added nu-
trient amount of K and P, but also Na. Organic 
media improved total porosity when used alone 
or mixed with Pum-100. Oxygen deficiency may 
readily occur in media with relatively low air-filled 
porosity, especially if plants exhibit high growth 
rates, which demand intensive root respiration (as 
Table 1. Physicochemical properties of different mixtures consisted of pumice, coco soil and sawdust
Organic matter Organic C
pH EC (dS/m)
N K P Na
(%) (mg/g)
Pum-100 – – 7.87 0.45 0.01 ~0.000 0.024 ~0.000
Saw-100 92.6 54.8 4.71 0.74 10.80 0.032 0.055 0.006
Coc-100 89.2 52.6 5.46 3.08 0.01 0.119 0.219 0.175
Coc-Saw 50-50 91.2 53.1 5.37 1.59 9.06 0.136 0.082 0.042
Pum-Saw 50-50 47.5 23.7 6.13 0.53 5.49 0.011 0.034 0.005
Coc-Pum 50-50 43.4 22.3 6.65 1.41 0.10 0.082 0.054 0.041
particle size 
distribution
bulk density 
(g/cm3)
water content air capacity total porosity
(%)
Pum-100 < 8 mm 0.631 23.2 38.6 67.5
Saw-100 < 4 mm 0.117 33.0 13.2 89.8
Coc-100 < 8 mm 0.121 71.8 23.3 95.1
Coc-Saw 50-50 < 8 mm 0.168 47.8 18.0 91.3
Pum-Saw 50-50 < 8 mm 0.326 52.3 27.4 71.6
Coc-Pum 50-50 < 8 mm 0.349 42.6 29.1 73.9
Vol. 59, 2013, No. 10: 452–459 Plant Soil Environ.
 455
reviewed by Gizas and Savvas 2007). Cultivation 
of bell peppers (cv. Sardana) performed better 
on perlite, a ‘dry’ substrate, than on coir which 
seems to have a higher demand for oxygen supply 
in the root zone, when grown at two levels of CO2 
(Savidov 2005).
Plant growth/yield. The number of leaves dif-
fered among plants growing in different substrates 
after the 6th week of plant culture (Figure 1). Leaf 
number increased up to 50% in plants grown in 
Saw-100 and up to 34% in plants grown in substrate 
mixtures compared with the control treatment 
(Pum-100), while no differences were observed 
among substrate mixtures. Similarly, leaf number 
was greater in strawberry plants grown in media 
containing peat rather than inorganic substrates, 
such as perlite or sand (Tehranifar et al. 2007). 
The number of stolons increased up to 70% in 
plants grown in Coc-100 compared with the re-
spective plant grown in Saw-100 or Pum-100, 
yet no differences were observed in plants grown 
in substrate mixtures (in 50:50 ratio) (Figure 2), 
which is in agreement with previous findings in 
strawberry plant when grown in seven media. 
However, plants produced most runners in Coc-100 
and the least in perlite (similar inorganic media as 
pumice) (Tehranifar et al. 2007). Guttrige (1985) 
also reported that number of runners of strawberry 
plants is different in different cultivars and under 
different growth conditions.
Fruit number increased (up to 50%) in plants 
grown in Pum-100 in comparison with plants 
grown in Coc-100 and all substrate mixtures, while 
no differences were observed among Pum-100 
and Saw-100 (Figure 2). Fruit number produced 
in plants grown in Coc-100 did not differ with 
the equivalent number produced in Saw-100, and 
this is in agreement with previous studies when 
three tomato cultivars were grown in Saw-100 
and Coc-100 (Sawan and Eissa 1996). Similarly, 
strawberry plants grown in sand 100% produced 
flowers earlier than in other growing media, in-
cluding organic/inorganic mixtures with Cocopeat 
(Tehranifar et al. 2007).
Leaf and stem fresh weight increased (up to 
32% and 24%, respectively) in case of Coc-100 
compared with the Saw-100 or Pum-100 (Table 2). 
