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THECOMMERCIAL GREENHOUSEGROWER • APRIL 2018
HORTICONTACT TOUR •
WilkoWisse stressedproducing tomatoes is all about
keepingon topof costs. “Labour accounts for a thirdof
our costs at this 9.5ha site, energy another third and all
other costs the remaining third.”
The company’s five locations useCropHeat Processors
togenerate electricity, hot water andCO2, andwhen
all five are added together thebusiness generates a
staggering35mWof electricity! The threeCHPs at the
sitewe visitedgenerating a total of 9.3Mw (3.1Mw each),
whichwe are informed is sufficient topower 40,000
homes!
The nursery grows six different types of cocktail tomatoes
on substrates, some of theplants providedbyAxia
VegetableSeeds. Theplantswe saw arrived as 60cmhigh
ones inAugust, and the first trusseswere harvested six
weeks later. One truss is picked everyweek until week 50,
bywhich time theplant has reached a lengthof 12-13m.
During thewinter, they harvest from 2.5 stems/m² and in
the summer 4-4.5 stems for the same sq.m. During the
winter, staff levels are around3.5/ha, which increases to
5.5/haduring the summer, and the grower averages a
productionof around 50kg/m²/yr.
Crop is harvested in twodifferent ways. The first is
directly intoboxes for customerswhere they are sold as
twobrands –RedPearl andHarvest of Health. Second,
trusses are graded at the sorting station for delivery to the
auction.
At the endof August, they have 10-14days to remove
the crop and substrates, and clean the house toprepare
it for the next one.White fly is one of the fewpestswhere
chemicals are used, but biological control is used to
control 90%of pests.
MrWisse explained that 1m³ of natural gas is converted
into 40% electricity and 60% hot water. The latter is
stored in a 4,500m³ tank. Pumped into the house at 90
degreesC, it is returned at 70degreesC and reheated.
CO2 is alsoproduced.
Given the fact that grow lights result in a typical increase
inproductionof around 25% in all types of tomatoes, then
it will come as no surprise to learn that their popularity
continues to increasewithDutchgrowers at the rate of
10-15% a year. It is estimated that around 38%of the
total Dutch tomato area is nowgrownunder lights.
The 1000w fittings suspended aboveVander Lans’
tomatoes generate 13,000 lux. The lamps in the 9.5ha
greenhouse consume 11,000kw/hr, roughly equivalent
to thedemand for three homes for a year. They produce
9,000kw/hr on site, andbuy in the other 2,000.
Screens ensure 98%of it remains in the glasshouse,
which fromOctober toApril are generally switchedon at
lunchtime andoff at 6am, and a total of 3,500 to 4,000
hours a year. They donot use the lights fromApril to
September. Looking ahead, theHPS lamps at one of the
grower’s locations needed replacing, and last September
were swapped for a 3ha LED trial.
WorldHorti Center
Next on the agendawas a stop at thebrand-new €22
million-costing initiative called theWorldHorti Center
(WHC). Privately fundedby themajor partners of theMBO
Westland school, theGreenport Food&Flower Xperience
Foundation, DemokwekerijWestland and the local
Westlandgovernment, theNaaldwijk location iswithin
easywalkingdistance of theRoyal FloraHolland auction.
Thebuildingwork started inSeptember 2016, and you
have to tip your hat to theDutch for the newpremises,
which are expected to attract aminimumof 25,000
international visitors a year. Ameltingpot of innovation
and research, in addition to 42glasshouse research
departments (6,400m²), the exhibition areaprovides an
opportunity for some 80 companies tohighlight all the
latest in technical innovations.
StefanPersoonof Inno-Agroprovideduswith some information
of a fewof theprojects underway in theWHC’s 42glasshouse
research compartments.
Previewed at GreenTech2016, Priva’sKompano tomatode-
leafing robot is on show at theWorldHorti Center.
