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Why Are My Hydroponic Plants Dying? Troubleshooting Hydroponics

Are you running into a few issues with your hydroponic system? Maybe you’ve discovered a bit of green slime taking over the reservoir, or your plants are showing signs of stress. If you are starting to ask, “Why are my hydroponics plants dying?” It’s urgently time to troubleshoot what’s happening in your grow room.

Even if you know how to diagnose soil-based systems issues, you’ll need to learn the signs of common hydroponics problems. The signs are different when growing in a nutrient system, and so are the root causes — no pun intended. 

Without further ado — let’s take a look at some of the most common issues you’ll experience as a hydroponics grower. Everything from algae blooms to pH levels to salt.

The Problem: Algae Slime 

What do you get when you combine heat, water, and light? You get algae growth.

Algae is a common occurrence in hydroponics systems because you’ve created the perfect environment. If you grow with hydro, chances are at some point you’ll have to battle an excess of algae growth.

Algae appears as green, brown, and slimy growth. You’ll find it along the edges of the water, in the lines, and the reservoir. It doesn’t smell nice and proliferates.

The problem with algae in your hydroponics system is that it pulls oxygen and nutrients away from your plants. It can also clog lines and, as it dies, release toxins as it decomposes.

The Solution: Clean, Clean, Clean

clorox bleach bottle. top down.
A deep system clean between grows helps kill algae and other pathogens.

First things first, some algae is expected and even okay within your hydro setup. A little green film around the edges will do little harm to your grow room’s overall productivity.

But, when you start to smell something funky or notice serious slime, it’s time to correct the overgrowth.

A sure-fire way to get algae under control is routine sanitation and sterilization. Cleaning the buckets, reservoirs, and even the tubing between crops will remove the dead algae.

Sanitation is cleaning, while sterilization kills off all unwanted bacteria, fungi, and pathogens. You’ll need both to maintain a clean and algae-free grow room.

Diluted solutions of hydrogen peroxide or bleach are perfect for flushing the hydroponics system between uses. These products kill microbial and algae that may linger from one round to the next.

You can also use common household cleaners and degreasers for basic sanitation during the grow, on surfaces, tools, and other general grow room areas.

There are algae pesticides for hydroponics, but these are costly and only useful for a time. In addition, they wear off quickly and have to be reapplied. With a full cleaning between grows, you shouldn’t need to introduce any pesticides into the mix.

The Problem: Salt Build Up

Ever notice a bit of white crust appearing around the top of your system? This is a signature of excessive salt buildup in your system. Depending on the type of system you run, it could be a common problem you experience.

As water naturally evaporates from reservoirs, open buckets, or even the surface of the soilless growing medium, the solid particles are left behind. Many nutrient solutions contain low levels of salts, so as the water evaporates, these salts are left behind.

While some salt is not an issue, too much salt can change the system’s electrical conductivity (EC). It can also start to damage roots, seedlings, and other sensitive areas of the plant. 

The Solution: Monitor for Evidence, Flush Medium

While not every system is susceptible, it’s always good to monitor for the tell-tale signs of salt buildup. Check around the edges of your buckets and reservoirs and across the surface of the growing medium.

You’ll also want to schedule routine system flushes. In systems with high evaporation (flood and drain is an example), you’ll need to schedule these more frequently than others (like Deep Water Culture).

You can flush with a watered-down nutrient solution (one-third of the usual strength) or specific hydroponics flush formulas. Between grows, you’ll also want to flush the clay pellets or other medium fully to remove any of the buildup. If the situation is dire enough, replacement of the medium may be necessary.

The Problem: Rising pH Levels

At some point, you’ll end up fighting rising pH levels in your nutrient solution. Too much pH and your plants will struggle with nutrient uptake. Too low (which means too acidic) and nutrients become toxic to your plants

There are many influences over pH in a hydro grow room, including tap water, nutrients, electrical conductivity, and overall evaporation. One of the biggest issues is the natural process of your plants absorbing the nutrient solution.

Many growers encounter issues with pH rise in their hydroponic system because nutrients are slightly acidic. So, when you first add nutrients into your reservoir, the system’s pH will drop. But, over time, as your plants absorb these nutrients, you’ll see the pH creep back up.

The Solution: Monitor pH and Adjust Carefully

To manage pH levels in your hydroponics system, you’ll need a digital pH monitor. We also recommend testing your tap water every time (it can fluctuate) and test the system after adding nutrients. Don’t forget to monitor pH daily.

Although pH Up and Down solutions work in a pinch, you’ll want to use them carefully. A little goes a long way, especially with small systems. So start low and go slow. 

Aim for a pH range between 6 to 6.5 for most plants, but always do a little research to precisely determine what pH range works best for your crops.

Expert Tip: Do not experiment with household products like vinegar and baking soda. The pH in these products isn’t consistent and is difficult to manage.

Why Are My Hydroponic Plants Dying? Now You Know

Whether you’ve noticed crusty white salt or too much brown slime, you now know how to identify and to correct these common hydroponic problems. 

If you catch these issues early enough, you can correct almost anything without much damage to your plants.

But, that means you need to monitor your plants every single day. Check the buckets, the reservoir, and the plants themselves for signs of distress, scum, and salt. If you pay attention, you’ll be able to mitigate these issues well before the take over.

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