How to Protect Your Cannabis Seedlings From Damping Off?

Imagine this: you are growing a batch of ten cannabis seedlings and out of nowhere, some of them lose their vigor, drop to the ground, and die. The next day, a few more seedlings lose their lives, and before you know it, all ten seedlings are dead. Your project came to an end even before it started properly. 

What could cause this? Chances are, your seedlings suffered from damping off, a fungal infection that kills seedlings before you get a chance to cure them or fix the issue. But what is damping off, what causes it, and how can you protect your cannabis plant from it? 

Read on to learn everything about cannabis damping off in this article, including its causes, symptoms, and some prevention methods that will ensure your next batch of cannabis seedlings don’t meet the same fate. 

What is Damping Off?

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Damping off is a condition that affects seedlings and young cannabis plants, and since it is fast-acting in nature, it has the potential to take your plant’s life within a few days. In some cases, damping off can even stop your cannabis from germinating in the first place. 

This condition can even transfer to other cannabis plants in the vicinity, but it doesn’t have to be. You can learn how to minimize the damage and prevent it, but before we go there, you must learn what is damping off in the first place. 

Damping off is a class of fungal infections that cannabis plants suffer from in the seedling stage. It is called damping off because, as you can guess, the plant starts looking soggy and damp. It then starts wilting and becoming limp, and eventually collapses and dies. 

This condition is a result of a few microbial species that start attacking the cannabis plant’s roots when they are still young. As you can guess, this condition is nasty for cannabis — the seedling stage is where nutrients are crucial for giving your plant a head start in life. 

As a result, if your cannabis seedling is suffering from damping off, there’s not much you can do to save it. In most cases, cannabis seedlings die due to damping off. But if you take the right steps, isolate the infected plants, change your soil or growing medium, and take some preventative measures, you can still save the rest of your cannabis plants. 

If you have some experience growing cannabis, we don’t need to tell you how important it is to safeguard seedlings. They are vulnerable, like children, and need the utmost care to ensure that they grow healthy. Most importantly, the early stages of a plant's life are incredibly significant for its well-being, productivity, and ability to withstand challenges. 

This is why you shouldn’t feed nutrients when the plant is still in its early stages. A small mistake can ruin everything as the plant is still establishing a strong root system that will later help the plant in various stages of growth. 

Apart from that, you should protect the seedlings if you look at it from a financial perspective. You spend so much on seeds, soil, water, nutrients, and your time to ensure you get good yields, which is why it can feel like it’s the end of the world when a seedling just dies without any apparent reason. 

Which Microbes Cause Damping Off in Cannabis?

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As mentioned earlier, damping off is caused by some microbial life that lives within the soil or the rhizosphere. These include the following. 

1. Botrytis

Botrytis is also known as bud rot or gray mold, and this is a type of fungus that generally develops on the buds. As a fungus that thrives in high humidity, especially in outdoor gardens with a lot of rain, it can also do well if you’ve maintained poor sanitary conditions. 

Typically, botrytis spores reach the buds and stay dormant until the environment is humid for them to grow. Once the conditions are right for this fungus, it starts multiplying rapidly and within a couple of days, it can completely take over the bud and rot it from within. 

One of the symptoms of botrytis is damping off, which can kill your cannabis plants quickly. Other symptoms include yellowing leaves and colas, shriveling leaves, discolored or limp buds, gray fuzzy specs on the buds, crumbling or dry leaves and buds, etc. On a side note, look out for caterpillars in your cannabis garden. Their droppings tend to cause botrytis onset on plants. 

2. Fusarium 

Fusarium is another type of common fungus that belongs to the filamentous genus, and most of the fusarium species are categorized as saprophytes — they feast on organic matter in the rhizosphere. 

Some Fusarium species can also be parasitic, and they can prey on host plants, leading to a condition called fusariosis. Eventually, this condition can kill your cannabis plant. 

