Re-growing mint plants in Science

At the end of our topic last half term, we set up the following investigation: how long do asexual plants take to reproduce and what are the best conditions to reproduce them?

We decided to leave the cuttings of a mint plant in water in three different locations: on the roof (under cover so rain water couldn’t mix), in the cupboard and on the classroom window sill. We had learned in previous lessons that asexual plants can reproduce themselves but we wanted to know in what conditions and how long they will take. We ensured the test was fair by keeping the following variables the same: the amount of water they were in, the size of the cuttings, the measuring jugs and the amount of time they were left for. The one variable we changed was the location. Today, after a month, we took a look at the cuttings to see what had happened.

Our observations

1. The leaves of the cutting left in the cupboard had mostly fallen off and had turned brown. The water had discoloured as well. The plant appeared not to be very well, however five large roots had grown from the stem and there was clear evidence of reproduction
2. The cutting left on the window sill had the most developed roots, the leaves had not fallen and remained green.
3. The water level of the cutting on the window sill had decreased by 170ml, while the water level for the cutting on the roof decreased by 80ml and the water level for the cutting left in the cupboard decreased by 100ml.
4. The cutting left on the roof did show evidence of reproduction but the root growing from the cutting was very small, many of the leaves remained green and had not fallen.

Our next job is to answer the question ‘how long will it take to reproduce an asexual plant?’ So, we’re going to plant the cutting from the window sill in soil, water it regularly, leave it in its location and see what happens…

What conclusions do you think we drew from our observations?