- 6 seedlings of the same type of plant (make sure they’re similar in height and health) – they can be grown from seeds or bought from a nursery, or you can use living herb pots from the supermarket
- 6 empty pots or seedling punnets (unless your seedlings are already in their own separate pots)
- Potting mix (unless your seedlings are already in their own separate pots)
- Masking tape
- A pen or marker
- 6 plastic trays to put the pots on
- A spray bottle with water
- Access to a freezer, fan and heater or heat lamp
- Time and patience!
What to do
If your seedlings are not already in 6 separate pots, start at step 1.
If your seedlings are in separate pots, do step 1, then skip to step 6.
- Gather your materials on a flat surface, like a desk or kitchen table.
- Fill the empty pots with potting mix.
- Gently separate the seedlings and plant one in each pot.
- Put each pot on a tray and spray the pots well to soak the soil. Put the seedlings in the same location, somewhere with a bit of light, and let them settle for 1 week. Mist them with water every second day.
- After 1 week, make sure your seedings are still similar in height and health.
- Stick a piece of masking tape to each pot – these will be your labels.
- Label one pot ‘Control’ and leave it in the same location.
- Label one pot ‘Freeze’ and place it in the freezer overnight, then return it to the original location next to the ‘Control’ pot.
- Label one pot ‘Heat’ and place it in front of a heat source, such as a heating vent, heat lamp or very warm sun. Leave it here for the duration of the activity and mist it with water every second day.
- Label one pot ‘Wind’ and place it in front of a fan or ventilation system outlet that is regularly blowing air. Leave it here for the duration of the activity and mist it with water every second day.
- Label one pot ‘Wet’ and place it in the original location with the ‘Control’ pot. Mist it with water twice a day.
- Label one pot ‘Dry’ and place it in the original location with the ‘Control’ pot. Mist it with water every 4 days.
- Allow the plants to grow for at least 2 weeks, comparing them each time you mist them. Allow them to grow for longer if possible.
Questions to ask
Do you think different plants reacted differently in different climates? Try different types of seedlings and observe how they grow in each of the extreme situations.
Can you think of other extreme conditions that plants grow under (for example, in rocky or sandy ground, acidic soil)? How would you test how plants would grow in these conditions?
There is evidence that plants communicate with each other. How could you test if plants grow better closer to each other or further away? Do some plants mix better with others?
Plants can grow in some very extreme situations. In the Lake Taupo volcanic region in New Zealand, the dwarf swan-neck moss grows at temperatures around 72 °C in very acidic and metallic soils. Other mosses, and even a shrub, grow in soils just a few degrees cooler, at 68 °C. These plants adapt to the hot soils by having very short root systems because the soil becomes hotter the deeper they grow.