Fusarium is such a nuisance that it is classified as a pathogen to crops globally. This fungus can live dormant in the soil for years, but when the conditions are right, it starts taking over your plant. 

Sometimes, if your seedlings are unlucky, fusarium can prey on them too. Here, they clog up your plant’s xylem, starving them of nutrients and water. Eventually, it kills the seedlings. 

3. Rhizoctonia 

Rhizoctonia solani is a type of fungal species that stays dormant in the soil for many years, but it can get activated due to warm conditions or plant debris. When this happens, it can start taking over your cannabis plant and causing damping-off in it. 

What makes this problem such a nuisance is that it is very difficult to spot in the beginning as it develops as brown root rot under the soil. Then, the stem starts turning red/brown at the bottom as the fungi spread further, and what comes next is discoloration in the leaves and buds. Eventually, death takes the seedling. 

4. Pythium 

Pythium is a notorious fungal species from the Oomycetes group, and this species is known for attacking cannabis plants regardless of their age; young or old, pythium can wreak havoc for your cannabis plants. 

Pythium infection starts with a curling and yellowing of leaves and wilting edges. Over time, this translates to damping off. One of the signature symptoms of pythium is the formation of lesions at the seedling’s base that gradually move upwards. 

5. Phytophthora

Phytophthora is a type of fungus that contains over 80 species, and this is also known for causing damping-off in cannabis seedlings. Like most fungal species, phytophthora is also found in wet conditions, especially compacted or clay-rich soils. 

Common symptoms of this fungal infection include rotting tissue of the plant, poor plant health, and blight. And of course, it can cause damping off in seedlings, eventually killing them. 

These aren’t the only fungal species that cause damping off in cannabis plants. There are some morFungingi thrive in humid environments, so if you don’t fine-tune your grow room’s temperature and humidity properly, disaster is waiting to happen. 

How to Spot Damping Off in Cannabis?

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Now you know the common microbial species that can cause damping off in your cannabis plant, but how do you spot damping off? It’s fairly straightforward in most cases, so a keen eye and some patience should help you identify damping off soon enough. 

Typically, the symptoms of damping off are akin to overwatering symptoms. Why? When you overwater your cannabis plant, excess moisture within the rhizosphere leads to root rot, which is another type of fungal infection. It’s the perfect environment for fungi to thrive. 

When your cannabis plant is suffering from either root rot from overwatering or from damping off, the roots fail to absorb nutrients from the soil efficiently. 

Unfortunately, it’s rather challenging to spot damping off before the problem has gotten too serious; beyond this, the only thing you can do is cut your losses and protect the rest of your plants. 

When you do realize your cannabis plant is suffering from damping off, it is already too late for your plant. These fungal species attack the plant under the soil, not above it, so you don’t notice it until they’ve done enough damage to produce symptoms on the plant. 

In fact, damping off can potentially kill cannabis seedlings within a day before you even realize what has happened. 

Nonetheless, you should keep a look out for the first visible sign of damping off, which is that the plant’s stem will start rotting. This rotting typically begins at the base and gradually moves upwards on the stem. 

The second symptom you’ll generally notice when your cannabis seedling is damping off is discoloration of the foliage. It will start turning from lush green to red or brown. 

Sometimes, the stem may also develop white spots at the base, and the branches will start looking thin and dark. The stem can also look dehydrated in color — this is a sign that your cannabis seedling is a few hours away from its last breath.

Other symptoms of damping off include the plant appearing soaked or wilting, discolored stem, collapsed seedling, rotten roots, mold on soil, etc. Eventually, the seedling will bend at the weakest point in the stem and will die. 

What Causes Damping Off in Cannabis?

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Pathogens like various fungal species cause damping off in cannabis plants, but that’s only one side of the story. These pathogens don’t attack cannabis plants on a whim or randomly; they need to be brought in and provided with the right kind of environment for them to thrive. 

Ultimately, this is what causes damping off in cannabis. While these fungal species are responsible, they aren’t the root cause of the problem. That credit goes to various environmental factors leading out of grower error or lack of experience.

