Water Tray Maintenance

[Radagast]

Hi Folks,

As some of you may know I got my first CP's in April and they're doing fairly well. Plenty of light, water, good temps and decent humidity. I use the water tray method and had quite a shock this morning...

I've done a lot of research and most places I've found say "clean the water tray every few months" to even "once or twice a year." This morning I was using my TDS meter to demonstrate to my fiancée that even a tiny bit of fertilizer increases the ppm of water by a ton! (She uses too much fertilizer to water our non-cp house plants haha). While I was making my point I dipped the TDS meter into my water tray and much to my surprise it read 170ppm!! I shrieked and yanked all the plants out, scrubbed the tray, refilled it and it now reads 1ppm.

Is this a situation that happens to you folks from time to time? How often do you guys clean your water trays?

Thanks!

 

[RSS]

TDS is very misleading, adding proper trace elements into water is good for most if not all plants. Just having a high TDS is not always an issue. I just checked my main flood/drain setup and the water I use for it is at 224 right now. The high TDS is from ferts and is not a concern, the original water was in the sub 50 range pre-ferts. Now tap water at 224 would be of great concern.

In your example I'm assuming the raising TDS is from mineral build-up due to evaporated water and should be monitored like everything else to keep the numbers within reasonable ranges depending on the plants your growing. However, it could also be from medium breakdown or mineral build-up within the mediums both a much bigger issue.

TDS meters are great if used as a measuring tool within proper context. One example would be mixing 1/4ish strength ferts last month I measured the TDS before and after, 50 before 220 after. This is not a bad reading. Using the flood/drain setup as an example, since I know the starting TDS of the water I can use the TDS meter to monitor the amount of "top off water" I need to add to replace evaporated water and keep fert levels constant until I replace the batch.

With all that said I do clean my water trays whenever they look like they need cleaning . I also have a lot of completely closed systems (think vivariums) that have been set up for years without ever having the base medium drained/cleaned/anything. Some of these are lightly fertilized every week for years without any effort to remove the excess mineral build-up.

I have a 12" X 12" tank I'm growing Ceph leaf pulls up in and I'm running a test run with 100% Miracle Grow potting soil to root 4 Ceph leaves (1/4 has visible growth so far) and the TDS in there is OVER 500! And none of the other "rooted" Cephs is showing any signs of distress. I'd guess the really high TDS is simply a matter of the Ferts in the MG leaking into the tray. Or any of the junk in MG leaking out...

Basically what I'm trying to convey is that high TDS is not always a problem, so long as you know what made the TDS high and those minerals are good/neutral for the plants your growing. All this goes out the window with rare or fussy plants as caution should always be taken with those.

 

[Radagast]

Thanks for the advice, I'll keep my eye on it and use the meter once a week and see how the numbers look. Now that I think about it...all of them are brand new plants, and when each of them arrived they had significant amounts of moss and algae growth at the top of the soil. What I've been doing was scraping it off the top and then top-watering to hopefully wash out any excess nutrients that were encouraging the undesirable growth. This could very well be the reason for the increased ppm reading. In addition the bottom of the tray was beginning to get slimy so that may also have contributed.

My ultimate goal is to repot all of them into square pots using fresh, well-rinsed media. I've already done this with the capensis.

 

[Tanukimo]

What kind of water are you using to water your plants? I would be more worried about the TDS of your water source than the TDS of the water at the bottom of your trays, since topwatering usually flushes minerals and other substances out of the soil.

 

[Radagast]

I'm using bottled, distilled water from the grocery store. I test it and it is always 0-2ppm. Which is why I was shocked when the reading was much higher. But again I think it was from getting pots already loaded with nutrients and then flushing them out into the water.

 

[scottychaos]

Another thing to consider..
I have been growing VFT's and Sarrs for 20 years now, using the tray method..
I have never once used, or considered using, a TDS meter! and I never will..
I collect rain water, and have never bothered to test it..
its simply not a concern for me to know its TDS, since im confidant it is low enough..

Basically what I'm trying to convey is, if you have good water (RO, distilled or rain water) you dont really need a TDS meter at all..
you might be over-thinking it! What are you using as your water supply?

