How to do a real experiment in orchids
One of the most enjoyable things about growing orchids is the learning process. It’s also one of the most frustrating things as well. The pressure is even greater because we’re dealing with beautiful, treasured, (and oftentimes expensive) things that might live — or die — because of our choices.
I guess that’s why growing orchids is so addictive: it’s like gambling.
And in gambling, many “systems” abound. It’s the same with orchids.
So how do you figure out what works for you and what doesn’t? Answer: experiment.
While most of us know what an experiment is, not all of us know how to do a proper one that enables you to draw a strong conclusion.
Many well-meaning growers will rave about how switching to a new media/fertilizer/light source/etc revived a long-dormant plant, resulting in a blooming that caused AOS judges to swoon and give the plant an FCC. We’ve all heard (or told) stories just like this.
But the question is: how do you know this didn’t just happen by chance? The world is a very complicated thing, especially when it comes to biology. Weird, unexpected stuff happens all the time in experiments. And experiments performed on one single plant can always be attacked on the grounds that the observed result was due to chance, or some other unexplained phenomenon. The revival of the long-dormant plant could absolutely have been due to whatever change you subjected the plant to, but how do you prove causality?
That’s when you need a well-designed experiment. A well-designed experiment helps you to conclude that the results obtained were not due to chance.
Here are key steps to doing a solid experiment.
0) You need a control group and an experimental group. The control group is the one that is treated normally. No new media or fertilizer or anything. The experimental group is the one that gets the change in conditions that you’re trying to assess.
1) You need a “useful” number of plants to compare. A result from testing one plant is not enough from which to draw a strong conclusion. Ideally, you’d want something like 15 - 30 plants in each group (which is what professional plant researchers try to do). Of course, we don’t all have the space or resources to do an experiment on that many plants. For the typical grower, I suggest around six plants in each group. That means six plants in your control, and six plants in your experimetal group. (I know, I know…this requirement is NOT easy for most home growers.)
2) The plants should be preferably from the same cross. For example, if you’re testing a new media for growing rothschildianums, ideally you should use siblings from just one cross, such as ‘Rex’ x ‘Mont Millais’. But if you don’t have six from one cross, at least try to get six similarly-sized roths.
3) Focus on only one variable at a time. This is a hard one, and requires some self-discipline! If you’re testing a new fertilizer, don’t change the media as well. Vary only one variable in the experiment. Otherwise, your results will always be haunted by the specter of uncertainty of whether that one variable really caused, by itself, the result you observed.
4) Measure, measure, measure (and compare your control group to your experimental group). How many new root tips? How many new leaves grew? How much did leaves elongate? How much did the plants weigh? Measuring is objective, and banishes, or at least pushes back, subjectivity from the analysis. Yes, I know this is a pain, but the more of this stuff you do, the stronger and less assailable your conclusions.
Anyone who has read about orchids on the internet knows that advice and opinions abound. Doing proper, well-controlled experiments lets you cut through the crap and determine for you and your growing conditions what is likely to work best.