What is Nutrient Lockout?

Nutrient lockout is a term for when plants are unable to take in necessary nutrients in their medium, whether that be soil, coir mix, or even hydroponic solution. It is caused by a chemical reaction between the nutrients, growing medium, and plants that stops the plants from absorbing what they need to grow and survive. It’s not the same as nutrient burn, although they have slightly similar causes.

Plants are living things just like animals, and as such, they produce waste products when they absorb and process nutrients. However, what many growers do not realize is that plants release more than carbon dioxide from the oxygen they consume. They can also accumulate excess substances from the nutrients they get, such as excess salts or other pH-altering substances.

If these waste substances develop too far, they can bond with the nutrients in the medium in a way that makes them incompatible for plants to consume them. Usually, this means that the waste nutrient products have altered the growing medium’s pH level and stopped the plants from effectively feeding and growing.

What Does Nutrient Lockout in Plants Look Like?

Nutrient lockout causes plants to not receive the nutrients they need, even when the nutrients exist in proper levels in their medium. As a result, the signs of this problem are all the same as those of insufficient fertilizing:

• Stunted growth.
• Yellowing or browning leaf edges.
• Limp, weak leaves and/or stems.

If you see these problems even while providing your plants with the right levels of fertilizer and nutrients, then you most likely have a nutrient lockout issue. Make sure that you are giving your plants the right amounts, however, because misdiagnosing nutrient lockout can cause further problems.

Nutrient Lockout vs. Nutrient Burn

Misdiagnosing nutrient lockout for nutrient burn, or vice versa, can ruin a novice gardener’s plants, so it’s vital to understand the difference between the two.

In brief, nutrient burn is the opposite of nutrient lockout and happens when a plant absorbs too many nutrients — in essence, overfertilizing. It causes a similar yellowing of leaves but no weakness or limping. Nutrient burned plants also have darker green leaves than usual, more and more of which start to “burn” yellow or brown at the leaf tips and curl inward.

If you aren’t familiar with nutrient lockout and burn, it could cause a dangerous chain reaction. For instance, suppose a grower has a nutrient lockout problem but has never heard of it. They see their plants behaving like they aren’t getting enough nutrients, so they add an excessive amount of additional fertilizer to try and fix the problem.

If they are able to address the lockout problem later on, then the excess nitrogen or other elements from the unnecessary fertilizer could cause nutrient burn and further harm the plants. Alternatively, if the gardener doesn’t fix the lockout but still adds more nutrients, the pH will only be further thrown off balance.

How To Fix Nutrient Lockout in Soil

The only way to fix nutrient lockout is with a flush. In hydroponics, this only requires replacing the solution with clean, pH-balanced water and adding in the proper amount of fertilizer. With soil, the process is also fairly simple. Just run water through the pots or along the ground. Be aware that flushing can overwater roots in soil or soil-like mediums. To avoid this, do one steady flush, and then stop and wait for the medium to dry up a little before fertilizing and watering gradually over the next few days.

Depending on the setup you use, whether soil in planters, a garden with manure and soil, or even hydroponic growing with coco coir  you will need to adjust your flushing amount and methods. As long as you get the excess salt and minerals out without overloading the roots and then re-fertilize if needed, your plants should return to a healthy state over time.

Ultimately, like many problems growers face, prevention is more effective than a cure. With a little effort and monitoring, you won’t have to worry about your plants getting nutrient lockout.

How To Prevent Nutrient Lockout

Flushing is even less of a hassle when it becomes your way of avoiding and preventing nutrient lockout rather than a way to cure it. The best option is to check the medium’s pH levels regularly, and then do small flushes when necessary to keep it in balance. It takes no more time than checking and adjusting nutrient levels.

Some growers also choose to flush more effectively by using more than just plain water. You can find flushing formulas with a small level of fertilizer, but without knowing the elements in that fertilizer-mixed water and what nutrient level your plants currently have, this is an unreliable fix. Various companies sell flushing nutrient formulas, but ultimately, the safest option is to prevent pH imbalance before it can starve your plants.

How To Monitor pH for Plants

Monitoring pH is as simple as using pH test kits or tools on your growing medium. The ideal level varies depending on that medium and on the plant species, but for the most part, a range of 5.5 to 7.0 is safe. In cases of overly low or overly high pH levels, flushing and carefully reintroducing fertilizer will balance things back to normal.

Some growers use reverse osmosis water for flushing, which guarantees that the water is pH balanced and free of impurities, but this is only an extra measure and not mandatory. Other growers use nutrient mixes that are specially designed to maintain pH. These are usually made for hydroponic growing, but again, they aren’t a requirement to balance pH and nutrients effectively.

Nutrient lockout can be a problem that many growers face, especially beginners. However, once you know the signs and how to diagnose, prevent, and treat lockout correctly, you’ll never have to worry about it again.