Cilantro Gardening – New Grower’s Troubleshooting Tips

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Paul has a two-acre yard on red clay soil in Southeast Texas. He knows exactly what the challenges are to nurturing a thriving yard in difficult soil.Paul takes a practical approach to yard improvement and enjoys putting best practices and “golden rules of lawn care” to the test.

Why Cilantro Won’t Germinate

Under the right conditions, cilantro will germinate within 7-21 days. However, there are instances when the cilantro seeds fail to germinate, even if you leave them in the soil for longer.

There are several reasons why your cilantro won’t germinate:

Cilantro seeds were planted too deep. Oxygen is necessary for seed germination. When seeds are planted too deep, the seeds are denied the oxygen they need to grow. The ideal depth is ¼ to ½ inches (0.63cm-1.27cm).
High soil temperature. Cilantro is a warm-season plant. However, they’re sensitive to soil temperature that’s too high. The ideal soil temperature for cilantro seeds is 64-75°F (18-24°C). Mid to late spring is the ideal planting season. Alternatively, you can plant in early fall when the temperatures start falling.
Poor quality seeds. The age of the seeds can be a problem, especially if you have had the cilantro seeds for a long time. If the seeds were past their used-by-date, this could be the reason the seeds failed to germinate.
Overwatering. Moisture is important for seed growth and for cooling the soil’s temperature. However, when you overwater the cilantro seeds, they’ll rot. If after three weeks the seeds don’t sprout, dig some out. If they’re rotten, you can sow again. Only this time, keep the soil moist, not saturated.
Seeds fail to break the seed coat. Cilantro has two seeds enclosed in the hard coat. Sometimes the seeds break the coat without help. However, some fail to break the seed coat. Soaking the seeds 2-3 days before planting will soften the coat and increase the germination rate.

Why Is My Cilantro Plant Wilting?

Cilantro loses most of its moisture through its leaves. Drooping leaves is a sign your cilantro plant is wilting. Since the cilantro plant has plenty of leaves and a large surface area, the moisture loss, if not controlled, will cause it to start wilting.

Your cilantro plant may be wilting because it’s losing more water than it’s getting. A small container has a lower soil capacity, so it loses moisture faster than a larger one. Additionally, fast-draining soil and high temperatures will cause cilantro to wilt.

In some cases, cilantro will wilt temporarily as a defense mechanism. When it’s too hot, it may wilt in an attempt to conserve water. It may appear to be dying, but the leaves will unfurl as soon as the temperatures fall. Watering your cilantro regularly will prevent wilting.

Why Are My Cilantro Leaves Turning Red?

When cilantro leaves turn red, you should be concerned. Multiple factors may have contributed to the red color of your cilantro.

Your cilantro leaves turn red when the soil lacks phosphorus. Insect infestation, plant diseases, soil compaction, and some herbicides affect the plant’s ability to absorb phosphorus. Acidic soil has less phosphorus. Incorrect soil pH also affects root growth, resulting in low phosphorus uptake.

Soil testing will help you analyze the phosphorus levels in the soil. Adding lime to the soil will reduce its acidity. Pest control and the use of organic disease treatments will help prevent phosphorus depletion in the soil.

How Do You Fix Overwatered Cilantro?

Some of the signs of overwatered cilantro include:

Yellowing leaves
Mildew
Stunted growth
Soft and stems and roots
Dead, blister-like cells on the underside of the leaves

When you have overwatered cilantro, you need changes in the care of your cilantro.

You can fix overwatered cilantro by creating more drainage holes in the pot holding your cilantro to allow the soil to dry out much faster. Avoid watering your cilantro until the soil feels dry, but it shouldn’t be too dry. You should also remove all dry and dead leaves to allow for new growth.

Unfortunately, there’s no guarantee that your overwatered cilantro will bounce back. However, you won’t discover the extent of the damage if you don’t take measures to help revive it. You should expect changes in your cilantro within a week. If there’s no change or your cilantro shows signs of dying, extensive root rot may be the problem.

How Do You Revive Cilantro That Looks Like It’s Dying?

Yellowing leaves and drooping stems are signs your cilantro may be dying. Before you attempt to revive your cilantro plant, you need to find out what went wrong.

You can revive dying cilantro by watering the cilantro more often if underwatering is the problem. If overwatering is the cause, avoid watering your cilantro until the soil dries. Add sawdust to absorb excess nitrogen from the soil. Place the pot under partial morning sun and afternoon shade.

Identifying the reason behind your dying cilantro is critical since the wrong action may worsen a bad situation. For example, you may assume that underwatering is the problem, yet the problem may be overwatering. Instead of reviving your cilantro, you may end up killing them.

Is It Better To Grow Cilantro Inside or Outside?

Cilantro can be grown indoors and outdoors. When deciding which option is ideal, you need to consider:

The space available
How much cilantro you need
The time you can spare to care for the cilantro

It’s better to grow cilantro inside for regions that experience harsh summers. Pests and diseases are also easier to manage when growing cilantro inside. However, the plant needs at least 6 hours of direct sunlight to thrive. If you don’t have grow lights, it is best to plant cilantro outside.

Cilantro grown outside needs more care, especially if they lose moisture quickly due to high temperatures. If you cannot water the plants regularly to make up for the lost moisture, you should plant cilantro inside.

What Are the Best Conditions for Growing Cilantro?

Most of the problems new growers encounter with cilantro are connected to poor growing conditions. Whether you’re growing cilantro indoors or outdoors, you need to make sure the conditions are ideal for healthy growth.

The best growing conditions for cilantro include temperatures of 50-85°F (10-29°C), well-drained soil, and regular watering during germination. Established cilantro doesn’t need much water. Areas with partial sunlight and shade are ideal for optimal cilantro growth.

