Nutrient Lockout: What It Is and How To Prevent It

Among the many problems that hydroponics growers encounter, nutrient lockout is one of the most common and most troublesome, as it can affect an entire batch of crops, resulting in crop death, under-production and a host of other associated problems.

If you feel that your crops are suffering from nutrient lockout, today’s blog post can help shed light on why this occurs, and what you can do to stop it.

What Does Nutrient Lockout Mean in Hydroponics?

Nutrient lockout or “nutrient lock” occurs when crops are unable to absorb the nutrient that should be freely available in the hydroponics system.

The problem can be hard to spot for first time growers and ultimately, it can lead to the demise of a lot of crops if it is not resolved as quickly as possible.

The main problem when nutrient lock occurs is plants can remain mostly green and healthy-looking, until major symptoms are seen on the leaves and roots. By then, many of the plants will be ready to wilt and die off, en masse.

Can Too Much Nutrients Cause Nutrient Lockout?

Ironically, one of the major triggers of a nutrient lockout in hydroponics systems is having too much nutrients in the water.

The over saturation causes a chain reaction that ultimately affects the capability of the plants to absorb the nutrients.

Essentially, what happens is that the plants are starved in the system despite the overabundance of nutrients in the water.

When a lockout occurs, the grower has to take fast steps to liberate the nutrients and save his crops. Otherwise, crop die-off is a real possibility.

Does Improper pH Balance Cause Nutrient Lockout?

Improper pH can cause nutrient lockout, as well as the improper application of nutrient solution or fertilizers to the hydroponics setup.

Again, what makes this condition unique is that your plants will begin to look underfed even if you are religiously adding fertilizer to your system. This is probably the first thing you should be watching out for.

If the system is constantly being replenished with nutrients, the plants shouldn’t look underfed at all.

What Does Nutrient Lockout Look Like?

Since nutrient lockout is all about nutritional deficiency, you should watch out for the most common symptoms associated with poor nutrient uptake and utility. Among the most common signs of nutrient deficiency are:

1. Stunted growth – Smaller overall structure, small flowers, fruits, leaves are sparse instead of dense. Check the common appearance of mature plants and compare with your own to see if your crops are on the right track.

In the event of a nutrient lockout, you will see warning signs that your crops are not getting enough nutrients. Again, you need to act quickly if you want to reverse the trend, otherwise, all your crops may die off.

2. Leaves – Yellowing leaves often signal deficiency in different minerals, including magnesium. Yellowing plant matter may also signal too high levels of salts and pH level imbalances.

Some plants may also show signs of pink and yellow speckling. The leaves would be bordered by green, but there would be numerous and obvious patches of yellow and pink, especially in the region near the center of the leaves.

Additional signs of nutrient deficiency in the leaves of plants are:

– Seeming drying and browning of the edges of the leaves.

– Browning and curling.

– Foliage has a dull color mixed with some yellowing.

– The leaves may not be naturally jaunty and erect as they should. Some leaves would exhibit a paler pallor and look like they’re drying.

– In some cases, reddish-brown tinting may appear alongside a dull green pallor and some yellowing.

Take note that both too high/too low pH levels can cause nutrient lockout in hydroponics systems. Getting the pH balance right can be tricky at times because this is often plant-dependent. Some plants require more of a specific nutrient than others, and this leads to deficient absorption of other nutrients.

A good example of this would be manganese absorption. At the pH level of 5, manganese is actually better absorbed by plant roots. However, at the same pH level, calcium and magnesium are left out. As the grower, you need to find the best pH level that will not compromise your plants at all.

This can be done by closely observing the pH trend in your hydroponics system and matching the conditions of the nutrient solution with the appearance of the plants. Minute adjustments to how much fertilizer you are adding to the system on a daily basis can have great effects on the system as a whole.

How To Fix Nutrient Lockout?

Before doing anything to remedy a potential nutrient lockout, make sure that you correlate the physical appearance of your plants and the tests you have been doing of the nutrient solution.

There has to be a strong correlation before you can make an accurate diagnosis. Otherwise, you may inadvertently cause more damage to your plants.

Now if you have really diagnosed a nutrient lockout after a few days of testing, what you have to do is to flush your system. Flushing removes excess salts, stabilizes the pH and gives your crops a chance to ‘breath’ and reboot their nutrient uptake.

Nutrient lockout is common in hydroponics systems because salts will eventually accumulate in the water as we continue to add more fertilizer to the water.

Left with no other choice but to add more nutrients, unused salts in the solution will eventually change the pH level of the nutrient solution, and this causes the lockout.

You can use pure water to flush out your system.

During this time, it might be a good idea to perform a general inspection of the entire system.

Check the pipes, drains, and pumps. Blockages, fungal growth and other common issues can also cause problems in the long term, so use this ‘break time’ to make sure that your hydroponics system is working as intended.

Preventing Nutrient Lockout In the Future

We don’t like having to treat our crops frequently. Nutrient lockout is serious business and one run-in with this problem is enough for an entire season. There are ways to prevent this problem.

1. Use solutions that buffer the pH level of the water. High quality liquid fertilizers are often equipped with a separate buffering formula that helps take care of the pH level of the water so the addition of the nutrients will not ruin the balance you’ve been working hard to maintain.

2. Use flushing solutions that reduce the stress on the plants and the system as a whole.

Flushing solutions specifically remove excess salts from the system as they are (re)circulated. While plain water flushing can also accomplish this, you will get better results when there are active compounds working in the system.

3. If possible use RO or reverse osmosis water. Purified water has reduced levels of commonly occurring chemical compounds that may also be impacting the chemical balance of your hydroponics system.

4. Perform daily EC and pH level monitoring of your system and make sure that you record the data. Recording the data will allow you to observe trends over weeks and months, and the normal average can be computed using this information.