Skip to main content

Cammaerts and Johansson Manage to ‘Replicate’ Danish Garden Cress Wi-Fi Experiment with even more Mistakes


Almost two years ago the shocking results of the ‘Danisch School Garden Cress WiFi Experiment’ went viral: six Danisch schoolgirls had shown that garden cress seeds placed next to WiFi routers germinated far more difficult than a control group without radiation. Especially the picures of a fresh green, unradiated, tray with cress next to a tray with sad looking brown results from a tray which had sat next to a router, looked very convincing. Foreign scientists were impressed by the schoolgirls’ experiment and said it should be replicted under better controlled circumstances. Two of those scientists recently published their replication of this experiment, but it is even more flawed than the original highschool experiment.

What the problems were with that school experiment I have laid out in Danish School Experiment with WiFi Routers and Garden Cress, Good Example of Bad Science. Maybe the most important flaws were the absence of blinding and  lack of control of environmental factors. For a schoolproject this would not have been that much of an issue, but the way this questionable result was misused, first by their science teacher and later by these ‘foreign scientists’, was quite bad. They used it to promote their unsubstantiated idea that electromagnetic fields from Wi-Fi and mobile phone antennas are far more dangerous than mainstream science and governments want us to believe.

Two of those foreign ‘experts’, the Belgian Marie-Claire Cammaerts and the Swede Olle Johansson, have joined forces in replicating this experiment. Apparently they succeeded in getting an article about their experiment published in the Argentinian journal Phyton, International Journal of Experimental Botany titled: Effect of man-made electromagnetic fields on common Brassicaceae Lepidium sativum (cress d’Alinois) seed germination: a preliminary replication study (December 2015).  The article itself can’t yet(?) be found on the journal’s website, but you can easily find in on several fear mongering websites (e.g. on What you can see on the website of Phyton however, is that its impact factor is just 0.117, not impressive at all.

It is no surprise that these researchers found shocking results once again: the cress seeds could not germinate at all under high levels of radiation, they state. And of course we get the pictures as well:

Fig. 2. Some representative images from the experiment. A: seeds after 7 days; B: seeds’ roots after 10 days; C: drawings of seeds after 10 days; D: seeds removed from their initial location and set under 2 μW/m2. Each time, for each image: a = seeds kept under 70 – 100 μW/m2, and b: seeds kept under 2 – 3 μW/m2.
Fig. 2. Some representative images from the experiment. A: seeds after 7 days; B: seeds’ roots after 10 days; C: drawings of seeds after 10 days; D: seeds removed from their initial location and set under 2 µW/m2. Each time, for each image: a = seeds kept under 70 – 100 µW/m2, and b: seeds kept under 2 – 3 µW/m2.

You would expect that professional researchers would be able to avoid all the mistakes that were made in the school experiment and that were pointed out by several people, not just me. Avoiding these mistakes is not that hard. But no, Cammaerts and Johansson succeed in doing an even worse job. I will just mention a few obvious points in which they outdo their highschool counterparts:

  • They call it a preliminary replication study, but the first thing you’ll notice is that they don’t work with Wi-Fi! In stead they state they have looked at the effect of GSM masts. Why should this be called a replication? Or do these researchers think that all radiation has more or less the same effect?
  • They only used two (2!) trays with seeds ‘nearby’ the radiation source and another two somewhat further away. Two per group is even less than the already not impressive number of six trays per group which the schoolgirls used.
  • Theys stopped the experiment already after ten days, whereas the school experiment lasted for thirteen days.

In the blog on the school experiment, I have pointed out that the germination of the cress is quite sensitive to environmental factors like temperature. A small difference could easily lead to a delay in germination of a couple of days. To control these environmental factors you’ll probably have to use a climate chamber like the one which was used in the research from Wageningen university on the possible negative effects of radiation on trees. Cammaerts and Johansson just write this about the setup of their experiment:

All the other environmental conditions were near-identical for each of the two double series of seeds (temperature = 20°C, humidity = 70%, luminosity ≈ 300 lux). The seeds were then observed after four, seven and ten days, and tap water was poured on the compost, equally for each series of seeds, at regular intervals.

This does not sound assuring. You get the feeling that they just left the trays with seeds on different places, not well observed, and only had a look at them once every few days.

The result itself is totally unconvincing. The abstract mentions: “the first step of seeds’ germination ‒ e.g. imbibitions of germinal cells ‒ could not occur under radiation.” What does this mean for all those ordinary people who effortlessly grow cress on the windowsills of their kitchens under similar or even higher leves of radiation?
The sources of radiation in the experiment were two GSM masts at a distance of about 200 meters. According to the authors these caused a level of radiation of 70 – 100 μW/m2 (about 175 mV/m). These levels are nothing unusual and maybe it would have been wise to take some radiation measurements at the production facilities of professional cress growers first. If there were any problems with germination due to these sort of levels professional growers would probably have noticed a long time ago.

Cammaerts is employed as a researcher at the Université libre de Bruxelles and she is also the main author of a probably fraudulent article on the effects of GSM radiation on ants (see Ants Performing Statistical Miracle under GSM Phone Radiation?). Johansson, in 2004 named as ‘Misleader of the Year’ by the Swedisch skeptics, is an assistant professor at the famous Karolinksa Institutet, but it doesn’t look like the institute is very happy with the quality of his research – recently he started a petition trying to gain support for his research and to protest against the budget cuts which have fallen upon his research.

Did you enjoy this article? Then please consider to support my blog with a donation.

3 thoughts to “Cammaerts and Johansson Manage to ‘Replicate’ Danish Garden Cress Wi-Fi Experiment with even more Mistakes”

    1. Had not seen this before, but this experiment is even worse than the original experiment of the Danish high school students, only 2 bowls are used. Meaningless.

Leave a Reply

Your email address will not be published. Required fields are marked * Your comment might stay in the moderation queue for some time, especially if it is your first comment on this site. Usually all comments will be published, even if they express extreme disagreement with my writing, but I suggest that you find another place to leave rude and offensive comments. Also completely anonymous and non-English comments are not likely to pass moderation. Also read the Privacy Policy.

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.