Hydroponics
Technical & Teaching Notes
Introduction and Context
This practical activity outlines how to grow plants hydroponically in the classroom. It aims to give students an
understanding of the basic growth needs of plants. It also shows how hydroponics can be utilised to provide food to
humans as our population expands.
This new protocol was written by science technician Helen Bailey, based on the techniques she has developed for
her school, and funded by a SAPS Associates Award (www.saps.org.uk/awards). If you have any feedback or
further suggestions on the protocol, please let us know at [email protected].
Safety Notes
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See CLEAPSS recipe card 66 for Sach’s culture solution (complete recipe), Chemicals are LOW HAZARD.
Follow good hygiene practices after handling chemicals.
Beware, Plant Gro lighting system may get hot.
Apparatus
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Plant Gro propagation lighting system
Air stones & air line
Aquarium bubblers
Netting
Tubs- 4 to 5 litre, opaque or covered in black plastic
Nutrient solutions: Sach’s culture solution (complete recipe)
Seeds (e.g. Indian mustard, Wheat)
24 hour plug timer
Optional - Data logger with 2 temperature probes, light intensity meter, pH meter
Suppliers
Blades Biological (www.blades-bio) supplies appropriate seeds, air stones and air lines
Data Harvest supply data loggers.
Background Information
Hydroponics means growing plants in a nutrient solution, without soil. Hydroponics allows a gardener to grow
plants in a more efficient and productive manner. The concept of soil-less gardening has been around for
thousands of years. Scientists started experimenting with soil-less gardening around 1950.
Benefits of hydroponics Plant growth rates are 30 to 50% faster than a soil plant grown under the same
conditions.
Science & Plants for Schools: www.saps.org.uk
Hydroponics: p. 1
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
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Extra oxygen stimulates root growth
Extra oxygen also aids absorption of nutrients by the roots
The plant does not need to use up energy searching for nutrients
Soil-borne pests and diseases are minimized
All of the necessary growth elements are readily available. Lighting, temperature etc. can be automated
Hydroponics can also be of benefit to prevent soil erosion. Areas of desert can be transformed into areas of
productive land.
Instructions
1) Germinate the seeds-The instructions for germination vary depending on the seeds selected. Instructions for
Mustard and Wheat are outlined below. Please see reference number i) for further information.
Wheat
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Soak the seeds overnight
Roll the seeds up in wet tissue paper, place the seeds a few cm’s from the top of one edge of the paper
Put the roll into a plastic bag and tie the top, leaving room at the top of the bag for the seedlings to grow
into
Put the bag into a container so that it is held upright
After 3-4 days transfer the seedlings to the hydroponic set up
Mustard
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Place seeds on moist filter paper on a large Petri dish.
Place the Petri dish in the dark
Once the seeds have germinated, approx 3-4 days later, transfer them to the hydroponic set up
2) Set up the hydroponics system- Obtain a food storage tub and cut out a section of the lid. Replace the cut
out section with netting ensuring that the netting is loose enough that the seedlings will touch the nutrient
solution. Ensure that the tub is either opaque or cover it in black polythene so that the roots will be in the dark.
3) Make up the nutrient solution following CLEAPSS recipe card number 66 - Plant mineral requirement solutions.
4) Set up the plant-gro lighting system, plug into the mains through a 24-hour timer so that the light/dark ratio can
be set. When doing this, bear in mind the ambient temperature of the room the apparatus is being set up in.
5) Set up the aquarium bubbler, attaching the airline and airstone. Set up as shown in the diagram on the student
sheet.
6) Ensure that the nutrient solution level is kept topped up and changed entirely at least weekly.
7) Fill in the data sheet (below), making observations on plant growth and the growth parameters.
Science & Plants for Schools: www.saps.org.uk
Hydroponics: p. 2
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
Picture 1: Showing Wheat & Indian Mustard grown together using
Sach’s complete recipe & missing nitrogen
Picture 2: Showing the apparatus set up
Further Investigations
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Effect of nutrients on plant growth - Using Sach’s mineral deficiency recipes
Effect of lighting schedule on plant growth
Effect of temperature on plant growth
Acid rain investigations
Phytoremediation - See separate investigation sheet
References
i)
ii)
iii)
Biology Experiments, Teaching & Learning Resources by DG Mackean
http://www.biology-resources.com/biology-experiments2.html#Germination
CLEAPSS recipe card number 66 - Plant mineral requirement solutions
Hydroponics in the classroom, (Mar 1997) Merran Sell, School Science Review, v78 n284 p73-78
Science & Plants for Schools: www.saps.org.uk
Hydroponics: p. 3
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.
Sample Data
Nutrient solution used
Sach’s culture solution complete recipe
or follow mineral deficient recipes
depending on the outcome being studied
Date of last nutrient
solution change:
}Needs to be changed at
least weekly or when level low
Seeds
Plant (strain/variety)
Date sown
Germination date
Transfer date
Lights
On time 16 hours on
Off time 8 hours off
}Use a plug timer to set light
on and off times
Room Temperature
}Could be monitored with a
Day
data logger or normal
thermometer
Night
Observations/Comments
Root length
Shoot length
Science & Plants for Schools: www.saps.org.uk
Hydroponics: p. 4
This document may be photocopied for educational use in any institution taking part in the SAPS programme.
It may not be photocopied for any other purpose. Revised 2012.