I dump my water trays perhaps once a month, but its not on any set schedule..
I mainly only do it if I see mosquito larva in the trays.
If I know we are going to get a nice day-long soaking rain, I will sometimes remove
the pots from their trays to let the rain "flush out" the pots..but I only do that if conditions
are right and I happen to think of it..I dont consider it a "normal" or necessary part of my CP growing..

Scot

 

[fredg]

I have lagoons for Sarracenia etc in a greenhouse so there's no chance they will ever be cleaned out. I may brush them out with a soft brush when I have plants out for their annual haircut but this isn't a definite.
If you're really worried get someone to do a TDS reading from the ground water on a carnivorous plant site.

 

[RSS]

Basically what I'm trying to convey is, if you have good water (RO, distilled or rain water) you dont really need a TDS meter at all..
you might be over-thinking it! What are you using as your water supply?
Scot

If you are using any RO type system you need a TDS meter to know when the system/parts need replacing. DI filters are really bad about going from 10-20ppm to 100-200 ppm in under 25g of output. If you are getting water from fish stores/grocery store/ect its wise to have a meter on hand to verify you are getting what you are paying for. There are horror stories throughout the forums of bought RO water over 200 TDS and a few where the fish stores sold salt water as RO water!

I'd love to use rain water, but down here in TX we are still in a drought!

 

[Not a Number]

Valid arguments on both sides.

Things to consider.

The membrane on RO filters eventually clogs and will just pass unfiltered water. A TDS meter and pressure meter will tell you when to replace the membrane and other filters. If you buy water from RO filtered vending machines you have no way of knowing if the filter is in working order or properly maintained without testing the water.

While Hollywood and horror novels may depict bogs as dead-end death traps filled with stinking stagnant water, many sphagnum bogs are open-ended living ecosystems. Water circulates and drains out - slowly perhaps. And living Sphagnum will absorb many dissolved solids through cation exchange. You might be surprised if you took a TDS measurement from the "ground water" from under the floating Sphagnum mat in a "quaking bog".

Now it is generally accepted that in high enough concentrations around the roots nutrients will have a negative even lethal effect on most, if not all, carnivorous plants. This is no doubt true for just about any plant but the threshold for carnivorous plants is much lower than your typical house or garden plant. The nutrients (mainly nitrogen, potassium, phosphorus, calcium and magnesium) are commonly found in ground water in the form of salts. The easiest way to test for these is with a Total Dissolved Solids meter (TDS). While these meters will normally give you a reading in parts per million (ppm) the meter won't tell which and how much of each dissolved solids are present - just the total.

The answers given most often to "What ppm is safe for CPs?" are usually 100ppm or less or 50ppm or less. You will also find a few long time growers (over 15 years growing) that will tell you they use well or tap water that measures in the 200-250ppm range. Usually you will find these growers top water their plants and not let them stand in water. While these levels are "safe" the problem is that these dissolved solids (salts) will accumulate and build up in the media, more quickly when using trays (the salts have nowhere else to go). Eventually you should replace the medium. Peat moss will breakdown/decompose and release the nutrients contained in it. Plus you can get nutrients introduced by other organisms.

 

[tommyr]

Another thing to consider..
I have been growing VFT's and Sarrs for 20 years now, using the tray method..
I have never once used, or considered using, a TDS meter! and I never will..
I collect rain water, and have never bothered to test it..
its simply not a concern for me to know its TDS, since im confidant it is low enough..

Basically what I'm trying to convey is, if you have good water (RO, distilled or rain water) you dont really need a TDS meter at all..
you might be over-thinking it! What are you using as your water supply?

I dump my water trays perhaps once a month, but its not on any set schedule..
I mainly only do it if I see mosquito larva in the trays.
If I know we are going to get a nice day-long soaking rain, I will sometimes remove
the pots from their trays to let the rain "flush out" the pots..but I only do that if conditions
are right and I happen to think of it..I dont consider it a "normal" or necessary part of my CP growing..

Scot

Agreed! The only thing I do is add a little bit of "Mosquito dunks" to my trays/rainwater buckets to kill the larvae. I may also dump and clean the trays once or twice during the season but I don't have as many trays as some of you do.

 

[SubRosa]

A couple pics of a surprise I found when cleaning out my tray:

 

[tommyr]

Last year I got startled a little when a frog jumped out of one of my water trays! LOL! He ended up coming back though and I left him alone.