Here are some reasons why these fungal species can cause damping in your cannabis plant. 

1. Overwatering 

One of the leading causes of damping off in cannabis plants is overwatering, and this problem can lead to many other problems. In many ways, overwatering is perhaps the worst innocent mistake new growers tend to make while growing cannabis. Sometimes, more isn’t better. 

When you overwater your cannabis plant, you load the soil with too much moisture and lack of air — the perfect conditions for a fungal infestation. Yes, the seeds require damp soil or rhizosphere to germinate properly, but too much water can be counterproductive in nature. 

Overwater soil gets waterlogged, which can also lead to many other problems for your cannabis plant, including nutrient lockout, nutrient toxicity, starvation, suffocation, root rot, slimy roots, and much more. This is why you must never overwater your cannabis plant. 

2. Poor Soil Drainage 

Let’s say you water your plant just the right amount and when required, never too much. You water your plant by the book, but if you have the wrong kind of soil, following the book doesn’t help much. 

If your cannabis soil has poor drainage, it recreates the same effects of overwatering since the water cannot escape the soil efficiently. You may face this problem if your cannabis soil is rich in clay, compacted too much, or your container does not have any runoff drain holes. 

3. High Humidity

Similar to overwatering, if your grow room is too humid, you are inviting fungi to your garden in many ways, one of which is damping off. This is a tricky problem since seedlings do require high humidity to germinate well, so you need to strike the right balance. 

Strike the wrong balance by keeping the humidity too high and fungal spores will thrive in the soil and before you know it, your plant will be damping off. It is wise to always keep an eye on the humidity levels, err on the side of caution, and use humidity levels as per your plant’s growth stage. 

4. Cool Soil 

One seemingly unlikely but totally plausible cause of damping-off in cannabis plants is soil that is too cold. Like high humidity, low temperatures are also ideal breeding grounds for fungal species to thrive. No wonder the high heat of the sun sometimes disinfects soil, isn’t it? 

So, this is where it becomes crucial that you keep your cannabis soil’s temperature at the right levels, based on your plant’s growth stages. 

5. Infected Compost

Many growers use compost to grow cannabis, and if you are not doing so already, you should consider this method. Compost is one of the best organic supplements for your cannabis plants. 

But sometimes, luck may not be on your side. In such cases, if you end up using compost that is already infected with fungal spores, you are only bringing them to your garden and giving them everything they need to multiply within days. 

How do you avoid this? Always purchase high-quality compost and potting soil that is disinfected and treated properly. This is a small thing that can lead to major problems if you are not careful enough. 

6. Infected Seeds

Like accidentally purchasing infected compost, you can also purchase infected seeds if you tend to purchase seeds on a whim and without enough due diligence. So, always prefer to purchase high-quality seeds from reputable seed banks that provide third-party lab test results and more. 

7. Too Many Seedlings 

We’re not saying don’t grow too many seedlings. If you can, grow a thousand cannabis plants — the more the merrier — but be careful about how to space them in your grow room. 

If your cannabis plants or seedlings are placed too close to each other, they are prone to fungal infections like damping off. This is because crowding reduces the flow of air and even increases their ambient humidity. 

Can You Treat Cannabis Damping Off in Cannabis?

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Unlike many other cannabis problems, damping off gets the shorter end of the stick — in most cases, you cannot treat it or reverse it. Nonetheless, not all hope is lost because some fungal infections can be reversed. 

If you suspect your cannabis seedling is close to damping off, you need to act quickly. You may only have one day to save it before it tips over and dies. First, try and support the seedling using a string, stick, or anything else that can hold the weight of the seedling and prevent it from falling off. 

Next, use a broad-spectrum commercial fungicide as you need it to act quickly. Other options include using hydrogen peroxide solution, neem oil, or any product containing peroxyacetic acid. You can also use a solution that contains garlic, lemon juice, canola oil, and hot peppers, which have antifungal properties; however, be aware that these solutions don’t work fast. 

