Cilantro in hydroponics

Like many herbs, cilantro (Coriandrum sativum) is native to the Mediterranean area but has been spread wide across the world. Today, the herb is prominent especially in Asian and South American cooking.

The spice coriander is the seed of cilantro, although the two do not taste similar. The name “coriander” can be confusing since some people call both the green and the seed “coriander”.

Cilantro is notorious for a polarized fan/enemy base. Most people will experience either a cool, fresh taste or an unpleasant soap taste. If you’re in the first group, cilantro is a lovely addition to dishes both as a garnish and a main ingredient. If you’re looking for an experimental recipe, one of the easiest ways to try cilantro is as part of a salsa or as a topping on a curry.

Cilantro and its seed – coriander – have been used medicinally by cultures across the world for millennia.  

A member of the family Apiaceae, cilantro shares traits with parsley, carrots, and dill. Like those crops, cilantro bolts a slender flower stalk with flat flowers, and self-seeds easily in horizontal growing.

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While cilantro is an easy crop for soil gardeners, indoor and hydroponic growers may not get the highest space use efficiency from this crop. A longer turn and limited yield means that cilantro growers can see opportunity costs from growing something more productive. On the other hand, this herb is low-maintenance. If growers are sure that they can get good pricing (do your in-person market research!), cilantro can still be a good crop.

Since it’s small-statured, cilantro can be grown in almost any hydroponic system, so long as pH and EC ranges are appropriate.

Ideal conditions

• EC: 1.6-1.8
• pH range: 6.5-6.7
• Temperature: 40 – 75 ºF

Cilantro can be a tricky crop to grow since it bolts very easily, especially in hot conditions. This crop prefers cooler temperatures (40-75º Fahrenheit) and low salts. The preference for cool temperatures extends to germination as well; temperatures in the 60’s will result in higher germination rates than germination environments in the 70’s or 80’s.

If bolting is triggered, trim the bolts and adjust environmental conditions. Be aware that the flavor of the greens becomes more bitter and harsh once the plant has bolted. Growers can purchase slow bolting seeds to minimize the potential for crop failure.

Common pests

Two of the most common diseases of cilantro in hydroponics are bacterial leaf spot and powdery mildew. Bacterial leaf spot causes yellow spots on the leaves and is usually caused by too much moisture around the leaves or high humidity in the growing environment.

Powdery mildew is a common indoor pest that affects a wide range of greens and herbs and is symptomized by a powdery white film on vegetation. If you struggle with powdery mildew, be sure to keep the environment in the proper temperature range. As soon as you notice a powdery mildew outbreak, remove the affected vegetation. Some sprays can help as well; see this article for more information on controlling powdery mildew.

Like most crops, cilantro is vulnerable to Pythium. Pythium can become problematic in systems with inadequate aeration around the roots.

Timeline & harvesting

Cilantro seeds germinate in 7-10 days, with leaves ready to harvest 40-48 days (5 ½ – 7 weeks) later. From seed to harvest, cilantro takes 50-55 days.

Cilantro can be harvested fully or partially, requiring very little maintenance like trimming. If using a partial harvest, the first harvest will take place at about 5 weeks after transplant and the second at about 8 weeks after transplant. The second harvest will be lower than the first. (Our trials yielded 3-4 and 2-3 lbs respectively.)

Cilantro may be packaged various ways depending on the farmer and (even more importantly) market preference. Common packaging options are 0.75-1.0 oz clamshells or 1-2 oz. bunches. 

After purchase, consumers are advised to store their cilantro in the fridge. Keeping the cilantro in a glass of water like flowers can help extend shelf life.

Retail pricing for cilantro in grocery stores typically ranges from .33-.99/bunch. Given that your cilantro is likely locally grown and marketed and assuming that one bunch is 0.75-1.0 oz., local cilantro pricing could range from $0.5 – $2.0/oz.

Choose your crops!

To choose a crop set, you need several crops with overlapping pH, EC, and temperature preferences. You can get all of this information in the Recommended Crop List, a list of crops that excel in ZipGrow Towers.

Build your crop set today: