Cilantro does not need full sun to grow, but it does need a few hours of direct sunlight every day to remain healthy. It is a heat-sensitive plant that thrives in cool-to-warm climates. For this reason, gardeners should avoid placing cilantro in areas where the intensity of the afternoon sun hits the plant for several hours. UV radiation is strongest between 11:00 and 2:00 in the afternoon and cilantro leaves are prone to burning under this kind of harsh sunlight.
Cilantro is the name given to the leaves of the Coriander plant. However, the term coriander can be correctly used to describe the stems, leaves, seeds, or any other part of the Coriander plant.
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How Many Hours of Sun Does Cilantro Need?
Cilantro grows well when it receives four to six hours of direct sunlight each day. However, cilantro prefers pleasantly warm temperatures between 65–75℉ (18–24℃). When cilantro becomes stressed due to heat, it will start bolting and sprout white flowers. Snipping white cilantro flowers won’t stop the bolting process or restore flavor to leaves. The only action a gardener can take when cilantro bolts is to let the blooms go to seed.
- Cilantro thrives on 4–6 hours of direct sunlight per day.
- Your cilantro will retain its flavor when grown in temperatures 65–75℉ (18–24℃).
- CIlantro exposed to too much heat will “bolt,” which causes it to flower and die.
To help prevent bolting when temperatures rise above 80 degrees, water cilantro plants when the soil surface feels crumbly and dry. Keeping soil moisture levels optimal for cilantro growth reduces the risk of early bolting and heat stress.
Can Cilantro Grow in Indirect Sunlight?
Cilantro can be grown indoors throughout the year as long as containers receive partial or indirect sunlight for at least 10 hours per day. When you plant cilantro indoors during the summer, make sure to move containers away from areas where full sunlight falls on the plant after penetrating window glass. The transparency of glass transforms sunlight into pure heat that has nowhere to escape. Therefore, cilantro or any other heat-sensitive plant sitting near a window receiving direct sunlight during hot weather is at risk of suffering heat stress.
- Cilantro can grow in indirect sunlight.
- Provide at least 10 hours of sunlight (mixed direct and indirect) each day.
- Add ammonium nitrate to the soil when growing cilantro indoors—this will encourage healthy growth.
When cilantro is grown indoors or outdoors where it doesn’t receive full sunlight, it’s best to mix half a teaspoon of ammonium nitrate per square foot of soil. Fertilizing cilantro planted in an outside garden should only be done twice during its growing season. While fresh, high-quality potting soil does not need to be fertilized, cilantro planted in gently used potting soil should be invigorated with a nitrogen-rich fertilizer.
Can You Grow Cilantro in Shade?
Cilantro will tolerate some light shade, but it’s best to grow cilantro in sunny areas. If you live in an area where midday sun brings extreme heat, it’s acceptable to provide some partial afternoon shade for your cilantro. By partially shading your plant during the hottest part of the day, you can prevent cilantro from bolting and dying. This will ensure you have fresh cilantro for cooking.
- Cilantro will tolerate partial shade.
- Use partial shade to protect cilantro from heat in sunny regions.
- Cilantro cannot be grown in a fully shaded area.
Cilantro, like other herbs and vegetables, requires sunlight to complete photosynthesis. Parasitic and saprophytic plants are the only true plants that do not need sunlight to develop, but cilantro is not an herb for shade. With that being said, you will want to make sure your cilantro plant is not shaded during the day.
What Happens if Cilantro Doesn’t Get Enough Sun?
Without the ability to access sunlight for photosynthesis, your cilantro crop will essentially starve from a lack of essential nutrients. When cilantro doesn’t get enough sun, it loses the immunoprotective properties provided by photosynthesis, making it susceptible to one or more of the following diseases:
Leaf Spot
Signs of leaf spot include small yellow lesions on leaves that gradually turn brown. Lesions often merge into one, large lesion covering a single leaf. At this point in leaf spot disease, cilantro leaves feel thin and dry. In some cases, leaf spot occurs because the seeds were originally infected with the Pseudomonas syringae pathogen. When cilantro receives enough sun but suffers leaf spot, it’s likely due to planting infected seeds.
Soft Rot
A bacterial disease causing soft, brown lesions to appear on leafstalks, soft rot thrives when plant tissue is deprived of oxygen. Excessively wet soil coupled with a lack of sunlight facilitates the development of soft rot in coriander plants.
Additionally, lack of sun combined with soil that remains unwatered and dry for too long could significantly decrease cilantro leaf yields, encourage bolting, and further promote disease.
Can Cilantro Get Too Much Sun?
Cilantro thrives in full sun as long as it doesn’t experience intense heat from the midday sun. In warmer climates, cilantro planted in outdoor gardens should be shaded to prevent bolting, burned leaves, and heat stress.
The best material for protecting cilantro and other heat-sensitive plants from excessive sunlight is cheesecloth, a gauzy, loosely woven cotton cloth that won’t harm plants. Cheesecloth’s white or creamy color effectively reflects sunlight so that cilantro plants remain cool and refreshed.
Protect young coriander plants with a plastic container (a clean cat litterbox, laundry basket without holes, etc) that can be placed over fragile cilantro seedlings when the sun is strongest in the afternoon.
How Much Sun Should Cilantro Get?
Cilantro needs at least four to six hours of sunlight each day to develop normally. However, when possible, cilantro plants should avoid receiving sunlight between 11:00 am and 2:00 pm, when UV rays are at their strongest. Cilantro prefers temperatures between 65–75℉ (18–24℃) as long as it isn’t too humid. Cilantro grows in a variety of soil standards but prefers fertile, well-draining soil with a pH between 6.5 and 7.5.