Use your choice of fungicide as a foliar spray and spray down your cannabis seedling from top to bottom. 

But in most cases, you won’t be able to save your cannabis seedlings. In any case, you should isolate your infected seedlings from the rest so the fungal infestation does not spread to other plants in your garden. 

In the worst-case scenario, it is always recommended to cut your losses and fix the problems that may have caused damping off in the first place. It’s better to lose a seedling than lose them all while trying to save one. 

You should also discard your infected compost or potting mix. Fungal spores are ancient organisms that have survived through several world-ending events, and they can survive a lot more than you can imagine. They can stay dormant in your soil for years before they wake up and start multiplying. 

How to Prevent Cannabis Damping Off?

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Curing damping off may not be possible all the time, but you can always take some measures to prevent it from occurring in the first place. Here are some techniques you can use to prevent cannabis from damping off. 

1. Timing of Planting

Understanding when to plant is crucial for cannabis cultivation. You should consider the growth phases particularly focusing on germination and transplanting while being mindful of environmental conditions whether you're growing outdoors or indoors.

First, make sure the seeds germinate properly. Germination marks the beginning of the cannabis growth cycle. To promote seedling development, you should provide optimal conditions so the seeds germinate without issues. Seeds prefer a moist environment, with temperatures typically between 70 to 85°F (21 to 29°C). 

You should also maintain humidity levels during germination as it increases the chances of successful seed germination. In addition, proper moisture levels are important for the seed coat to break and encourage the healthy growth of a taproot.

Once the seeds have germinated, the next step is to transplant them properly. Of course, you should wait until the seedling develops a few leaves and has a healthy root system to reduce stress or transplant shock. If you do it at the wrong time, it makes the seedling less susceptible to damping off pathogens. 

If you live in cold regions, you should manage frost as well. Don't plant cannabis seedlings early in the season when frost is still possible. Wait until the soil has warmed up enough to provide an environment for seedling growth.

2. Choose the Right Container

Choosing the container is vital for transplanting. Make sure the containers have proper drainage and enough space for roots to grow.  It doesn’t have to expel all the water as soon as you water it, but it should not retain too much water, either. This allows for nutrient absorption and also prevents waterlogging, which can lead to damping off.

3. Proper Lighting

Adequate lighting is crucial for seedlings. However, you should choose lights that don’t burn the tender seedlings in the process. Many growers use CFLs specifically for this purpose. But, if you have LEDs that are meant to support the plants during their entire life span, you can use them. Just make sure you hang the lights at the right distance. 

4. Use Clean Equipment 

In your garden, you should always use clean equipment, whether it is trays, containers and pots, pruning scissors, humidity domes, etc. And it is also a good idea to disinfect your gardening tools and grow room regularly. 

Fungal spores can hitch a ride on unsanitary equipment and make their way into your cannabis soil. So, it is of utmost importance that whatever you use in your grow room is clean and disinfected. 

5. Don’t Overwater Your Plant 

More water seems better, but it is not. Only water your cannabis plant when needed and the right quantity. Overwatering is never a good idea. 

So, if you are growing a seedling, ensure the soil is damp but not pooling water. For the rest of your plant’s growth cycle, only water the plant when the top inch of the soil is dry, and water it until 25% of the water runs off from the drain holes. 

6. Keep Humidity Levels in Check 

When growing cannabis, never underestimate the power of ideal humidity levels. You should aim for a humidity of around 65% to 70% for seedlings especially since damping off usually occurs in cannabis seedlings. 

7. Use Beneficial Microbes

One effective way of preventing harmful pathogens from thriving in your cannabis soil is to load it up with their predators, such as the following. 

• Lactic Acid Bacteria 

Lactic acid bacteria can be added to cannabis soil and other growing mediums to prevent damping off. Do note that this is an overkill for hobby growers, but it’s an excellent solution if you are growing many cannabis seedlings. 

