Fish pond water

So i have a koi pond and have had good success watering my vegetables outside with water from it. Now that i am doing my first indoor cannabis grow i am going to try using it on a couple plants. Probably one watering a week, weeks 3-6.
My question is there a way to test this water other than sending it to a lab to determine fertilizer content.

4 Likes

TDS and EC meter. It won’t tell you exactly what’s in it but it will give you the ppm so you can keep your feedings in the right ranges.

4 Likes

Thanks i will try that.

3 Likes

I used aquarium water before but something to think about is any microscopic bugs in the water will be transferred to the indoor grow area, ie fungus gnats, spider mites, etc. If you are bound and determined to use the pond water. I’d invest in Neems or DE.

2 Likes

Thanks hiwayman i had no idea spider mights would get inside in the water. Guess that idea is out the window.

1 Like

I’m definitely unsure if they live in water lol, but I guarantee some larva are in that water and I’d hate for you to be fighting bugs all grow. Easiest way I found is go to Walmart and get a cheap 5 gal bucket and small, cheapest aquarium air pump/airstone. I run the pump and airstone in the water for 24 hours to get rid of the Chlorine in the water. Works for me, so just an idea.

I was not really doing it for the water. Just had good success using the koi pond water on plants outside. We have good well water and a 275 gallon inside tank for temp equalization and ph adjustment. Going to add a circulation pump to the system soon to make sure nothing settles out.

1 Like

Pond water you’d have to worry more about algae, bacteria, and other pathogens. Fungus gnats and spidermites usually come in on your clothes or from other plants or people. Most insects that live in ponds or still bodies of water do not like the same environment as cannabis so not a risk in that aspect.

A good aeration and you’re good to go though. Aerate for 24 to 48 hours before use and it kills all the anaerobic bacteria and as long as you don’t over water and let the soil dry between waterings algae won’t be an issue either.

2 Likes

Aireating seems to be a common recommendation guess i will drop some airstones in the tank and hook up a pump.

It gives the roots oxygen too so it’s wins all around for aerating.

I aerate all of my feedings and even most of my plain waterings just because I like that boost of oxygen getting to the roots.

1 Like

ya I figured something would be in there, just didn’t know exactly what. I personally wouldn’t risk it, but to each their own lol.

I have used pond water for 43 years and have had not had any problems. but like you say, to each their own.

1 Like