made by hemang singhal

1. Greenhouse
MADE BY HEMANG SINGHAL FROM 7A,
SCIENCE HOLIDAY HW

2. What is a
Greenhouse?
• A greenhouse is a structure with
walls and roof made chiefly of
transparent material, such as glass, in
which plants requiring regulated
climatic conditions are grown.
• These structures range in size from
small sheds to industrial-sized
buildings.
• The interior of a greenhouse
exposed to sunlight becomes
significantly warmer than the external
temperature, protecting its contents
in cold weather.

3. How do they grow
plants?
• Warmth and humidity promote
plant growth. Plants need moisture,
warmth and light to grow. A
greenhouse stabilises the growing
environment by buffering the ambient
temperature and protecting the plants
from extreme cold. This extends the
growing season at both ends, so in late
winter and early spring it enhances the
growing conditions for plants and
allows them to start into growth
earlier than they would when growing
outdoors.

4. How light is regulated?
• Greenhouses are constructed with
long-sides facing south-east to south-
west to maximize sunlight.
• The objects in a greenhouse are
painted so they reflect as much light as
possible.
• The covers used in a greenhouse are
either made of glass or plastic which are
transparent, which enables light to
easily enter inside.

5. How water is
regulated?
• Many greenhouses use capillary mats
for watering the plants. These mats are
placed under plant pots. They ooze water
slowly, which the drip holes of the
containers take up to the plant roots. This
reduces evaporation and prevents
overwatering. The excess water is
collected by plastic liners or a flood floor
that directs the water back into the system
to reuse for watering greenhouse plants in
other drip lines. Another method of
watering plants is the simple drip system,
which can be used to direct larger or
smaller flows of water directly to the
pots.

6. How carbon dioxide is
regulated?
• Controlling indoor air movement provides the
greenhouse plants with a constant supply of
carbon dioxide. Strategically placed horizontal
fans throughout a greenhouse allow air to press
closer to the foliage for peak photosynthesis
action. The concentrated carbon dioxide results
in larger leaves, stronger plant stems and
possible early flowering and fruiting. However,
air movement must be coupled with proper
ventilation. Closing off the greenhouse to
outside air circulation lowers indoor carbon
dioxide levels because the plants use the gas
quickly while transferring oxygen to the air in
exchange.

7. ADVANTAGES OF
GREENHOUSE
• A wider variety of plants can be
grown
• Diminish threats to crops
• Plants don’t depend on weather
condition in a greenhouse.
• No ploughing.
• Shorter harvest time
• Less staff.
• High profits.
• Clean crops.

8. DISADVANTAGES OF
GREENHOUSE
• Lots of planning needed.
• Alarms needed.
• Expensive to monitor.
• Electricity & gas needed to
maintain it.
• Expensive structure
• Lack of pollination
• Risk of theft
• Pest control at time

9. WHICH CROPS CAN BE
CULTIVATED?
• Tomatoes
• Basil
• Cucumber
• Spinach
• Peppers
• Herbs
• Green beans
• Raspberries
• Strawberries
• Grapes
• Cherries
• lemon

10. IMAGES