Learn how to grow this fantastic herb to give your cooking a taste of the Caribbean!
Culantro (eryngium foetidum) is a tap-rooted biennial herb indigenous to continental tropical America and the West Indies. Although commonly used in dishes throughout the Caribbean, Latin America, and the Far East, culantro is relatively unknown in the United States and Canada and is often mistaken and misnamed for its close relative cilantro or coriander. Culantro also has medicinal value as a treatment tea for flu, diabetes, constipation, and fevers. One of its most popular uses is in chutneys as an appetite stimulant.
Culantro is thrives in the Caribbean sun. It is highly-nutritious culantro and easy to grow right at home no matter where you happen to live-if you have an indoor garden! By simulating short days you can keep Culantro in a vegetative / leaf-producing state so you can keep coming back for more!
Start with some quality seeds, the fresher the better-they do not store well. Be patient. Some seeds take longer to germinate than others. The average germination time for culantro is anywhere from 20 to 25 days, although I have seen my seedlings germinate in as little as 14 days by maintaining the substrate temperature between 75-80°F (24-27°F) with the use of a heating mat, a 3.5" tall humidity dome, and a thermostat (too much heat is no good for culantro's germination, though). Caribbeanseeds.com offers the best culantro seeds I have found. Their genetics and germination rate are simply unparalleled.
Culantro grows well in 10×20 nursery trays. If you are lucky enough to find some 10×20s with holes, put one on top of another one that doesn't have holes. That way, you can bottom-feed your plants by simply removing the top tray, flooding the bottom tray with an inch or two of nutrient solution, and then gently re-placing the top one inside your bottom tray. Do not use cell inserts! Culantro grows best when its roots are not limited by the cells' walls. A better method is to sow 50-100 seeds directly on the tray, on moist substrate. Do not cover with more substrate. Culantro seeds are tiny and covering with extra substrate will only lengthen their germination period. Because culantro does not transplant well, it is best to leave seedlings right on the spot where they germinate. Therefore, make sure that you spread your seeds evenly. A tray can hold a maximum of 85 culantro plants.
Soils & Substrates
Next on the list is your substrate. Although culantro grows in a wide variety of soils, it does best in moist, well-drained, sandy loams high in organic matter. You can use a variety of high-quality premium soilless mixes, but I like to keep my growing as controllable as I can, so I use a blend of mixed coir with a dash of perlite, for an approximate ratio of 3 parts coir to 1 part perlite. Coir makes a moist, well-drained medium for your plants' roots to grow, while providing a hostile environment for any possible pests. 2-3 inches of substrate per tray should suffice.
I have also thrown some seeds on a small rockwool cube. The culantro took a bit longer to take off, but now there is no stopping it! I can deduce then that culantro could be cultivated on shallow rockwool mats (for NFT/Ebb and Flow), or on leach tray-fitted slabs. Because culantro is a moisture-loving, perennial herb, the use of rockwool would certainly make for an economical option and worth exploring!
Pests & Diseases
Culantro is relatively pest / disease-free, but some growers report having seen root knot nematodes on plants that have grown for 2-3 years in box containers. A leaf spot problem which appears to be bacterial black rot (Xanthomonas sp.) has also been observed on such long-lived plants. I have yet to see these problems in coir (especially when supplementing with a bat guano-based actively-aerated compost tea, which acts as a natural nematocide), making fungus gnat larvae the only common occurrence in this grow medium. The diligent use of neem oil solution drenches will not only keep your medium pest-free, but the limonelles found in neem will impart a beautiful, vibrant green coloration to your culantro leaves. Neem soil drench is applied at a rate of 1 tbs/1qt water + a few drops of dish soap as emulsifier, followed by a filtered water flush 5 minutes after drenching, once every two weeks. It is the most natural and effective form of pest control I have yet to try. I highly recommend avoiding pyrethrin-based pesticides on culantro, as these tend to be too strong and will burn you culantro's prized leaves.
