Fertilizer Expiration Dates & RO Water

[lycaonpictus]

I have recently had the great good fortune to "inherit" the large wardian case built by Ocelaris a few years ago (and detailed as part of this thread). It is truly a masterpiece, and I am so lucky to have it!

Along with the case, though, came two questions!

First: Ocelaris also gave me a container of granular fertilizer from First Rays Orchids for use with RO water. It has obviously gotten wet in the past, as it is pretty well clumped together. Is it still usable as fertilizer, if I crumble it apart and mix it with RO water? Or does the previous wetting ruin it?

Second: This beautiful case comes with a clever fogging system that involves water sitting for several days in a big 5 gallon bucket. I have always used RO water for fogging to avoid getting mineral stains on walls and plants. However, I read on another thread here about how RO water will change pH due to interaction with the air if you let it sit out. Is this a problem with fogging water?

Thanks, everybody! I'm hoping to get some pictures of the system up and working real soon!

[billc]

I've used wet/clumped fertilizer with no issues. Just use the same amount you would normally use. You may have to swish around your measuring device to get all the fertilizer off.
I have no experience with foggers, but I can't see it being a real issue as far as the PH levels.
Good luck with the new case. I remember his posts when he was building it. Your tolumnias shoud love it.

Bill

[Discus]

I suspect no matter what pH the water is sitting in a bucket, it's absorbing a heck of a lot more CO2 the moment you start turning it into a mist/fog! (absorbing CO2 out the air makes carbonic acid and is responsible for making the RO or distilled water "acidic") This is generally pretty mild (like not less than 6 or so) - you can always put a pH meter in there if you're worried.

[lycaonpictus]

Discus -- Not worried, just wondering. The CO2 absorption upon fogging is a good point! Hasn't seemed to bother them so far.

Thanks, guys!

[Ryan.Walsh]

I'm sure the fertilizer is fine. It may not have even been exposed to water per se, but just not kept tightly sealed in a humid environment. Many components of fertilizer are highly hygroscopic and will readily absorb moisture from the air.

Regarding the pH, if you think about it what you are doing is really no different from rain. Rain results from evaporated water (thereby purifying it) that is exposed to various elements in the atmosphere, including plenty of CO2. Depending on your location, rain water will range from a pH of 4.4 (acid rain) to 6.0. I'll bet if you measured the water coming out of the mister it would be quite equivalent to average rain pH.

[Ray]

Yep, powdered fertilizers absorb moisture from the air. I switched from 5#, snap-top closures to 2# screw-tops specifically because of that.

You can no longer use weight for measuring it, but volumetrics (teaspoons/gallon) are still OK.

Concerning RO, the equilibrium with the concentration of carbon dioxide in room temperature air will give you a pH of about 5.7, which is still fine for plants.

[lycaonpictus]

Thanks, everybody, for your answers! Nice to know that the fertilizer is still useful (I use volumetric measuring, so that's fine), and that the water isn't hurting anything.

I've been walking around with a stupid grin on my face for the past week, I'm so excited about this case! I can't wait to get pictures up!

Thanks again!

[Masdyman]

Maybe the feed will be better if it was now diluted in to a stock solution?