45 Minutes to Write 2 Sentences

Yesterday the 6th graders were writing the conclusions to the experiment: Does the amount of soil affect the growth of a plant?
I use a 5 part (at least one sentence in each part) conclusion format. This evolved from a much abbreviated form of the parts to a chapter in my dissertation. The parts are: 1. answer the experimental question, 2. state if the data did or did not support the hypothesis, 3. write about the data that supports your answer, 4. write about any confounding variables or ways you could have made the experiment better, and 5. give a new related experimental question.
I have the 6th graders right after lunch, so the 45 minute period is down to 40 minutes by the time they are seated and lab notebooks passed out. I award team points for the first teams seated, so they are getting better and hurrying along the slower members of their teams.
The first thing they had to do is figure out how much each plant grew. They had to subtract the final height from the starting height. This skill created a bit of a math challenge for a few - especially since they had not had negative numbers and some of their data indicated the plants had shrunk. Once all teams had  worked out all the plant heights they struggled to make sense of the data. No team had data that supported the hypothesis that more soil would cause the plants to grow taller. The hypotheses were not that 'sophisticated', though. Most of the hypotheses were 'the amount of soil will affect plant growth'. They eventually worked out that the amount of soil did affect plant growth as an answer to their experimental question. Then they had to pick which sentence fit their hypothesis: 1. The data did support the hypothesis; or, the data did not support the hypothesis. I imagine a few will have written both sentences in their lab notebook.
As they put their final periods on the second sentence the bell rang. Forty-five minutes were up, and only 2 sentences. "The amount of soil does affect the growth of a plant. The data did support the hypothesis."
But - 1 skill (calculating differences in measurements on a data table) and 2 concepts (analyzing data to write an appropraite answer to an experimental question and comparing data with a hypothesis). During a graduate course somewhere in my past I learned that on average a skill takes 45 minutes to teach and a concept 30 minutes.
I think I rushed the 6th graders yesterday, but it was just an introduction. We will have plenty of conclusions to write before the year is out.