Crop Guide: Nutritional recommendations for Cucumber - Haifa-Group

allowed to develop on the lower 75 cm (30 inches) of the main stem to encourage the plant’s rapid
vegetative development. Main-stem fruits above that point are allowed to develop at the base of
each leaf.
More than one fruit may begin to develop at each node. Some growers thin these to a single
vigorous fruit, but it may be more practical to leave all young fruits attached, because it has been
observed that more than one may mature
Fruit thinning
Overbearing can sometimes be a problem. To prevent the plants becoming exhausted and to
improve fruit size, control the number of the fruit per plant through selective fruit thinning. This
technique is powerful, so use it with great caution. The optimum number of fruits per plant varies
with the cultivar and, even more, with the growing conditions. Although, limiting the number of
fruits per plant invariably results in premium-priced large fruit, growers risk underestimating the
crop's potential or failing to forecast good weather. They may decide to remove too many fruits
and thus unnecessarily limit production. Fruit thinning is undoubtedly most useful in the hands of
experienced growers who can use it to maximize their financial returns. Fruit to be pruned must be
removed as soon as it can be handled, before it grows too large.
Irrigation
Maximum yields and fruit quality will be realized only if the plants receive adequate and timely
moisture. Cucumber plants have shallow roots and require ample soil moisture at all stages of
growth. When fruit begins setting and maturing, adequate moisture becomes especially critical.
The objective of watering is to maintain a fully adequate supply of water to the plant roots without
soaking the soil to the extent that air cannot get to the roots. Do not wait until the plants start to
wilt. A good practice is to dig into the soil and judge how much water remains before starting the
next irrigation. Regular watering on the same day of the week is unwise. The needs of the plants
change daily and seasonally. Water young plants planted in the greenhouse in January or February
only once every 5-10 days and then only enough to wet 15-20 cm of the soil. Similar plants growing
in June may need 5-10 fold as much water. Let the soil texture and structure determine how much
water to add at each application. By examining the soil before watering and several hours
thereafter, you can assess the effectiveness of the water application. Depending upon soil type and
growth conditions, approximately 25–50 mm of water per week is needed to obtain high quality
cucumbers. An irregular water supply, particularly during blossoming and fruit development, can
detrimentally affect fruit quality and result in increased nubins or hooked fruit.
The pH of the water is also critical and may need to be adjusted. The target pH of the nutrient
solution supplied to the plants should be between 5.5 and 6.0. Nitric, sulfuric, or phosphoric acid
are recommended for reducing the pH if it is above 7. If the source water is alkaline due to high
bicarbonate concentrations, the pH should be adjusted before the fertilizer salts are added to
prevent precipitation. If it is necessary to raise the pH, potassium hydroxide is usually used.
Important: Irrigation timing should not interfere with pollination and should allow surfaces to dry
before nightfall.
The drip irrigation system is better than most other conventional soil irrigation systems, because it
can be used to control crop growth by regulating the supply of water and nutrients. The drip
system also allows reduced relative humidity (RH) in the greenhouse, because not all the soil is
irrigated and because the system is compatible with the use of white polyethylene film as a lightreflecting
mulch. In countries suffering from lack of good irrigation water the drip irrigation
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