Cilantro is one of my favorite herbs. I’m part of the population that LOVES the flavor—not the portion that thinks it has a soapy taste! I grow a lot of my own herbs because the cost of one seed packet is comparable to a bunch or clamshell pack at the grocery store. For cilantro, I look forward to the shoulder season months because timing is the key to planting cilantro seeds. In this article, I will share tips on when and where to sow cilantro, how to know when to harvest, and slow-to-bolt varieties.
Cilantro is an annual herb that is part of the Apiaceae family, which is also called Umbelliferae (or referred to by the common name umbellifer). Other edible members of this family include parsley, dill, carrots, celery, and fennel.
As one of my favorite ingredients, cilantro has a presence in a lot of my favorite cuisine—Mexican, Thai, Indian, and more. One thing that may cause some confusion if you’re reading a cookbook or a gardening book from another country is that in North America, we refer to the plant as cilantro and the dried or crushed seeds as coriander. Elsewhere, the entire coriander plant (Coriandrum sativum) is referred to as coriander. When reading a recipe, be sure to check whether a recipe is asking for fresh leaves, or dried seeds or powder.
Planting cilantro seeds in the garden
Like dill, cilantro has a taproot, so it’s really fussy about being transplanted from a pot or cell pack. That’s why I direct-sow seeds outside in the spring.
Coriander aka cilantro seeds are actually the fruit of the coriander plant. They are called shizocarps. Once split in half, each seed is referred to as a mericarp. Most seed packets contain the shizocarps, so you’re planting two seeds as one.
Back to the planting part. Cilantro is shade tolerant, but make sure your garden gets at least six hours of sun. It also doesn’t mind average soils. However, I usually amend my soil in the spring with compost. You can also use aged manure. Plant your first crop as soon as the soil can be worked in early spring. I’ll plant mine usually in late March or early April. Plants don’t mind a touch of frost.
When planting cilantro seeds, make sure they’re covered by at least one quarter to a half inch of soil (.5 to 1.25 cm) because they like to germinate in total darkness. Space your seeds about two inches (5 cm) apart.
Thin seedlings if they grow too close together. Because the seeds are so big and I can plant each one individually (rather than those teeny tiny seeds where you have to just scatter them and hope for the best), I generally just plant what I need, so I’m not wasting seeds.
Where to strategically plant cilantro seeds
When it flowers, the nectar and pollen of a cilantro plant attracts a number of beneficial insects, including syrphid flies, parasitic wasps, and bees. In Jessica’s book, Plant Partners, she recommends planting cilantro seeds adjacent to your eggplants to attract predatory insects that will eat Colorado potato beetles and their larvae. You can also plant cilantro to control aphids around your cabbage crop.
Why succession planting cilantro seeds is smart
Because longer days and hot weather in the late spring eventually will cause your cilantro plant to bolt, the key to a continuous cilantro harvest is succession planting. After sowing your first seeds, wait a week or two and then continue planting more every couple of weeks. Cilantro is more of a cool-weather plant, so you may need to take a break over the summer. Wait until early September and resume your biweekly seed sowing.
You can start to harvest cilantro leaves when the stems are about six to eight inches (15 to 20 cm) long. And you can eat those stems, too! Cilantro plants are ready to harvest anywhere from 55 to 75 days after planting. Use sharp, clean scissors (I use my herb shears) to cut, taking about the top third of the stem.
How you can tell cilantro is starting to bolt
Unfortunately, cilantro can be a short-lived herb, especially if there’s a sudden hot spell. You’ll be able to tell it’s starting to bolt when the main stem starts to get very thick and those leaves start to get spindly and thin—almost like dill. The flavor starts to wane and eventually white flowers will form. Luckily there are varieties that won’t bolt as quickly. They’ll still bolt, but it will be slightly delayed.
Slow-to-bolt varieties of cilantro
I first bought a packet of Pokey Joe cilantro at a Seedy Saturday event from a company called Hawthorn Farm Organic Seeds because the first sentence on the packet read “Slow to bolt to seed.” This was good news to me. Since then, that’s my criteria when purchasing cilantro seeds. Other slow-to-bolt cilantro varieties include Santo Long Standing, Slow Bolt/Slo-Bolt, and Calypso.
If you let your cilantro go to seed, you can harvest the seeds as coriander. This video teaches you how: