Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
• After germination the covering material is removed and the temperature is lowered to 23°C.
The young seedlings require
• good light conditions.
• proper aeration.
• optimum humidity
Transplanting
Plants are ready for transplanting in 6-8 weeks.
Plant Spacing
o Row x Row = 45cm,
o Plant x Plant = 30cm
7-8 plants/m2 should be planted.
Growth is dependent on temperature and humidity in greenhouse.
o transplants require a minimum day temperature of 21 - 23°C, and two degrees
higher during sunshine.
o night temperature of 20°C and
o high humidity (80%)
The root temperature must be sufficiently high (20-22°C). So for propagation under cold
conditions the use of benches or bottom heat is beneficial.
CO2 enrichment (to 700 ppm) promote growth of the seedlings from the stage where true
leaves are expanded.
High temperature during August adversely affects production but are good for young plant
growth.
Humidity
• During transplanting, humidity must be high, but overhead spraying is not advised as it
increases the risk of Botrytis.
• Air humidity is best around 80 % for plant growth.
Temperature
The optimal temperature after planting is 22/21°C (day/night) on the first days, and 23/22°C
(day/night) later.
The root zone temperature should be around 22°C.
o Lower increases the risk of Pythium.
o Too high causes too much growth and insufficient flower production.
High temperature reduces fruit set due to high rates of abortion in late spring and
summer, so ventilation and shade materials are required.
Cold weather affects yield due to poor pollination , earliness in production and delay
maturation, so bottom heating during night is recommended.
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