Is the MSU repotme liquid orchid fertilizer safe?

[Plantcrazed101]

Hi y'all,

I have been wanting to experiment with my fertilizer a bit, since I've only been using 20-20-20 fertilizer and my violets have been showing signs of PH that is too high despite regular repotting. My orchids don't get fertilized as much, but I imagine they may be suffering too. So I went online and found MSU fertilizer in liquid form on RepotMe, and ordered some.

I'm really worried though!!! I read all these horror stories and then found out that MSU isn't actually the one making the fertilizer? So should I just return this liquid fertilizer? I really don't want to kill my plants or have fertilizer that never ends up getting used because there is only one plant that likes it :/ What do I do?

[estación seca]

"MSU Fertilizer" is a formula developed by people at Michigan State University years ago. Different people make fertilizer using this formula. Liquid MSU is just the powder dissolved in water. You are paying for water.

Go to your water company's Web site and look up your water quality report. All water utilities in the US are required to provide this information. Find the pH and dissolved solids content of your water.

If you have alkaline water, neither your violets nor your orchids may be very happy with it. You can buy pH paper to test the acidity of your water after you mix it with your fertilizer. You can add vinegar to make your water more acid or less alkaline.

[Plantcrazed101]

OOPS!! I meant to say PH that was TOO LOW! My apologies.

I don't use tap water, I use reverse osmosis water, so I'm not sure how to go about making the water more alkaline? I was hoping by getting the MSU I wouldn't have to mess with the PH of the water and just know it's at the right PH. I did test the PH of my fertilizer with some pool ph testing strips I happened to have and it was quite low, it looked like according the color chart on the bottle that it was lower than 6.

[Ray]

There is nothing wrong with the pH being lower than 6, unless it's a LOT lower. The preferred range for most orchids is 5.5-6.5, with variation as much as one full unit outside of that not being particularly bad.

Plus there is the fact that the pH of the applied solution is not nearly as import as the pH within the potting medium, which is affected by the potting medium ingredients and the plant itself.

To test that, water normally with your fertilizer solution, and let the pot completely drain. 30 minutes after that initial irrigation, trickle some of your RO water over the surface of the potting medium, and collect the pour-through. The pH of that is what's important.

[Plantcrazed101]

I see...my potting medium for the violets and some of the orchids is straight perlite. Does perlite have a low PH?

[estación seca]

The pH number represents the amount of acid in a water solution. Completely pure water with nothing at all dissolved in it has a pH of 7, so this was defined as neutral, neither acid nor base. If the water has more acid than does pure water, it has a pH number smaller than 7. If it has less acid than pure water, it has a higher pH number than 7.

In actuality, distilled water open to the air here on Earth is slightly acidic, because carbon dioxide from the air dissolves in the water. When this happens the carbon dioxide forms carbonic acid. The amount is extremely small, but it is enough to lower the pH / make the water more acid.

Solids don't have a pH because they aren't dissolved in water. Your plants' roots experience the pH of the water in the potting soil, not the solid part. This is what Ray is talking about. The pH of the water in your plants' containers will depend on your watering solution, the plants' roots, and any organic matter or microbes that have wound up in the container since you repotted.

Most potting mixes contain things that will dissolve in water poured through them, which can affect the amount of acid in the water. The water you pour through your pot has an amount of acid in it, and that is what your plants care about.

Perlite by itself doesn't affect the pH of the water poured through it. It may come in the bag with other compounds in the perlite particles that will dissolve in water and change the pH of the water poured through the perlite. This is one reason a lot of people recommend rinsing anything that will wind up in a potting mix.

Most of the time, organic matter in wet places gets broken down by microbes into compounds that make the immediate environment more acidic. A bog plant will usually be an acid lover.

Very dry environments feature constant evaporation of surface water, which draws minerals from beneath the surface, and concentrates them. This tends to make a very alkaline environment. This is what most desert succulents expect. Desert plants are highly susceptible to acid-loving Phytophthera rots in acid environments, like a peat-based "cactus mix" that has sat in the container for years past the proper repot date. I think this is a major reason people think cacti are hard to grow.

If your pH measurement is off the scale of your pH paper or test kit, there is no way to tell what it actually is. You need to get pH measuring paper or solution that measures levels below 6. If you are using MSU fertilizer intended for pure water, it is highly likely your pH is fine, but you will know more if you actually measure it.

[naoki]

I wonder how they are preventing the precipitation. Their description of the product is sketchy; it says 13-3-15 8Ca-2Mg (which should be for granular form), but from their instruction, the stock liquid solution should have only 1.6%N.

[Ray]

Naoki, RepotMe is labeling it illegally.

Yes, the powder is 13-5-15, and they are dissolving one pound of powder in a gallon of water, so that one ounce per gallon will give you 125 ppm N.

Buy a quart of their liquid for $13.80 plus what I understand is exorbitant shipping costs, and you get 32 gallons of 125 ppm N fertilizer. Or... Buy a 2 pound jar of the powder from First Rays for $12.50 (plus actual shipping costs) and you can make up about 250 gallons of the very same solution.

[Lady Oscar]

Originally Posted by Ray

Buy a 2 pound jar of the powder from First Rays for $12.50 (plus actual shipping costs) and you can make up about 250 gallons of the very same solution.

Sorry to diverge from the topic, but I wanted to put in a plug for First Rays in terms of shipping. Repotme's shipping to Hawaii is impossibly high, which drives me nuts, particularly since many orchid-related items on Amazon (my usual lifeline here :-P ) are apparently via Repotme.

My KelpMax from First Rays (which I think is contributing to my poor root-rotted Cattleya not being killed by me so far!) had a completely reasonable shipping charge and still arrived within a week, I assume because they were flexible enough to ship via a method where Hawaii wasn't a problem.

[Orchid Whisperer]

I agree with Ray regarding not paying for water and not paying more than necessary for shipping. Why would you do that?

I have looked many times at the Repotme website. I find their high prices and shipping costs off-putting. JMO, people will always shop where they want.