What is the Most Effective Way for Greenhouse Farmers to Have Success Growing Non-Seasonal Vegetables in Winter?
Most effective
Greenhouse
Non-seasonal Vegetables
Winter
Measures of effective growth
Biomass
Photosynthesis rates
Height of the plant
Ineffective as it only accounts for vertical growth and dismisses changes in the leaves, flowers etc.
Dry weight
Fresh weight
Measuring the weight immediately after removing the plant from the soil
Time-efficient
However, it accounts for the water retention of the plant, which is not synonymous to its growth, but rather its ability to absorb and store water
Drying the plant after removing it from the soil, then drying it in the oven before measuring its weight
Requires more time
Accounts for the growth better than the water retention of the plant
Oxygen increases
Carbon dioxide decreases
Moisture of the soil decreases
Could be measured through a tensiometer
Absorbing more moisture is not synonymous to leading to more growth
Could be measured using a CO2 probe
Does not need to account for cellular respiration of the plant
Could be measured using a O2 probe
Environmental conditions
Temperature
Humidity
Ventilation of air
Sufficient sunlight
Influences humidity (Department of Primary Industries, 2020)
Factors that lead to temperature fluctuation
Affected by the amount of sunlight
Affected by ventilation
What type of light?
Light intensity
Vegetables that grow in Summer
Conditions associated with Winter in which Winter vegetables grow best in
Low temperatures
Snow
High levels of rainfall
Low humidity
Shorter days
Low intensity of light
Mimic this in a lab condition through changing the moisture of the soill
Mimic this in lab conditions through incubators
Increase this in lab conditions through changing the number of hours the lamp is on for
Mimic this in lab conditions through changing the frequency of the light (i.e. its colour) in hertz.
Red light
Blue light
White light
Tomatoes
Zucchinis
Pumpkins
Would be difficult to grow in a lab given the time frame
Cabbage
Lettuce
Types of materials greenhouses are made from (Bagley, 2017)
Glass
Two types
Single pane
Double pane
Better light transmission
Aids in insulation, enabling the greenhouse to naturally be warmer
Good for plants which require high light intensity
Polyethylene
Enables oxygen and carbon dioxide diffusion due to its porous property
Fiberglass
Good light transmission
Good diffusion
Light scatters
Need to account for the oxygen that it is using up for cellular respiration
Vegetables which can be grown in labs
Spinach
Swiss chard
Photosynthetic floatation method can be applied
Arugula
Fast growing
Independent variable
Light intensity (lux)
Distance of the lamp from the plant
Frequency of light
Colour of light and their associated wavelengths in nanometers
Amount of water
pH
Use liming methods to manipulate the soil's pH
Adding NaOH to increase the pH
Adding HCl to lower the pH
Seasonal change of pH
pH decreases as temperature increases, as the denaturation of organic acids acidifies the soil (Onwuka & Mang, 2018)
pH decreases as rainfall increases (Onwuka & Mang, 2018)
Temperature
Nutrients given
Type of fertiliser
Results would be difficult to interpret as numerical values cannot be assigned to the "amount of nutrients" of each fertiliser
Can be measured through a temperature gauge or a greenhouse temperature monitoring system (AerIndustries, 2019)