By Julie Riley, Cooperative Extension Service
In a quest for a cilantro least likely to bolt, I’ve grown 30 different kinds. Call me a slow learner. For the past three years, I’ve planted cilantro in July and had the same results.
Of all the varieties I could lay my hands on, Calypso was the least likely to bolt and send up a flower stalk prematurely. Bolting is what makes cilantro difficult to grow. It’s the same with spinach. Our long days lead to flowering and when the plants begin to flower, leaf production drops dramatically.
Popular in Mexican, Middle Eastern and Southeast Asian cooking, cilantro is an herb that must be eaten fresh. This amazing herb is cold tolerant to temperatures of 25 degrees and lower! Plant it now in your garden using space no longer occupied by early season crops you’ve harvested. If you purchased cilantro starts from a greenhouse this spring, your plants are probably already flowering. Pull them out and replant Calypso. If you don’t have any room in the garden and you’d like to give Calypso a try, plant in a container. You can even grow this variety in the house. Forget about varieties with names like Slow-bolt, Longstanding or cilantro without any variety name at all. All will bolt quickly.
Unfortunately, Calypso is not available from local seed racks but I am willing to share. I bought pounds of it this spring. Stop by the UAF Cooperative Extension Service’s Tanana District office for a free packet. We are located on the back side of the Fairbanks Community Food Bank at 724 27th Ave. The office is open Monday through Friday, 8 a.m. to 5 p.m., but closed for lunch between 1 and 2 p.m. Promise to limit yourself to only one packet, and I’ll leave seed under a flower pot next to the demonstration garden so you can stop by any time.
Many mail-order seed companies carry Calypso so if you like its mild flavor, you can add it to next season’s order. When shopping for cilantro seed online, you may come across the term monogerm. The round seed of cilantro is actually a fruit that contains two seeds. Some companies will split the fruit so that when both seeds germinate, they don’t emerge right next to one another.
For years I taught that thinning cilantro was important. One of horticulture’s basic principles is to give a plant enough growing space so that it doesn’t have to compete for water, nutrients and light. The first year of my cilantro trial, plants were thinned to 4 inches in rows spaced 1 foot apart. In the fall, after discussing spacing with the Master Gardener who helped with data collection, we decided plants needed more room to grow. One Calypso plant measured 14 inches across at the base. Over the winter I pondered how cilantro should be grown and the second year, planted two weeks later and spaced plants closer at 2 inches apart.
Year three, the final year of my study, I used both mid-season and late July seeding dates and spaced plants 2 inches and 4 inches apart. While waiting for July to roll around, I planted another bed for fun using a wide row planting technique. I planted solid and did not thin. Commercially, cilantro is harvested by making bunches in the field cutting leaves either 1 inch above or below the ground. I cut off leaves at 1 inch above ground and from approximately 4 square feet, harvested 10 bunches that were the size you’d find in the grocery store. I let the wide row regrow, harvested and then let it regrow again before harvesting a third time. A total harvest of 30 bunches from the same area, amazing! This is now how I teach growing and harvesting cilantro.
Remember cilantro’s tolerance to cold temperatures. Last spring I planted Calypso seed in late April in a window box on my deck. Leaves were ready to harvest June 5, 36 days after planting. If you have a hoop house or greenhouse, experiment with planting dates. Calypso could become the last crop you harvest in fall and the first you harvest in spring.
Julie Riley is the horticulture agent for the University of Alaska Fairbanks Cooperative Extension Service in the Tanana District office. She can be reached at (907)474-2423 or firstname.lastname@example.org.