Additionally leaf area was markedly increased 
Figure 1. Effect of different sub-
strate medium on the leaf number 
produced in hydroponically grown 
strawberry. Values are means ± SE 
according to the Duncan’s multiple 
range test
Figure 2. Effect of different substrate medium on the stolon (early stage) and fruit (late stage) production in 
hydroponically grown strawberry. Values are means ± SE according to the Duncan’s multiple range test
St
ol
on
 n
um
be
r
2                           4                           6                           8
Weeks
5
4
3
2
1
0
8                               10                              12
Stolon production Fruit production
Fr
ui
t n
um
be
r
3
2
1
Coc-100
Saw-100
Pum-100
Coc-Saw 50-50
Coc-Pum 50-50
Pum-Saw 50-50
2                     4                    6                     8                   10                   12
Weeks
18
16
14
12
10
8
6
4
2
0
Coc-100
Saw-100
Pum-100
Coc-Saw 50-50
Coc-Pum 50-50
Pum-Saw 50-50
Le
af
 n
um
be
r
Plant Soil Environ. Vol. 59, 2013, No. 10: 452–459
456 
(up to 44%) in case of Coc-100, i.e. 1641.1 cm2, 
compared with the Saw-100 or Pum-100 (885.4 
and 828.2 cm2, respectively), while plants grown 
in substrate mixtures revealed intermediate values. 
Plant dry matter content did not differ among 
plants grown in different substrates.
The greatest fruit number harvested per plant 
was marked in plants grown in Pum-Saw (50-50) 
compared with others substrates (Table 2). When 
three strawberry cultivars grown in seven sub-
strates – including peat, coco soil, perlite, sand and 
their mixtures of the higher plant yield fluctuated 
for the same substrates media and was cultivar 
dependent. Thus cv. Camarosa in cocopeat-perlite 
(40-60), cv. Gaviota in 100% peat and cv. Selva in 
100% cocopeat produced higher yields (Tehranifar 
et al. 2007).
Plant yield increased in Pum-Saw (50-50) com-
pared to Pum-100, Coc-Pum (50-50) and Saw-100. 
In more details, plant yield was doubled with Pum-
Saw (50-50) used, compared with the Saw-100, 
which is rather due to the reduced fruit number 
produced than due to the difference in fruit fresh 
weight (Table 2). Similarly to the present study, 
tomato plant yield did not differ in plants grown in 
Coc-100 and in Saw-100 (Sawan and Eissa 1996). 
When sawdust, rockwool, coir and perlite were 
used for the production of bell pepper, long English 
cucumber and tomato, they showed a similar level 
of productivity in most applied conditions (Nichols 
and Savidov 2009), which contradicts the present 
outcomes regarding the impact of organic and in-
organic medium on plant productivity but is in ac-
cordance with lettuce production in sawdust and/or 
perlite (Christoulaki et al. 2013). These may be 
due to different plant species and/or experimental 
treatments. Indeed, composted sawdust consists an 
alternative medium, and may substitute inorganic 
substrates with beneficial effects (Dorais et al. 
2006). Yields in peat-bark substrates were similar 
to rockwool substrates during greenhouse tomato 
culture grown in plastic bags but were lower in 
sawdust (Allaire et al. 2005) being in agreement 
to some extent with the present study. Similarly, 
coir had no negative effect on the production of 
long English cucumbers during all three years of 
the experiments. Yield of the coir increased by up 
to 12.4% compared to sawdust. Thus, compared to 
sawdust, coir, with a flatter water retention curve, 
appears to be the most appropriate substrate for 
long English cucumber (Savidov 2005).
Leaf gas exchange. During stolon production 
(vegetative stage), the greatest leaf stomatal con-
ductance was observed in plants grown in Coc-Pum 
(50-50), followed by Pum-Saw (50-50) while the 
least leaf stomatal conductance was observed in 
plants grown in Pum-100 (Figure 3). However, dur-
ing the fruit production (reproductive) stage, Pum-
100 and Coc-Saw (50-50) revealed significantly 
higher leaf stomatal conductance. Plants grown in 
substrate mixtures (Coc-Saw 50-50; Coc-Pum 50-
50; Pum-Saw 50-50) revealed higher photosynthetic 
rate during vegetative stage compared with raw 
substrates (Figure 3), possible due to the better 
physiological status of plant development and/
or improved media physicochemical properties. 
Moreover, plants grown in Coc-100 and substrate 
mixtures (Coc-Saw 50-50; Coc-Pum 50-50; Pum-
Saw 50-50) had higher internal concentration of 
CO2 in both vegetative and reproductive stage 
compared with Saw-100 and Pum-100 (Figure 3). 
