How to Fix and Prevent Nutrient Lockout in Cannabis Plants?

How to Fix and Prevent Nutrient Lockout in Cannabis Plants?

There’s a plate full of food right in front of you, but your hands are tied and you can’t eat. Imagine if this happened to you; you have food to eat but an inability to actually eat it. Sounds terrible, doesn’t it? 

That’s exactly what your plant might feel if it had feelings when suffering from a nutrient lockout. There are nutrients in the soil but it just can’t absorb them properly. But what exactly is nutrient lockout and how do you fix it? 

In this article, we go over the definition and symptoms of nutrient lockout, its common causes, and various ways of fixing and preventing it. Read on to know everything you need to know about nutrient lockout in cannabis plants.

What Exactly is Nutrient Lockout?

As a cannabis grower, it’s no surprise that you’ll be facing many problems when growing cannabis, especially if you are a beginner. This is part of the process. And one such problem that’s often more common than the rest is nutrient lockout. 

The problem can be quite annoying to deal with, especially for new growers, since it can be a bit tricky to figure out correctly. And it’s easy to confuse this problem with others, like nutrient deficiency, nutrient toxicity, or bad soil. 

So, what exactly is nutrient lockout in cannabis plants? Essentially, this problem occurs when your plant fails to absorb the nutrients from the growing medium, regardless of how much nutrients you feed it. As the name suggests, during this problem, the nutrients are locked out of the plant. 

Generally, nutrient lockout occurs due to various chemical reactions within the rhizosphere between water/nutrient solution, roots, microbes, and the growing medium itself. And the results can be quite devastating for your plant if you don’t deal with them properly. 

Primary Cause of Nutrient Lockout: Too Much Nutrients 

What causes nutrient lockout? It can be many things, but more often than not, it is caused due to excess nutrients being fed to the plant. Your cannabis plant thrives by absorbing the nutrients and water from the soil, but sometimes, excess nutrients can create problems.

When you feed your plant a lot of nutrients, the growing medium can start accumulating the nutrients and salts. Once salt buildup exceeds a certain level, it can stop other nutrients from being absorbed into the soil. 

What happens is that all the built-up salts and nutrients start reacting with the nutrient solution and the roots; they can either bond or turn incompatible, both of which cause problems for the roots. And, they get locked out. 

Second Common Cause: Improper pH

Another common reason for cannabis plants experiencing nutrient lockout is due to improper pH levels. Your cannabis plant needs a pH of around 5.5 to 6.5 in hydroponic systems and 6 to 7 in soil. This is the range where the roots can efficiently absorb all the nutrients from the growing medium or soil. 

But sometimes, the pH can stray outside the optimal range, and when this happens, your plant fails to absorb some or all nutrients. This is because nutrients are only available to the plant within a specific pH range. 

For example, manganese and iron can still be absorbed at pH 5, but magnesium and calcium become unavailable. This can lead to the plant suffering from cal-mag deficiency due to the nutrients being locked out. 

Other Causes of Nutrient Lockout in Cannabis 

Apart from excess nutrients and incorrect pH, sometimes, nutrient lockout can also be caused due to other reasons. Here are some other common causes of nutrient lockout in cannabis. 

• Quality of the Water

One of the surprising causes of nutrient lockout in cannabis plants is the quality of water, i.e., low-quality water. Remember, water is the main way your plant’s roots absorb nutrients, so if it is not proper, the roots may fail to absorb the nutrients properly. 

Generally, this occurs when your water is too hard. What is hard water? Hard water contains lots of minerals and also has calcium and magnesium. While your plant needs cal-mag for its health, too much can compete with other nutrients, causing a nutrient lockout. 

If you use a hydroponic system, you should be all the more careful about using hard water. This type of water can even cause scaling in hydroponic plumbing, according to the US Geological Survey. 

One more reason why you should be wary of water quality is because hard water isn’t good for the microbial health in the rhizosphere. All the excess minerals can disrupt the delicate ecosystem within the soil, which can reduce the amount of nutrients these beneficial microbes fix, leading to a nutrient lockout. 

• Health of the Roots 

Your cannabis plant may suffer from nutrient lockout due to the health of the root as well. Remember, roots are pillars of your cannabis plant; without healthy roots, your plant cannot absorb nutrients properly and it can even tip over under its own weight if the roots are weak. 

So, if your cannabis plant suffers from root diseases, like slimy roots, the roots can stop absorbing nutrients properly. When this happens, your plant starts suffering from nutrient lockout, even if the soil is packed with nutrients. 

• Environment

Lastly, even an unhealthy environment can cause your cannabis plants to suffer from nutrient lockout. If your plant’s environment is not properly dialed in, it can induce stress on your cannabis plant, which can hamper its metabolic processes like nutrient absorption. 