Researchers argue that, although culantro grows well in full sun, most commercial plantings occur in partially-shaded moist locations. Shaded areas, they claim, produce plants with larger and greener leaves that are more marketable because of their better appearance and higher pungent aroma. In a study on the effects of light intensity on growth and flowering of culantro, a significant delay in flowering and increased fresh weight of leaves were found in plants grown under 63% to 73% shade. Shaded plants also had fewer inflorescences with lower fresh weight. That being said, my personal experience will contradict most of these points. In an indoor setting, moist and shaded cultivation of culantro is an open invitation to pythium and fungus gnat larvae, which will invariably wreck your delicate seedlings. I have lost many culantro seedling trays by following the partial-shade guideline. Outdoor growing counts with limitless ventilation and alternate food sources for potential pests, which will make possible to grow culantro in the shade, with minimal pest damage (although this is relative to how healthy your outdoor area is). Indoor growers constantly struggle with maintaining adequate levels of ventilation, temperature, and lighting. In order to limit these variables, I grow my culantro under medium-intensity fluorescent lighting (~2000-2100 lumens at leaf level). The warmth of the bright lights keeps opportunistic larvae infestations and fungal rots at bay.
Culantro tends to bolt inflorescences (a group or cluster of flowers arranged on a stem) during longer days. These longer days also hinder leaf elongation and delay their harvest. Because of this, it is a good idea to keep your light cycles at 12-12. Any longer periods and prepare yourself to cut off culantro's spiny inflorescences; any shorter periods would wimp out your plants. But this is, once again, debatable by experience; I have grown culantro at 18-6 photoperiods and although growth was a bit delayed and bolting occurred after three months, post-harvest vigor was more than acceptable, and the extra hours of light helped the recently-harvested plants to re-vegetate faster than if kept at 12-12 cycles. When harvesting leave the three youngest leaves on each plant to encourage re-vegging.
Recent research at UVIAES has demonstrated that culantro can be kept in a vegetative mode through summer when treated with GA3 (gibberellic acid) sprays. Culantro tends to bolt and flower profusely under long day conditions; gibberellic acid 4% at 100 ppm concentration was found to be optimum for maximizing leaf production and minimizing flower growth. Researchers also recommend the use of slow-release fertilizers, such as Osmocote (14-14-14).
That being said, why on earth would you want to use gibberellic aid on a consumable crop? What good are higher yields if they are achieved indiscriminately and sacrificing nutritional content? I have purchased store-bought culantro in the past, and never did I find it to be up to my expectations. Its flavor and, consequently, nutritional content (as I have found) are greatly sacrificed in the commercial growing process. Personally, I'd rather have an ounce of my own culantro than a pound of store-bought "schwank-lantro". You can achieve comparable yields and healthier (not to mention tastier) herbs by using a combination of mineral-based hydroponic nutrients and actively-aerated compost tea. My nutrient regimen is quite simple: I use 1 tsp of 10-5-14, 100 ml of Pyrosol® (from a 3-tbsp/L H2O solution), and 3 tbsp of actively-aerated microbial tea. My 10-5-14 fertilizer provides mineral nutrients, Pyrosol® provides silica and trace elements (which enhance leaf integrity), and the actively-aerated microbial tea provides the beneficial microbes that aid in the breakdown and uptake of the elements necessary for plant growth.
As previously mentioned, these beneficial microbes also act as a nematocide. This is my basic nutrient solution; it is used at ¼-strength during the first 2 weeks after germination, at ½-strength from weeks 3-4, at ¾ from weeks 5-6, and at full-strength from week 7 onwards. I flush with plain, filtered water a week prior to harvest and revert to a ½-strength solution for the first two weeks post-harvest. After that, I go straight to full-strength until a week prior to second harvest, using plain, filtered water until it is time to harvest once more. This nutrient cycle is repeated constantly, as culantro will keep producing bountiful yields every 6-8 weeks after each harvest. The secret is to leave the 2-3 youngest leaves on each plant. They will quickly produce more. You can expect your culantro to be ready for harvest anytime after the 10-week mark, but leaving it longer will increase your yields.
Irrigate your trays often enough as to maintain the substrate constantly moist (not waterlogged). The more leaves on each plant, the more frequently you will need to irrigate.
Grow your own culantro; give your dishes a touch of the Caribbean. Happy harvest!
Published with gratitude to the grower and documenter, Eliab Lozada!