Greater Sawdust content (75% or 100%) in sub-
Table 2. Effect of different substrate medium on the stem and leaf fresh weight (FW) and dry matter content 
(DM), leaf area, yield, fruit number and fruit fresh weight produced in hydroponically grown strawberry. In 
each column, mean values followed by the same letter do not differ significantly at P = 0.05 according to the 
Duncan’s multiple range test
Stem FW 
(g)
Stem DM 
(%)
Leaf FW 
(g)
Leaf DM 
(%)
Leaf area 
(cm2) 
Yield
(g/plant)
Fruit 
number
Fruit FW 
(g)
Pum-100 20.7c 20.6a 25.9c 29.3a 828.2c 32.9b 2.6b 14.6a
Saw-100 25.7bc 19.7a 31.8b 27.6a 885.4c 26.9b 2.6b 11.3b
Coc-100 37.8a 18.8a 42.5a 29.4a 1641.1a 34.8ab 2.8b 12.6ab
Coc-Saw 50-50 29.6b 17.7a 36.4ab 26.6a 1120.3bc 40.4ab 2.6b 15.6a
Pum-Saw 50-50 22.1bc 18.6a 29.4bc 26.9a 887.5bc 49.4a 4.2a 11.3b
Coc-Pum 50-50 36.3ab 16.6a 37.7ab 30.1a 1185.6b 29.3b 2.8b 10.6b
Vol. 59, 2013, No. 10: 452–459 Plant Soil Environ.
 457
strates reduced lettuce leaf photosynthetic rates as 
well as stomatal conductance in previous studies 
(Christoulaki et al. 2013). No differences were 
observed in leaf fluoresce and chlorophyll con-
tent among the different substrates (data not pre-
sented) being in accordance with previous studies 
in lettuce (Christoulaki et al. 2013). During plant 
growth, no symptoms of nutrient deficiency or 
toxicity observed optically. However, in previous 
experiments regarding seedling growth in differ-
ent substrates, including sawdust, the Fv/Fm ratio 
was not a good indicator of the plant phytotoxicity 
(Dorais et al. 2006).
Fruit quality parameters. Examined fruit qual-
ity parameters as presented in Table 3; no differ-
ences were observed in fruit length while fruits 
derived by plants grown in Coc-Saw (50-50) and 
Pum-100 were wider than the equivalent fruits by 
Saw-100, Pum-Saw (50-50) and Coc-Pum (50-50). 
Fruit marketability revealed lower values in plants 
grown in Coc-Saw (50-50) and this might be due 
to substrate physicochemical properties alteration 
by mixing two organic substrates (i.e. sawdust 
and coco soil).
Mean fruit fresh weight increased in plants grown 
in Coc-Saw (50-50) and Pum-100 compared with 
Figure 3. Effect of different substrate medium on leaf photosynthetic rate; stomatal conductance and intercel-
lular CO2 concentration of fully expanded leaves in hydroponically grown strawberry. Values are means ± SE 
according to the Duncan’s multiple range test
Ph
ot
os
yn
th
et
ic 
ra
te
 
(μ
m
ol
/m
2 /
s)
18
16
14
12
10
Weeks
2                   4                   6                   8                   10                 12
2                   4                   6                   8                   10                 12
St
om
at
al 
co
nd
uc
ta
nc
e 
(m
m
ol
/m
2 /
s)
In
te
rn
al 
co
nc
en
tra
tio
n 
of
 C
O
2 
(μ
m
ol
/m
ol
)
0.6
0.5
0.4
0.3
0.2
320
300
280
260
240
2                   4                   6                   8                   10                 12
Coc-100
Saw-100
Pum-100
Coc-Saw 50-50
Coc-Pum 50-50
Pum-Saw 50-50
Plant Soil Environ. Vol. 59, 2013, No. 10: 452–459
458 
fruits harvested in plants grown in Saw-100, Pum-
Saw (50-50) and Coc-Pum (50-50) (Table 2). Fruits 
obtained by Saw-100 substrate were more acid 
compared with fruits obtained by Pum-Saw (50-50) 
and Coc-Pum (50-50) as presented in Table 3. No 
differences observed in TSS among treatments, be-
ing in agreement with previous study in strawberry 
plant grown in cocopeat 100%, cocopeat-perlite 
(40-60), perlite 100% and sand 100% (Tehranifar 
et al. 2007). In previous studies, coco soil affected 
positively tomato fruit quality i.e. TSS while per-
lite mixtures with carbonized rice hull improved 
plant yield (Inden and Torres 2004). The content 
of total phenolics increased in fruits obtained by 
Coc-100 compared with fruits obtained by Pum-
100, Coc-Saw (50-50) and Saw-Pum (50-50).
