I’m a big fan of making Mexican food, specifically fresh guacamole, so when I was planning out my garden for this year I was sure to make space for cilantro, an herb that is frequently used in Mexican and other Latino dishes. This was my first experience growing cilantro so I was unaware that bolting–when a plant uses all of its energy to make seeds rather than continue growing, this usually happens when the weather is warm–was a common problem with the herb. Apparently, cilantro, like humans, prefers to remain at room temperature (somewhere between 68 degrees and 74 degrees). Once cilantro feels the temperature rising, it bolts, and seeing as how New York has hot, muggy summers, my cilantro was destined to bolt early. Luckily, the seeds/fruit that cilantro produces after it bolts is another common herb: coriander, so all is not lost when your cilantro bolts.
After the jump, find out how to collect coriander seeds and tips on growing cilantro.
You will know your cilantro is beginning to bolt when it starts producing delicate leaves (not like the fat, dark green leaves commonly used for cooking) and starts to grow tall (Fig. 1). As you can see, the plant gets very tall, almost two feet in height! The more common cilantro leaves will begin to turn yellow and pink and these leaves have now become inedible.
Eventually the cilantro plant will produce delicate white flowers (fig. 2) which are great for attracting bees and other pollinators to your garden. You still have another month or so to go until you can collect the coriander seeds, so be patient!
Eventually, seeds or fruit will form and the flowers will fall off (fig. 3). They will eventually turn a paper bag shade of brown and the stems will become dry and brittle (this usually takes a few weeks to a month). Now your coriander is ready to be collected. What I normally do is dig up the entire plant and snip off the stems with the coriander seeds, leaving about five inches or more from the seeds. Then, I get a large container (I use a yogurt container, but a baking dish or pan would work fine), hold the stems with the seeds facing down towards my collecting container and put my thumb and index finger behind the seed. When you gently squeeze or pinch the section where the seed meets the stem, the seed will pop off and (hopefully) go into the container. It can be a long process, depending on how many coriander seeds you have, so take your time.
When you have all your seeds ready you should try to remove the chaff as best you can. I like to move the seeds from one cup to another in front of a gently blowing fan and let the chaff fall on a newspaper below me. You can also roll the seeds on a piece of paper and just pick up the seeds from the chaff. Once you have done this, I like to spread my seeds on a piece of white paper to let them thoroughly dry: if your seeds go into storage moist they are subject to mold. After that, collect the seeds and put them in an airtight container–like an old spice bottle or a baby food jar–and save them in a cool, dark place.
You can use your coriander for cooking–they go great in a lot of Mediterranean and Indian dishes and they are also often used when making sausages–or you can try to grow cilantro from the seeds when the next spring comes around. Depending on where you got your original cilantro from, the seeds might not produce a plant like the one you got your seeds from. However, it is worth a try to see how the seeds come out.
If you want to keep your cilantro from bolting you can try to prune the flowers once they appear to keep the plant growing (a trick that often works well for bolting basil) but cilantro has a pretty short life span. If you live in a warm climate, you can sow cilantro seeds every six weeks and keep your plan indoors (facing a sunny window, of course) to ensure a long supply of yummy green leaves. In my experience, cilantro doesn’t preserve well and few dishes call for dried cilantro so you are better off continuing to grow the annual plant indoors if you have a real craving.