Behind the fence at Tikkun Olam -- Hebrew for "fixing the world" -- the green-fingered staff say they have created an Israeli first, by breeding a cannabis plant almost free of THC, tetrahydrocannabinol, the substance that gives smokers their high but can also carry a serious downside.
The hash with no high also removes a psychological barrier for those who could benefit from its properties but are loath to use standard marijuana, even with the blessing of the Israeli health ministry.
"We managed to isolate the molecules of THC and CBD," said Mor Cohen, head of the growing facility on the edge of the Galilee town of Safed, referring to cannabidiol, another component of cannabis, which can help ease symptoms of diabetes and some psychiatric disorders.
While the small family-based firm has developed a variety which is over 99 percent CBD, it has also cross-bred it with other varieties to give plants with different mixes of the two ingredients, aimed at helping patients with differing needs.
Getting the balance right, they say, can ease pain and stimulate appetite, while reducing or eliminating unwanted effects.
"We have accumulated experience in treatment of some 2,000 patients with varying symptoms; some with pain, others with constipation, dizziness or nausea," Cohen told AFP inside a vast tented enclosure with row upon row of plants giving off a heady, sickly sweet perfume.
"We know how to provide a solution, whether it's for Parkinson's disease, for cancer, to increase appetite, problems of insomnia related to post-traumatic stress disorder... for each and every illness."
"THC is the substance that stimulates appetite," said Tzahi Klein, head of development. "CBD acts differently. For some people THC has unwanted effects, (but) CBD reduces the psychoactive activity of the THC.
"We have a range of plant varieties from full THC to a very high proportion of CBD, and we can suit the relative percentages to different patients."
The Hebrew term Tikkun Olam refers to a Jewish tradition of seeking to make the world a better place through prayer and good deeds.
The firm's logo includes a verse from Psalm 118 which says: "This is the Lord's doing; it is marvellous in our eyes," flanked by a marijuana plant within a six-pointed Star of David.
To discourage unwelcome visitors, however, the site is secured behind high fences protected by armed guards. And the buildings bear no identifying marks.
In a small but spotless packing room reminiscent of movie depictions of a dealer's apartment, large plastic bags of dried marijuana are piled next to a set of scales, waiting to be packed into 10-gramme "baggies," as Tikkun Olam calls them, for distribution to patients holding a doctor's prescription.
For those unskilled in rolling their own or physically unable to do so, two lab-coated women stand in a corner rolling elegant cigarettes of chocolate brown paper with shiny gold tips.
"We find this service very useful to patients," Cohen says.
Only 100 percent organic nutrients are used for the plants, and light is from the sun, says Klein, adding that cannabis, as an alternative to synthetic medicines, is green in more ways than one.
"The use of cannabis reduces the use of other medicines... medicines which pollute the environment, which we know are polluting water systems," he told AFP.
Information Minister Yuli Edelstein, while supportive of medical marijuana in general, and the work of Tikkun Olam in particular, says the government is not considering blanket legalisation of cannabis use.
"The new thing here is that what has always been thought of as just a drug, a negative thing, has become -- through the good work of the growers here -- a medicine which is fact not a narcotic," he said on a visit to the site.
"We are not dealing at the moment with the legalisation of marijuana."
According to figures published earlier this year by Sheba Medical Centre and the Israel Cancer Association, medical marijuana has been approved for use by about 6,000 Israelis suffering from various illnesses.