Nutrient concentrations in plant tissues. 
Examining nutrient status in leaves, there were no 
differences among basic nutrients such as K content 
(averaged 2.12 mg/g FW), Na content (averaged 
0.089 mg/g FW), P content (averaged 0.53 mg/g 
FW) and N content (averaged 17.47 mg/g FW). 
Similarly, no main differences were observed on 
K, N and P lettuce leaf content when sawdust was 
added into perlite substrates (Christoulaki et al. 
2013) as well as in tomato plants grown in rockwool 
or hinoki [Chamaecyparis obtusa (Sieb. et Zucc.) 
Endl.] bark fiber slabs (Yu and Komada 1999).
The increase in the production of potted plants 
and/or substrate culture, and thus the increase 
in demand for substrates, has focused worldwide 
horticultural research on the search for local ma-
terials which are readily available and affordable, 
with physical and chemical characteristics which 
make them likely to be suitable for use as growing 
medium. In most cases, these requirements have 
led to a concentration on by-products, the most 
important of which (by volume) are plant waste 
products, particularly from the forestry industry 
(sawdust, barks) and the food industry (grape and ol-
ive marc) (Ortega et al. 1996). Although agricultural 
re-use of plant wastes is well established, especially 
in the case of fertilizers, their use as substrates can 
involve problems of toxicity. These problems can 
have serious consequences owing to the direct con-
tact with the plant in concentrated form. Methods 
such as composting, ageing, washing, mixtures or 
fertilization have been used to reduce or eliminate 
the negative impacts. Indeed, the determination of 
sawdust medium content that may be mixed with 
inorganic substrates is quite valuable.
In conclusion, the present findings highlight 
the putative use of organic medium i.e. Sawdust 
on top of the widely used coco soil as substrate 
medium in strawberry culture. The performance 
of plants grown on Pum-Saw (50-50), followed by 
the Coc-Saw (50-50) and then by Coc-Pum (50-50) 
is markedly influenced by the media and the al-
teration of physicochemical properties (such as 
porosity, water content and air capacity) of raw 
material and hence the air and water balance in 
the root environment. Further research study is 
necessary for the complete exploitation of the 
putative use of sawdust in substrate mixtures as 
pure or composted material and of its ability to 
improve physicochemical properties as substrate 
medium, indentifying the exact ratio mixed into 
substrates as well as appropriate container height 
(to improve hydraulic properties of the media), 
for hydroponically grown crops.
Table 3. Effect of different substrate medium on the fruit size, fruit marketability (1 – extra quality; 2 – good 
quality; 3 – medium quality; 4 – non marketable); total soluble solids (TSS); titratable acidity (TA) and total 
phenolics in hydroponically grown strawberry. In each column, mean values followed by the same letter do not 
differ significantly at P = 0.05 according to the Duncan’s multiple range test
Fruit length Fruit width Marketability 
(score 1–4)
TSS 
(Brixo)
TA 
(% citric acid)
Total phenolics 
(μmol GAE/g FW)(cm)
Pum-100 3.2a 3.0a 3.03ab 5.90a 7.75ab 3.91b
Saw-100 3.1a 2.6b 3.11ab 6.35a 8.06a 4.08ab
Coc-100 3.2a 2.9ab 3.21a 6.18a 7.53abc 4.88a
Coc-Saw 50-50 3.4a 3.1a 2.77b 6.56a 7.11abc 3.70b
Pum-Saw 50-50 3.1a 2.7b 3.35a 5.96a 6.56c 3.62b
Coc-Pum 50-50 3.2a 2.6b 3.37a 6.08a 6.88bc 4.17ab
Vol. 59, 2013, No. 10: 452–459 Plant Soil Environ.
 459
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Received on April 27, 2013
Accepted on September 11, 2013
Corresponding author:
Dr. Nikos Tzortzakis, Cyprus University of Technology, Faculty of Geotechnical Sciences and Environmental 
Management, Department of Agricultural Science, Biotechnology and Food Science, 3603, Limassol, Cyprus
e-mail: nikolaos.tzortzakis@cut.ac.cy
Plant Soil Environ. Vol. 59, 2013, No. 10: 452–459