Recommendation on growing greenhouse Beit-alpha cucumbers
Based on recommendations prepared by:
Eng. Nabeel Gnayem- Extension specialist, Ministry of Agriculture- Israel
Necessary Climates, Soil, and Structures.
Greenhouse cucumbers adapt to variable climates, and can achieve economically feasible yields in both hot
and cool weather (Between 8 and 37 Centigrade). Extreme conditions beyond outside of this range, can
cause stress, lower yields, and lower fruit quality. Heating or cooling to readjust the greenhouse climate
can improve yield and quality in extreme conditions.
Day Length - Parthenocarpic cucumbers are not sensitive to day length.
Humidity- Cucumber plants develop well in relatively high humidity(65-85%). They suffer in extremely
dry weather. In desert conditions, adding humidity should be considered.
Light- Cucumbers develop well in high light conditions (250 to 1000 watts/sq meter). In higher light
intensity, there is a need for shading. Lack of light (below 100) severely decreases plant development.
Soil types- Adaptable to many types of soil types providing they have fairly deep profiles, and pH between
6.5 and 7.5. Calcitic and alkaline soils obligate constant attention to microelement levels.
Structures- High structures are preferred (above 4 m), and spacious structures facilitate optimum humidity
levels. Tropical and subtropical climates require a ventilated roof. In places where climate drops below 5
centigrade, heating is necessary. It is necessary to choose structures that enable trellising up to 2.5 meters
high. Anti insect nets should be used in order to decrease virus infection, and physical insect damage
caused by aphids and white flies. Plastic should be chosen according to local growing conditions, and it is
usually recommended to use thermal plastic (IR and anti drip).
Planting recommendations- Plant density should be selected based on season, and plant characteristics of
the particular variety. Average plant density in spring/summer conditions is between 2.4 and 2.6 plants/m2.
When planting in double rows, row spacing should be 50 –60 cm , and bed spacing should be 1.8 meters
center to center, and plant spacing within the row should be 35-40cm. During winter/autumn conditions,
plant density is decreased to 1.8 to 2.2 plants/ m2. This density can be achieved by planting 40cm between
plants in double rows.
Fertilizer- Levels should be adapted to age of plant, soil type and climate. Fertilizer levels should be given
according to soil and irrigation water testing. Furthermore, general fertilizer recommendations need to be
checked to see that they are adaptable to local conditions.
Irrigation- Evapotranspiration measurements are the most reliable sources to guide proper watering
practices. A general rule of thumb is that irrigation should be given at a level equivalent to 30-40%
evapotranspiration from planting to 14 days, flowering to first harvest 40-60%, and until the end of the
harvest 60-90%,
Fertilizer- Intensive planting of greenhouse crops requires pre-plant fertilization based on soil analysis,
followed by continuous supplemental fertilization. General fertilizer recommendations in Israel can be
found in the following table.
Crop Age
0 – 14 days
Flowering to harvest
After first harvest
Gram per 1000m2 per day
Elemental N
Phosphorus
Potash
100
40
80
150-200
40
200-300
250-300
40
350-400
Crop Age
0 – 14 days
Flowering to harvest
After first harvest
N
60-80
100-120
120-140
Gram per cubic meter water
P
K
Ca
25-35
50-70
60-80
25-30 140-160
80-100
30-40 160-180
80-100
Mg
35-40
35-40
35-40
Pruning and trellising- After planting trellising strings must be prepared for each plant. String length
needs to be from the cable to the ground plus an additional 15cm. A week after planting the strings are
wrapped around the plants. Strings should be wrapped again every 7 days in the summer, and every 10
days in the winter. Up to the first two internodes, all side shoots should be removed. From the third
internode until 50 cm, side shoots are left on, but apex is pruned after 2 internodes in the spring and
summer, and 1 internode in the winter. After 50cm, apex of the side shoots should be pruned on a regular
basis after 2-3 internodes. After harvest begins, leaves are pruned up to 50 cm height on the plant. If
leaves are showing symptoms of diseases, these leaves should be removed also.
General Plant Protection recommendations. – During the growth stage, all diseased plants or parts of
plants should be removed to maintain sanitation within the greenhouse. At the end of growth, plants need
to be removed in their entirety and discard them outside of the greenhouse. Resistant varieties should be
used when possible. Greenhouse should be well ventilated to prevent diseases. Foot baths should be used
at the entrance of the greenhouses with 1% bleach to prevent spread of viruses that spread mechanically.
Hands should be disinfected by using soap during harvest and other chores. Pesticide should be used
according to manufacturer recommendations including harvest intervals, and only those registered for use
on cucumbers. Aphids and white flies can be controlled by use of Conifdor/Actara according to
recommendations. Every 5 days, plants should be inspected for diseases and insects. One day after
spraying, affectivity should be evaluated. Formulation of spray materials (pesticide doses, spay volumes,
etc.) should be adjusted to obtain maximum affectivity, while using the minimum amount of pesticide
necessary.
Harvest, and Post-Harvest Handling
Harvest begins from 23 to 45 days after planting according to weather conditions, and variety. Harvest last
between 50 and 120 days. Harvest is done by hand by removing fruit with stem attached. Flowers should
be removed at harvest time to improve shelf life, and reduce breakdown of the fruit. Harvesting should be
done early in the morning while the fruit is firm and cool, and not hot and soft. Cartons should not be
stacked too high, to prevent crushing of fruit on the lower levels of the stack.
Grading of fruit- Defective fruit, insects, etc should be removed before packing. Size grading can be done
by machine in the packing house, and washed by water at 55 to 58 centigrade for 20 seconds, and then
dried by cool air to improve appearance and shelf life.
Packing- packing should be done according to needs of wholesalers. It is common to place a foam pad on
the bottom of each box to maintain freshness and reduce shrinkage. Cucumbers can be held in coolers at
10-12 centigrade and relative humidity of 90-95% for up to 10 days.