Kandahar Giant Cress
Origin: Kandahar, Afghanistan
Improvement status: Cultivar
Seeds per packet: ~30
Germination tested 12/2020: 76%
Life cycle: Annual
NEW EFN INTRODUCTION. Of all the seeds we've "liberated" from the obscurity of our government's genebanks, this is one of our absolute favorites — and not least because it began as a mystery and still remains quite mysterious, though we have come to appreciate its known virtues a great deal. It likely will never be a staple crop, and it's certainly not for everyone, but we are very excited to be offering it here for the first time.
In 1954, a USDA "agricultural explorer" by the name of E.E. Smith visited Afghanistan. He must have collected thousands of seeds, because over 700 of his accessions can still be found in the USDA collections more than half a century later. He collected everything from barley to hemp to watermelons, along with crop wild relatives (including many grasses) and obscure crops unknown outside of Afghanistan. EFN co-founder Nate Kleinman noticed a mysterious entry in the USDA's database among the hundreds of E.E. Smith collections: a plant called "Shalgham" and listed as "Lepidium spp." (which means "undetermined species in the genus Lepidium"). It had only been classified thusly for a few years, after being misidentified in the collection as Thlaspi arvense (field pennycress) for decades. Nate was interested in the Lepidium genus after frequently encountering Lepidium sativum (Garden Cress) while living in the Netherlands, where tiny cardboard trays growing cress sprouts are sold in supermarkets across the country. Dutch people snip off the tops and add them to salads, sandwiches and soups for a spicy kick. The flavor is similar to wasabi. Nate's interest was also piqued by that local name, "Shalgham," which some quick research revealed is the Pashto word for "turnip," so he thought this might mean the mysterious "shalgham" might turn out to be the only other species in the genus Lepidium other than South America's famous maca (Lepidium meyenii) to grow a tuberous root.
When the seeds arrived from the North Central Regional Plant Introduction Station in Ames, Iowa, the information printed on the envelope indicated that the plant had not been grown out since 1991, more than twenty years earlier. We planted a couple hundred seeds and only seven sprouted. If we had waited just a few years, those seeds might all have been dead. While we were eager for them to produce tubers, they did not oblige. Instead, they developed into a plant that is a dead-ringer for garden cress, only three or four times larger. The leaves are up to 7 or 8 inches long, and slightly fleshy compared to their smaller cousins. The flavor is similar, if a bit stronger. And the basic form and structure of the plant is also similar. We grew some standard garden cress the same year, in order to compare the two, and found that the shalgham seemed to be taking its sweet time going to flower. Standard garden cress bolts within weeks of planting. This shalgham waited a couple months, flowering easily two or three weeks after the regular garden cress. It also produced a very tall flower spike, two or three times the height of its cousin's, and with many more flowers and seeds.
It was the giant flower spike that gave the plant away (most likely): while we can't be certain without a great deal more research, it seems quite apparent that this is a strain of cress — possibly even the same species as garden cress — bred to be an oilseed crop! There's a history of garden cress seed oil being used for food (and it is currently under a great deal of scientific study for its nutritive effects, various medicinal properties, and possible biofuel use). Plus, oilseed use may explain the conflation of the word for "turnip" with these seeds: for "turnip" is the same species as "mustard," and mustard is a very common oilseed in Afghanistan. So when E.E. Smith collected it in the market, the seeds may have simply been mislabeled as "shalgham," or (just as likely) someone told him the seeds were "shalgham," or "used like shalgham," and he simply recorded "shalgham" in his notebook. In any case, we've decided to rechristen it "Kandahar Giant Cress," because it's clearly cress, it comes from Kandahar, and it's huge.
We have had difficulty getting a seed crop from this plant, after our first trouble-free year (with just the seven plants). If the weather is rainy or it is too humid when the plant goes to seed, the flower spikes and ripening seed have been attacked by some sort of whitish mold. In 2019 we finally got a sizable crop by growing it at Nate's farm in upstate New York, in a well-ventilated spot, apparently at just the right time. Our friend and associate Michal Slaby has also managed to get small seed crops at his home in the mountains of northern New Jersey, making sure we had enough to keep up our larger-scale efforts. We can't wait to grow loads more of it so we can press at least a little oil and start exploring its uses.
We are offering a limited supply of these incredibly rare seeds in order to ensure that this plant starts getting around. After sitting in a freezer in Iowa for decades, it's time for this shalgham to spread its wings.
GROWING TIPS: Direct seed in prepared ground after danger of frost has passed. Space plants at least 6 inches apart for maximum leaf size, or farther for maximal seed production. Plant in a well ventilated area if possible, to avoid mold issues.