Comparison of Greenhouse Crop Yields in Growstone and Rockwool
Results from consecutive trials in the USA and The Netherlands, proved Growstones’ fruit yields
are as good as mineral wool (Figure 1 through 4). This is especially significant considering that
no CO2 enrichment was used.
35
30
kg m-2
25
20
15
10
Gowstones
Rockwool
5
0
0
2
4
6
8
10
12
14
16
18
Harvest Number
Figure 1. Tomato cumulative yields (kg m -2) in Growstones were within 4% of mineral
wool for a February - May 2007 crop season at The University of Arizona, Tucson, AZ.
N = 18.
50
2
Yield (kg per m )
40
100% Growstones
Growstones/Coco coir
Rockwool
30
20
10
0
1/1/08
2/1/08
3/1/08
4/1/08
5/1/08
6/1/08
7/1/08
Harvest
Figure 2. Tomato cumulative yield (kg m -2) for different Growstones based growing media
and mineral wool (Control) for Jan – June 2008 crop season at The University of Arizona,
Tucson, AZ. N = 10.
1
40
100% Growstones
Rockwool
Yield (kg per m2)
30
20
10
0
130
145
160
175
190
205
220
235
250
265
280
295
310
Date
m-2)
Figure 3. Tomato cumulative yields (kg
vs. harvest day in Growstones and mineral
wool for May 25 – October 17, 2007 crop season at Wageningen University and
Research Center, The Netherlands. N = 15.
Higher tomato yields observed in Growstones was due to significantly higher incidence of
blossom end rot (BER) in plants grown in mineral wool during a portion of the crop season,
compared with Growstones.
In cucumber greenhouse trials at Wageningen University Research, The Netherlands in
2006, Growstones yields slightly outperformed mineral wool, where there was a significantly
higher incidence of Pythium.
14
Yield (kg per m2)
12
Growstones
Rockwool
10
8
6
4
2
0
11/6/06
11/13/06
11/20/06
11/27/06
12/4/06
12/11/06
Date
Figure 4. Cucumber cumulative yields (kg m-2) in Growstones and mineral wool from
September to December 2006 crop season at Wageningen University Research (WUR), The
Netherlands.
2
In all these trials, Growstones yields were as high, and in some cases slightly higher than those
in mineral wool. Growstones also promoted reproductive plant growth with an earlier onset of
flowering and significantly lower incidence of BER.
These results were due to Growstones drier nature compared to mineral wool, making it easier
to control root moisture content at any given time and making it easier to bring a crop to a
balance between vegetative and reproductive growth. As such, Growstones has proven itself to
be the ultimate substrate in steerability.
Growstones high steerability is of practical significance particularly in climates or crop varieties
which tend to promote excessive vegetative growth with subsequent delays in production.
3