Hydroponics is the growth of plants without soil using a nutrient solution. The majority of tomatoes, cucumbers and sweet peppers are grown using hydroponics in large polytunnels and greenhouses. Hydroponics allows plants to grow in areas where soil quality is poor.
It is reasonable to ask the question ‘Will the concentration of nitrate in the nutrient solution affect the growth of plants?’
This question may be framed as a testable hypothesis: ‘The growth of cress seedlings will be increased with higher concentrations of nitrate in the hydroponics nutrient solution.’
Collect the following equipment: zz
Cress seeds
zz zz
zz Cotton wool and filter paper
Perlite (an inorganic medium for growing cuttings)
Approximately 4–7 days before you begin your investigation, you must sow cress seeds and allow them to germinate.
Task 2: Prepare your hydroponics planter
1 Using scissors, carefully cut the bottles in half so you can turn the top half upside down and rest it in the bottom half. Carefully drill a 10 mm hole in the bottle top. Cut a thin strip of cloth and pull it through the hole in the bottle top – this will act as a wick to absorb the hydroponic solution from the bottom of the bottle and then deliver it to the cress seedlings.
z 126 Cress z
zz zz zz zz zz
Glassware
Five 2 l plastic bottles Old tea cloth or towel Test tubes
