Mold in Hydroponic Solution Concentrate

effie4050January 22, 2012

My hydroponic lettuce solution, the concentrate, has a layer of powdery green mold on it. I tried to strain it off, but am uncertain if that is enough? Please help.


I mixed a bag of lettuce nutrient (powder form) into 5 gallons of water, as my concentrate--as per the directions. I mixed it in a 5 gallon bucket and covered it with the attached lid, tightly.

When I came back to mix another batch of solution 10 days later, there was a thick layer of green powdery mold floating onto of the solution. I skimmed it off and put it, uncovered, in the sun.

1. Do I have to dump the solution?

2. What can I do to prevent it in the future?

3. Should the plants that have already been fed with this solution be destroyed?

Any help or information that you can provide will be GREATLY appreciated.



Thank you for reporting this comment. Undo

It's useless to strain it, because some mold will always penetrate the strain's holes.
You may use the solution to water your non-hydroponic plants, grass, flowers or some trees.

Always clean your bucket with bleach before filling it with the stock solution.

Put your solution always away from sunlight. Mold grows with sunlight, in dark conditions it can't grow.

It's better to prepare 1 - 2 liter of concentrated solution. Five gallons is too much, unless you have a lot of plants.

If you can, use distilled water to prepare the concentrated solution.

You don't need to destroy your plants, try washing the entire system.

And check the pH of your concentrated solution, it should be acid.

    Bookmark   January 22, 2012 at 4:40PM
Thank you for reporting this comment. Undo

First are you sure it's a mold, and not just residue from the dry mix? There is often a powdery residue left when mixing dry nutrients.

Second, that is a mold it will be extremely hard to get rid of because just one spore starts it all over again. Also mold does not need light to grow, I'm sure jamesvlad was thinking of algae winch does need light. It's always recommended to keep your nutrient concentrate (even solution) in a cool dark location for that very reason.

(1) If it is just a residue left from mixing, then it wont mater. Though it would indicate your nutrients didn't mix correctly.

(2) If it is alage, then just skimming it off, and keeping it in the dark is all you'll need to do.

(3) If it is a mold, you'll likely never be able to get rid of it from your concentrate. I cant really think of a safe way to even try unless you tried mixing in about 1-2 cups of 3% hydrogen peroxide (H2O2) per gallon. I use it a lot in the nutrient solution itself, but have never used it in a nutrient concentrate. I just don't have any idea if it will affect the mineral elements in the nutrients being so concentrated. If it is a mold, and in your concentrate, you'll just keep spreading it to your plants every time you use it.

If you aren't sure, I would recommend to take some pictures of it, then e-mail them to the nutrient manufacture to see what they think. Even if they cant tell you for sure what it is or how to fix it, they should at least be able to tell you if it's normal or not.

    Bookmark   January 24, 2012 at 6:10AM
Thank you for reporting this comment. Undo

Also this may be obvious, and I know you said you mixed per instructions. But are you sure? Generally nutrient concentrates need to be mixed into separate parts. Most one part (complete) dry mixes shouldn't be mixed as a liquid concentrate.

    Bookmark   January 24, 2012 at 6:20AM
Thank you for reporting this comment. Undo

Also, remember most molds will not harm a person. That green mold that grows on bread? It may not be pretty. It might not taste good. But, it won't hurt you to eat it. Same thing applies with most molds (like 99% of them) Not to mention its in the water which you're not going to drink anyway and it unlikely to cross into the plant material so you needn't be too concerned with it.

    Bookmark   January 24, 2012 at 10:43AM
Sign Up to comment
More Discussions
Pepper Plant Fruiting
Hi, I am wondering if I can keep continuously fruiting...
New to Hydrophonics
Hello all ,Im new to the Hydro thing. Im going to start...
Switchin on/off cycles and wheather it should be gradual?
Hello, I was recently asked if it effects the plant...
Jeremiah Landi
coco peat as a medium
I have been using cocopeat for a very short while,...
PVC Tower System - Adding oxygen mid-stream
I have built my first hydro system from 4" PVC...
Sponsored Products
Mature Red Wine Glasses Set Of Four
Classic Hostess
Home Decorators Area Rug: Revolution Black 6' x 9'
Home Depot
Rotaliana | Flow Ceiling Light
$562.50 | YLighting
Round Bowl Pendant W / Cylindrical Finials
Brown Light LED Desk Lamp
$149.99 | FRONTGATE
Modern Concealed Thermostatic Shower Faucet Dual Control
Hudson Reed
Cold-Water 32-Oz. Laundry Liquid - Set of Two
$9.99 | zulily
Concentric Geometric Upholstery Fabric in Sage
$21.00 | FabricSeen
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™