switching fertilizers!!

[orchid-asmr]

hello all!
I am currently using a fertilizer brand called Grow More (20-20-20). I have noticed that once in awhile i would burn my orchids roots with this especially when it started to get clumpy (its a powder). I assume its because moister has gathered in the container somehow and now the salts have a accumulated and harder to mix in the water. As much as i hate myself for it I do use tap water which in soCal is probably heavy with calcium and magnesium and this fertilizer doesnt have calcium or magnesium which im happy about, BUT it does use urea as its main source of nitrogen which i have heard is not good for orchids as it doesn't go through the nitrogen cycle and properly break down for them to actually absorb it which is another reason why i think my orchid roots are burning. And this is why I am looking for a new fertilizer! I want to try the MSU FEED ME! (13-5-15) by rePotme.com but it has an 8% dosage of calcium and a 2.6% of manganese. Do you think it would be ok even with the extra calcium? Or does anyone else have any other recommendations!

Also sorry if this is not the right thread to post this! im not too sure!

[Dollythehun]

I use that and I still supplement with Cal-Mag. No problems.

[Roberta]

A thought with regard to the fertilizer. How much are you using? If the label says 1 teaspoon per gallon, I would suggest 1/4 to 1/2 teaspoon per gallon. Also, invest in an inexpensive pH meter, or the test paper. A TDS meter is also a good idea. I know a whole lot about southern California water... first, it is highly variable - where I live, the solids (TDS) are not too horrid - typically about 200 to 350 PPM. But in some areas it can be 500-600 or more (turn on the faucet and rocks come out...) The primary constituent throughout the area is calcium carbonate, which tends to raise pH to 8 or even 9 - 'way too high. The fertilizer alone will not have much effect on lowering the pH to the 6.5-7 range that is ideal for plants (I have found that about a tablespoon of vinegar in the fertilizer water has the desired effect)

I hope that you are not using softened water - that replaces the calcium in the water with sodium, which is horrid for plants. That alone can burn and kill plants!

Knowledge is power... while you can get an "average" analysis from your local water company, what comes out of the tap is so variable that you really need to test it. Your friendly local hydroponic store should have what you need. Once you know what you are dealing with, you are in a better position to adjust your procedures in a useful way.

[Orchid Whisperer]

Your root burn is more likely due to the water quality than the fertilizer. This assumes you don't use fertilizer at the full strength recommended on the package (try 1/4 strength). Regardless, if your tap water is of poor quality (high dissolved solids) you are likely not getting dissolved solids properly flushed out of the potting medium.

Also, the urea concern is a myth. There is scientific research which indicates orchid roots take up urea and metabolize it internally (research by Martin Trepanier and colleagues, published around 2008), at least as well as other forms of nitrogen. Orchids and other plants have an enzyme, urease, which helps aid urea metabolism by the plant.

Change fertilizer, or keep what you are using, the root burning will improve when you can improve your water quality. Try mixing in rain water, distilled water, or get a reverse osmosis (RO) system. Ray on Orchidboard sells a countertop RO system.

[Ray]

Roberta is definitely putting you on the right track. - how much fertilizer you add to a gallon of water depends, to a significant degree, on how often you feed. I will add that "more" is not "better" with plant nutrients. In fact, more often than not, the opposite is true.

I have a bunch of articles on my website, but you might start by reading this one.

[orchid-asmr]

Thank you all so much youre all too kind!

I do use a lower dosage for the fertilizer. I'm surr my water quality that is one of the main issues. I havent tested it but im getting the feeling its horrid! Definitely going to invest in some water testing tools.

I also just found out that the dechlorinator Ive been using has Sodium Thiosulfate!!!! which is causing the real issues i think.

I wish i could afford a RO system, but alas I am a poor college student , even a countertop system is a bit too pricey for me, through time though!

@roberta you mentioned using vinegar to lower the pH, is a tablespoon for a gallon?

[Roberta]

First, why are you using a dechlorinator? The amount of chlorine (or chloramine) in drinking water is no problem for orchids. (They aren't fish!) And yes, adding sodium thiosulfate is likely to be bad news. Don't use it on your orchids!
My tap water (which I have used on orchids for many years) has a pH of 7.8 - 8 even after I add the 1/2 teaspoon per gallon of 20-20-20 fertilizer. I found that for my water, adding about 1 tablespoon per gallon of ordinary white vinegar dropped the pH to about 6.5, which is close to the range that is good for fertilizer absorption. If you use this trick, get a way to measure pH first. Add about half that, and then measure... add more if needed. Vinegar will do no harm, it's just a form of soluble carbs.

Some orchids are fussier than others with regard to TDS (and pH for that matter) I only recently got an an RO unit, because after 20+ years I wanted to have better results with some of the picky rainforest orchids. (I am a "what can I get away with?" back yard grower) But my Catts, Cymbidiums, and quite a few other things still get plain old city water and do just fine.

---------- Post added at 06:59 PM ---------- Previous post was at 05:46 PM ----------

Thinking about it... how much of the dechlorinator were you using? If just a drop or so it wouldn't be enough to harm, I don't think. But definitely not needed. Also... what part of southern California are we talking about? If San Diego area, the water may be so bad that RO is necessary... tabletop units are quite inexpensive. I think that most of LA and Orange counties have tolerable water for the more more common orchids.

[orchid-asmr]

Maybe, ive been using 2 drops per gallon as it says in the directions. I live in the San Fernando area! Now that im doing a bit more looking i do seem some that are significantly cheaper! Ive always thought you had to make installments and what not and i live in an apt so im unable to do that. Would you recommend any sort of brands?

[Roberta]

Originally Posted by orchid-asmr

Maybe, ive been using 2 drops per gallon as it says in the directions. I live in the San Fernando area! Now that im doing a bit more looking i do seem some that are significantly cheaper! Ive always thought you had to make installments and what not and i live in an apt so im unable to do that. Would you recommend any sort of brands?

I'm not sure what your water is like (I am more familiar with the Orange County area, and south) I do recommend that you get an inexpensive meter and test it (Amazon, if your local hydroponics store is too expensive). For RO units one of the little units that is designed for under the sink should work fine. Do a bit of online research.... Or this one Hydro Logic MicRO Reverse Osmosis Filter - 75 GPD Complete Water Filtration Units Water Filtration & Treatment Hydroponics comes from the outfit that I bought mine from, they're local, items typically received 1-2 days after order. But you very likely can find one for even less money since you probably don't need much volume. You just run the RO water into your container of choice (gallon jug, bucket, etc.) and the waste down the drain if you don't have a place to utilize it (though toilet-flushing comes to mind as one place one could use small volumes) You'll get 2-4 gallons of "waste" for each gallon of pure water, so using the effluent rather than just dumping it is desirable.

The only tricky part is hooking up the source water. If your kitchen sink has a fitting for a water filter, you're home free. Otherwise, you may have to put a T in the cold water line under the sink. (Home Depot, here I come...) Once that's done, easy.

[Lacie]

I don't know much about fertilizers (or dechlorinators), but just wanted to add that Grow More does make a urea free orchid fertilizer (I believe it is 20-10-20) if you are worried about the calcium in the MSU fert.