When this happens, your plant may fail to absorb the nutrients from the growing medium. This is supported by a study from Front Plant Sci, which states that environmental factors have a significant influence on the plant’s ability to take nutrients. 

• Beneficial Microbes

Beneficial microbes are a terrific help for cannabis plants, but sometimes, they can backfire. These microbes fix nutrients for the plant in the soil by decomposing organic materials, making the nutrients easily accessible for the cannabis plant. 

But for the best results, these microbes need to be in equilibrium. If you use chemical fertilizers or insecticides, the equilibrium can be disturbed significantly, which can not only disrupt the nutrient cycle but also cause various diseases, according to a study in Microorganisms. 

So, if you are growing cannabis in soil and using beneficial microbes to fix nutrients for your cannabis plant, you need to keep such risks in mind and encourage healthy microbial activity within the soil. 

• Nutrients Competing With Each Other 

Another factor that can cause a nutrient lockout in cannabis plants is if one nutrient starts competing or interfering with another nutrient. This is known as nutrient antagonism, where an excess of one nutrient can prevent another nutrient from being absorbed properly in the soil. 

• Soil Composition and Structure

If you’re growing outdoors in soil, the composition and structure of the soil also determine the availability of nutrients to cannabis plants. Different types of soil have their own characteristics that affect their ability to retain and release nutrients. 

For example, clay soils retain nutrients but don’t drain water quickly. On the other hand, sandy soils, drain water too quickly as they have larger particles. Thus, it’s important to strike the right balance when you’re growing cannabis plants in soil. 

Excessive use of fertilizers over time can also affect the pH of the soil. Therefore, you have to improve the soil structure by adding organic matter that’s rich in microbial matter. Organic matter derived from compost, manure, or other natural sources enhances soil fertility while also helping with water retention.

Last but not least, make sure the ground you’re planting in has rich, porous soil as compacted soils can reduce the space between soil particles, thereby limiting the movement of air, water, and nutrients. This restriction hinders the ability of the plant's root system to access nutrients, which in turn leads to a nutrient lockout. If you’re frequently experiencing such issues, you should till the soil and also add some organic matter into the soil to prevent compaction issues.

If you’ve taken all the steps and still experience nutrient lockouts, you should get your soil tested. It might help get some data on the pH, nutrient concentrations, and potential imbalances so you can understand what you should add or stop adding to help your plants grow healthy. 

What are the Symptoms of Cannabis Nutrient Lockout?

Nutrient lockout may be caused due to seemingly trivial things, although they’re not always trivial, like wrong pH or hard water, but it can be quite tricky to identify. As mentioned earlier, it is easy to confuse nutrient lockout with other conditions like nutrient deficiency. 

So, how do you narrow down the symptoms and know for sure if your cannabis plant is experiencing a nutrient lockout? We’ve got your back. Here are some of the signs you need to look out for. 

• Slow or Stunted Plant Growth 

One of the first signs or symptoms of nutrient lockout is your plant’s loss of vigor or slow growth. This is because your plant needs various nutrients to thrive, and when it plant does not get these nutrients due to its inability to intake them, it may start slowing down. 

• Leaves Turning Yellow or Discoloration

Another sign that your cannabis plant may be suffering from a nutrient lockout is if the leaves have started to turn yellow or are losing color. Leaves turning yellow is known as chlorosis and is one of the major symptoms of a nutrient lockout. 

However, this chlorosis should first start appearing in lower leaves first and move upwards through the canopy. This is because the plant will not have enough nutrients, especially nitrogen, to support the new growth. 

On the other hand, your cannabis leaves may even turn some other color, i.e., discoloration. When this happens, you may notice colors like red, brown, or purple. 

• Burnt Leaf Tips 

You should also look at the tips of the leaves to see if they show signs of burning. This can be a reliable cosmetic symptom of nutrient lockout, and usually, this occurs due to your plant being unable to uptake nitrogen. 

• Curling of the Leaves

The shape of the leaves is always a good indicator of your plant’s health. If the leaves seem curled up, it may be a sign that your cannabis plant is not getting enough nutrients, especially nitrogen and phosphorus. 

Phosphorus is one of the three macronutrients your plant needs, which is responsible for the leaves’ structure and photosynthesis, and so is nitrogen. So if your plant does not get enough of these nutrients, the leaves may start curling. 

• pH Imbalance 

The symptoms listed above can still be confused with some other conditions. So, how do you know for sure? Check the pH of the soil. By doing so, you can see if the pH is out of the ideal range. 

If it is, your plant is experiencing lockout since it cannot intake nutrients from the growing medium properly. Remember, higher pH stops the plant from absorbing micronutrients whereas lower pH interrupts the intake of both micronutrients and macronutrients. 

