What it shows
Seeds lose the ability to sprout over time, and storage conditions change how fast. Testing old and new seeds kept in different ways shows how to store seed for the next season.
The science
Seeds slowly use up their food reserves and their cell membranes and enzymes age. Warm and humid storage speeds this up, so cool, dry storage keeps seeds alive longer. Old seeds sprout less and weaker seedlings result.
Materials
Cost: under Rs 50. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Seed lots of different ages (for example this year, last year and two years old)
- Petri dishes or plates with tissue
- Jars with lids, rice grains or ash
- Fridge space or a cool shelf
- A measuring cup and labels
- A notebook for counts
Safety
For this project: Wash hands after handling seeds. Do not use seeds treated with chemicals. An adult should handle jars stored in the fridge.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
Collect or buy seed lots of three different ages and write the age on each packet.
Take 20 seeds from each lot and place them on damp tissue in labelled dishes.
Keep them in the same warm spot and moisten daily.
Count germinated seeds each day for a week.
Also store fresh seed in three ways: an open dish, a sealed jar with rice and a sealed jar in the fridge for one week.
Test germination again after storage using ten seeds from each method.
Calculate germination percentage for each lot and method.
Present graphs for age and for storage method.
What you should see
Germination drops with seed age, and cool sealed storage keeps seeds better than open warm storage. Graphs show both effects.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1What is seed viability?
The ability of a seed to germinate.
2Why store seeds cool and dry?
It slows ageing and prevents mould.
3Why use the same number of seeds?
To compare percentages fairly.
4What do farmers do before sowing old seed?
Test germination and sow more thickly if it is low.
Take it further
Test whether soaking in water before sowing helps old seeds sprout.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
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