Indoor and outdoor cilantro demand different growing conditions. However, aspects such as watering, soil conditions, and temperature are constant. Since indoor plants don’t lose as much moisture as outdoor cilantro, well-drained pots will help prevent root rot and fungal diseases (source).

This video offers tips on how you can successfully grow cilantro, and the ideal conditions for growth:

How to Grow Cilantro...And Stop It From BOLTING!

Watch this video on YouTube

Cilantro Pests and Diseases

Cilantro, like other plants, is susceptible to pests and disease. Sometimes, the growing conditions contribute to pest and disease infestations. However, in some cases, you may have no control over the pests and diseases that attack our cilantro.

The common pests and diseases that attack cilantro are:

Bacterial blight
Powdery mildew
Soft rot
Damping-off
Carrot Motley Dwarf disease
Aphids
Spider mites
Beet armyworms

Bacterial Blight

Bacterial blight in cilantro is often transmitted through the cilantro garden by:

Pollinator insects
Infected seeds
Moving machinery

Symptoms of bacterial blight are:

Black or brown spots
Seeds won’t germinate
Marks on the stem
Yellow and brown leaves
Dark and shriveled seeds

Unfortunately, severely affected cilantro may not survive after a bacterial blight attack. However, you can prevent bacterial blight in cilantro by:

Testing the seeds before planting
Treating infected seeds in hot water 270°F (132°C)
Going for drip irrigation instead of overhead irrigation

Powdery Mildew

Powdery mildew is a fungal disease that affects the appearance and flavor of cilantro plants. Overwatering and moisture retention are the main causes of this disease.

Common symptoms are:

White coating on cilantro leaves
Fluffy growth
Dropping leaves
Discolored leaves

You can control the spread of powdery mildew in the following ways:

Use a garlic and water solution on the cilantro leaves.
A water and baking soda solution will alter the leaves’ pH and will subsequently prevent fungal growth.
Apply neem oil on affected cilantro plants.
Avoid wetting the leaves when watering.
Avoid watering cilantro in the evening.

The Harris Neem Oil (link to Amazon) is great for organic gardening, specifically, disease control. It’s easy to use and will have no negative effects on your cilantro.

Soft Rot

Soft rot is an opportunistic disease that attacks damaged cilantro tissues. High humidity and high temperatures contribute to the prevalence of soft rot in cilantro. Infected soil, plant debris, and garden tools cause the spread of soft rot in your cilantro plants.

Symptoms of soft rot include:

Mushy and brown tissues
Water-soaked spots at the petiole base
A bad smell from the rot in the petioles

Unfortunately, soft rot has no treatment. If the damage is extensive, you may need to uproot and replant the cilantro.

You can control the spread of soft rot by:

Removing infected parts as soon as you spot them.
Not adding cilantro with soft rot in the compost.
Not overcrowding the cilantro. If your aim is the cilantro leaves, plant them 2 inches (5cm) apart. However, if you are growing cilantro for the coriander seeds, they should be 20-30 cm (8-12 in) apart.
Avoiding over-watering the plants.
Disinfecting your garden tools regularly with alcohol and bleach.

(Source: Utah State University Extension: Horticulture: Cilantro/Coriander in the Garden)

Damping Off

Damping-off is a fungal disease common in cilantro grown indoors. It mainly attacks newly germinated cilantro plants and seeds. Overcrowded seedlings and seeds encourage the growth of fungal spores.

Symptoms include:

Red spots in germinating seedlings
Rotting seeds
The sudden collapse of cilantro seedlings
Yellowing stalks and leaves

You can control damping-off by:

Planting in well-drained soils.
Avoiding overcrowding of cilantro plants and seeds.
Using high-quality seeds.
Disinfecting garden equipment.

Carrot Motley Dwarf Disease (CMDD)

The Carrot Motley Dwarf Disease is a viral disease caused by carrot red leaf virus and carrot mottle virus. Although cilantro isn’t the host of this virus, if you have carrots in our garden, they can infect your cilantro with CMDD.

The primary symptoms of CMMD are stunted growth and discolored cilantro leaves, usually red, yellow, and orange.

Avoid planting cilantro close to carrots or in soil that was previously used for carrots.

Aphids

Aphids are small insects that drain the sap of plants like cilantro. If their infestation isn’t controlled, they’ll destroy your cilantro.

Signs of aphids in cilantro include:

Dark spots on cilantro leaves
Yellowing and browning leaves
Stunted growth
Sooty mold growth

Fortunately, you can control the spread of aphids in several ways. They include:

Pruning the affected parts.
Using neem oil, insecticidal soap, or canola oil for mild infestations.
Spray washing the aphids.
Planting spinach, beans, and peas near cilantro that will help repel aphids, whiteflies, and spider mites.

(Source: University Of California Agriculture and Natural Resources: Herb Gardening)

Spider Mites

Spider mites are rare in cilantro because they detest its scent. However, they sometimes find their way into cilantro. Some of the signs include webbing and black or red spots on the leaves.

Washing your cilantro with pressure spray from your hose will help get rid of spider mites.

Beet Armyworms

Beet armyworms are moths, brown-colored, that tend to attack cilantro in late summer and fall. They thrive in warm weather, and they tend to affect cilantro leaves most.

Signs of beet worms include:

Large larvae on the petioles
Stunted growth of emerging buds
Holes in the leaves

You can control the spread of beet armyworms by spraying neem and other insecticides.

Conclusion

Growing cilantro can be a challenge, especially if not grown in the ideal conditions. Fortunately, these plants are fast-growing and mature within 45-70 days. Pests and diseases aren’t common in cilantro grown indoors, but they can be an issue in the garden. Timely intervention when pests and diseases attack your cilantro will help prevent extensive damage to your plants.

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