• Mycorrhizal Fungi 

Mycorrhizal fungi develop a symbiotic relationship with cannabis plants, so they work together. This fungi helps fix various nutrients for the cannabis plant and the roots help sustain their population. 

Fortunately, mycorrhizal fungi do not let other pathogens thrive in the soil, protecting your seedlings from damping off. So, these fungi not only help improve your soil’s health but also keep it safe from harmful pathogens and even some insects. 

• Trichoderma 

Another beneficial fungus that you can use in your cannabis garden is Trichoderma, which also helps protect your cannabis seedlings against harmful pathogens that can cause damping off and other problems. 

This fungi works in a similar fashion to mycorrhizal fungi — symbiotic relationship and nutrient fixing — thereby protecting your cannabis plant from damping off. 

Differentiating Damping Off from Cannabis Issues

Cannabis, like most plants, can encounter problems from various pests and deficiencies. However, to treat the problem, you should be able to distinguish one issue from another for best results. For example, the leaves could turn brown, making you assume it’s some deficiency; however, it could just be a pH imbalance. Once you identify the problem, you should monitor the plants regularly and treat them immediately to reduce the damage. 

So, here are a few tips to help you recognize and differentiate damping off from other problems:

1. Damping Off vs Overwatering

Damping off occurs when soil-borne fungi like Pythium or Rhizoctonia cause the seedlings to collapse. The lower part of the stem close to the soil seems to be soaked with water and might show mold.

On the other hand, cannabis plants that have been overwatered exhibit signs such as drooping leaves, yellowing, and potential root problems. These symptoms develop gradually, compared to the fast death of seedlings in damping off. This is because excessive watering doesn’t allow the soil to drain properly, reduces oxygen supply, and also affects the roots.

2. Damping Off vs. Underwatering

Damping off causes the stems to become weak. As mentioned earlier, they look like they are soaked with water. The leaves begin to wilt with signs of decay at the base. Eventually, the plant collapses.

If the plant suffers from underwatering, whether it’s because you forgot to water it or couldn't do it for some reason, the leaves begin to wilt too. Insufficient watering results in dehydration stress for the plant and issues with absorption. However, the difference is that the leaves also become dry and crispy. Unlike damping off, these symptoms typically start from the top of the plant and progress slowly.

3. Damping Off vs. Nutrient Deficiency:

As you already know by now, damping off mainly affects the stem, and is confirmed by rapid wilting and decay. You might notice a presence of mold or fungal growth, near the soil line as fungal diseases could simply make the problem worse. 

Conversely, nutrient deficiencies in seedlings are rare as the cotyledon has enough energy to sustain the growth until it grows at least 2-3 nodes. So, you don’t have to feed nutrients to the seedlings. However, some seedlings may still display yellow leaves, which could be a sign of a nutrient deficiency. But, before checking for deficiencies, you should assess whether the pH is in the acceptable range. In addition, check whether the growing medium is too moist as the culprit could be excessive watering too. 

4. Damping Off vs. Pests

Damping off primarily affects the stem of plants, and the damage isn’t as visible as pest damage. Although soil-borne fungal pathogens are responsible for damping off, they aren’t directly associated with pests.

Pest-related damage includes chewed leaves, visible presence of pests on the plant, or stippling marks. 

Summary: How to Protect Your Seedlings From Damping Off?

Cannabis damping is a serious concern that can kill your seedlings quickly. This problem is caused by various fungi species, including Botrytis, furasium, Rhizoctonia, and Pythium. When this occurs, it hinders the seedlings’ ability to absorb nutrients, eventually causing their death. 

This problem is a result of errors like overwatering, poor soil drainage, high humidity, infected seeds or compost, etc. Unfortunately, it’s not an easy problem to cure or reverse. 

Fortunately, it is easy to prevent in the first place by maintaining hygiene in your cannabis garden, watering your plant properly, and keeping humidity levels in check. Follow these steps and you won’t have to worry about your cannabis plant damping off.