This is also how you can differentiate nutrient lockout from nutrient deficiency. Both issues are easy to confuse because they are essentially the same, but nutrient deficiency is when there is a lack of nutrients in the soil entirely. On the other hand, nutrient lockout occurs mostly due to the wrong pH that stops the nutrients from being accessed by the plant, leading to nutrient deficiency-like symptoms. 

How to Treat Nutrient Lockout in Cannabis Plants?

Once you know how to identify nutrient lockout in cannabis plants, the next step is to start fixing it. You don’t need to wait too long here as it can significantly affect your plant’s health and yield. So, the moment you notice a nutrient lockout, it’s time to start working. 

Here are some ways you can fix nutrient lockout in cannabis plants. 

• Fix the pH 

As mentioned above, nutrient lockout is usually tied to incorrect pH levels in the soil. So, one of the first things you should do is fix the pH of the soil and make sure it is within the ideal range. 

So, how do you check and fix the pH? First, test the pH of the water before feeding. Then, check the pH of the water running off from the container. Both the readings should be within the ideal range of 5.5 or 6.5 in hydroponic systems and 6 to 7 in soil. 

Although you can use vinegar or lemon to decrease the pH and baking soda to increase it, they aren’t recommended. Instead, use pH Up/Down solutions for precision. They are available in most nursery stores and online too, so finding them shouldn’t be a problem. 

Follow the steps mentioned above, especially checking and fixing the pH if it is out of the ideal range. In soil, you can also add wood ash or dolomite lime to raise the pH and sulfur to reduce the pH. 

You can also use various soil amendments that can help manage the pH of the soil in the long run. Here, you can use manure, compost, and alfalfa to reduce the pH and crushed egg shells or oyster shells to increase the pH. We will discuss this below. 

• Flush the Soil 

Sometimes, nutrient lockout can also be caused due to excess salt buildup within the soil. So, you need to test the pH of the soil by comparing the readings of the nutrient solution and runoff water. If the runoff pH is too different from the solution, your soil or growing medium has salt buildup. 

In such a case, you need to flush the soil. These nutrients are water soluble, so use enough water and they will be washed out of the medium. You can do this by running a lot of water through the soil for some time. It's essentially like washing the soil and roots. 

• Foliar Feed Your Cannabis Plant

When your cannabis plant is suffering from a nutrient lockout, it is not getting enough nutrients to keep its vigor. Fixing the issue may take a few days, but this can still damage your cannabis plant. 

Fortunately, your plant can intake nutrients from the leaves, too, via small pores called stomata. So, you can start foliar feeding your cannabis plants while the problem gets fixed within the root zone; this will minimize the damage of nutrient lockout to a great extent. 

• Use Chelated Nutrients 

Chelated nutrients are excellent supplements for your cannabis plants and they offer tremendous benefits over the usual mineral salt nutrients. So what are chelated nutrients? 

In simple words, these nutrients are designed to be easily absorbed by the cannabis plant. As a result, they are less prone to nutrient lockout and can go a long way in fixing the issue for your plant. 

At the same time, you should also use microbial inoculants. These help boost nutrient cycling in the growing medium, making the nutrients easily available to your plants over a long time instead of fixing them instantly. This reduces the risk of salt buildup, which is common with synthetic nutrient solutions. This can best be achieved with trichoderma, mycorrhizal fungi, and lactic acid bacteria. 

• Fix Your Feeding Cycle 

If your cannabis plant has excess salt buildup within the soil, it is likely due to you feeding too many nutrients to your cannabis plant. In that case, you need to rework your feeding cycle and nutrient solution — dial back a bit — so that your plant does not experience the same problem again. 

Organic Amendments to Increase or Decrease pH in Soil

• Dolomite Lime to Increase pH

Organic amendments such as lime is best to increase the soil pH gradually. Agricultural lime typically contains either calcium carbonate or calcium magnesium carbonate. When you add it to the soil, it reacts with the acidity. 

Not only does it increase the pH level, but it also improves soil structure and enhances nutrient availability gradually. To apply it, you can either mix it while preparing the soil or use it as a dressing. Just make sure you follow recommended guidelines and regularly monitor pH levels to avoid overcorrecting.

• Using Sulfur to Reduce pH 

Sulfur provides a solution for lowering pH in soil. If you’re looking for eco-friendly alternatives to chemical-based pH solutions, sulfur can help. When you apply sulfur to the soil, it reduces the pH by acidifying alkaline soils. As sulfur undergoes conversion into sulfuric acid, it gradually lowers the pH level. 

This makes it a reliable and environmentally friendly option for correcting alkaline soil. In addition, as it happens slowly, it prevents sudden pH fluctuations, thereby reducing the shock your plants may otherwise experience if there are sudden drastic changes in the pH. 

