The 30-strong group of local and national campaigners opposed to genetic engineering set up the camp near Kirby Bedon in Norfolk last Saturday and plan to stay for about a month.
"Actions like this are the only way of bringing people together to voice concern and to say that something can be done to stop these experiments with life," said Paul Gill, one of the campaigners.
Charlotte Green, added: "We are trying to demonstrate in a symbolic manner alternatives to the massive use of pesticides and herbicides. We are showing ways of increasing soil fertility using organic methods."
Helen Morgan, a local activist, said: "Many people are concerned about the implications of these crops on our health and the environment, but as well as showing our concern, we are also discussing the alternatives.
"The site is going well. There is an information centre, organic gardens and lots of visitors," she added.
But Ms Green, 36, said they would not eat the vegetables they were growing in case there was a risk to their health.
She said the site is the work of a diverse group of people, some who have specialist knowledge of genetics and others who have learnt about the issue more recently.
"There are several genetics experts and others who have studied agriculture who have a lot of detailed knowledge," Ms Green said. "There are other people who are very alarmed about the lack of debate and public awareness of what is happening on open field sites.
"These are kept pretty secret. The companies have to put some kind of a notice in the local paper, but these can go largely unnoticed. Most local people didn't know that genetically modified crops were being grown in open fields.
"Greenpeace and the Women's Environment Network have been campaigning and lobbying about this for some time. People who have been following the subject have been making it their business to get information about it."
Although the protesters have been camping out for a week now, the group is not short of essentials, Ms Green said.
"We have a cafe here cooking wonderful meals. We get water from a local person. We have got pretty much all we need."
The idea for the "Genetix Crop Squat" came from members of Norfolk Genetic Concern and Action Against Genetic Engineering who are intent on raising awareness about the burgeoning number of these sites.
"The corporations developing these crops say they welcome public debate, but it has been too little too late," said Mr Gill. "These crops are in our fields now - therefore we must act now."Reuse content