You can use either elemental sulfur or sulfur-containing compounds. The amount of sulfur to apply depends on the pH and the desired adjustment. As always, follow recommended guidelines and consistently monitor pH levels to prevent the soil from becoming too acidic. 

Buffering Agents for pH Stability

Dolomite lime consists of both calcium and magnesium carbonates so you’re also adding magnesium and calcium which are both very important for cannabis. When you add dolomite lime to your soil, it serves as a buffer to regulate the pH and prevent sudden fluctuations.

You have two options for using dolomite lime: either mix it into the soil while you’re preparing it or apply it as needed throughout the growing season. The buffering effect of dolomite lime helps maintain a stable pH and reduces stress on cannabis plants. It's important to monitor pH levels so you can make adjustments immediately if necessary. 

Considerations for Hydroponic Systems

Even though hydroponic systems offer more control, they can be unforgiving in some ways. To adjust the pH and keep it between 5.5 to 6.5, it’s best to go for pH Up and pH Down. You’ll also need to check the pH frequently as plants in hydroponic systems cannot handle too many fluctuations. 

Remember to clean and maintain the system regularly to prevent clogs, blockages, or any buildup that could impede the flow. Make sure to inspect and clean components like pumps, hoses, and irrigation lines to ensure that the nutrient solution can flow smoothly without any obstructions. The presence of salts or debris in the system can lead to lockout.

You should also check for mineral buildup in your setup that’s often visible as white deposits as they can interfere with the nutrients and cause a lockout. 

Will My Cannabis Plant Recover From Nutrient Lockout?

The biggest question when dealing with a nutrient lockout in cannabis plants is if your plant will even recover from it. Fortunately, yes. Unlike other serious problems that may not be reversed, nutrient lockout is fairly easy to fix and your plant will indeed recover. 

Follow the steps mentioned above and you’ll start noticing the difference in a matter of days. But how long does it exactly take for a full recovery? That varies from plant to plant and on other factors. 

If you identify the symptoms early and take the right measures to fix the issue, it won’t take long. But even if you catch the problem late but take the right approach to fix it, your plant will be back to normal within a few days or even a couple of weeks. 

How to Prevent Nutrient Lockout in Cannabis?

Nutrient lockout can really hamper your plant’s performance, so you must prevent it instead of fixing it when it happens. As the old adage goes, prevention is always better than cure, isn’t it? 

Here are some steps for preventing nutrient lockout in cannabis plants. 

• Regularly Check the pH

Invest in a good pH pen and make it a habit to check the pH of the nutrient solution and the soil regularly. We’re talking on a weekly basis or even more frequently if you have the time. This will help you spot pH fluctuations before they become a problem for your plant. 

• Use Organic, High-Quality Nutrients

You get what you pay for, when it comes to nutrients. So, don’t try to save a few pennies here and get the best YOUR money can buy. Invest in high-quality nutrients from reputable manufacturers. You can use organic fertilizers that release nutrients slowly or whatever you prefer. However, make sure you purchase them from a reputed brand. 

• Get Living Soil 

If you are using soil to grow cannabis plants, try and get living soil for the plant. Such soil contains a rich microbial life that will fix the nutrients for your cannabis plant, making them readily available for your plant. Or, make your own super soil at home and watch your plants grow like crazy. 

• Be Consistent 

Just because your plant can take a lot of abuse, does not mean it should. So, don’t take your plant for granted, and be consistent with your schedule. Maintain a journal or diary and feed your cannabis plant on time. This will prevent you from giving your plant too much nutrients, which may cause nutrient lockout. 

• Stay Vigilant

You should also be vigilant and check your plant for any signs or symptoms of nutrient lockout or other problems regularly. It takes a few minutes of your day but it is so worth it since it lets you find problems much earlier and you can fix them before they get too severe. 

Summary: How to Fix and Prevent Nutrient Lockout in Cannabis Plants?

Nutrient lockout occurs when your cannabis plant fails to absorb the nutrients from the growing medium or soil. This usually happens due to incorrect pH levels or excess salt buildup within the soil, but it can also occur due to other reasons like improper environment or hard water. 

In any case, it is marked by symptoms like stunted growth, yellowing, discoloration or curling leaves, and pH imbalance. When this happens, you need to fix it by flushing the soil, fixing the pH, and foliar feeding your plant in the meantime. You can also use other methods like chelated nutrients to hasten the process. 

In any case, remember to check the pH of your soil regularly, use organic and high-quality nutrients, and be consistent and vigilant with your feeding cycle. Follow these steps and you will never have to worry about nutrient lockout ever again. 

It’s a serious problem that can be a bit confusing to figure out, but fixing it is much easier than the emotional stress of losing a plant by caring for it too much, isn’t it?