Joel, I would strongly recommend using Eleanor's VF-11. Contains calcium and all of your other trace elements, etc.

Here is a link that might be useful: Eleanor's VF-11

Hmmmm. The guaranteed analysis of the primary macronutrients (NPK) in Eleanor's is Analysis: 0.15 - 0.85 - 0.55 This is less than 1% of ANY of the majors. 1/8 of 1% N, 7/8 of 1% P, 1/2 of 1% K. This is EXTREMELY low in fertility. Since I cannot find the rest of the analysis, I'm going to guess the rest of the nutrients are probably nonexistent or nearly so. Did you find anything to show the % of Ca, Mg, and the minor elements. I'm interested in just how much of these elements it contains. Would you share your source of information, please?

Joel - your answer is pretty complicated, but I'll try to explain it in as easy to understand terms as I can. I have to start with where the N comes from in fertilizers, because of its effect on what can be used as a Ca source.

There are plenty of sources of water-soluble nitrogen, some of which only supply nitrogen - like either urea or ammonium nitrate. For the rest of the nutrients, though, there are far fewer choices. In fact, the only source of Ca for water-soluble fertilizers is calcium nitrate. There is also typically only one source of potassium, potassium nitrate. Magnesium is supplied either as magnesium nitrate or sulfate. Because there are such limitations in the number of fertilizer salts that can be used to blend various fertilizers, the ratio of the 5 macronutrients has a direct affect on the percent ammoniacal nitrogen in the fertilizer.

To give an example, fertilizers that have good amounts of calcium tend to also be high in nitrate, because (noted above) calcium nitrate is the only water-soluble source of calcium. Fertilizers that are high in phosphorus are often also high in ammonium because phosphorus is usually supplied as monoammonium phosphate.

Certain fertilizers generally cannot be mixed at high concentrations. Fertilizer compounds containing sulfate, (for example magnesium sulfate), are not compatible in solution with calcium nitrate because a reaction occurs where insoluble calcium sulfate (gypsum) will form as a precipitate (solid). If a blended fertilizer contains both calcium and magnesium, then the sources have to be calcium nitrate and magnesium nitrate. Similarly, calcium nitrate and monoammonium phosphate cannot be mixed in the same concentrated solution because insoluble calcium phosphate will form as a precipitate.

Sorry, but you asked. ;o)

The short version is that the chemicals used in soluble fertilizers tend to cause Ca to precipitate (fall out) of solution as an insoluble solid where is if no value to the plant, so why include it?

A few fertilizers, like Foliage-Pro 9-3-6 DO contain good amounts of Ca and Mg in the proper proportions. It should be an excellent fertilizer for houseplants.

Al

One of the problems with calcium is that it is held and dispensed within the organic matter sector of soil, so it cannot be provided entirely by supplements. Interesting that we humans who want more dietary calcium face a similar challenge: supplements can help, but dietary calcium processed by the body is essential.

With indoor plants, such small amounts are needed that they can usually be provided via timely repotting or topdressing with fresh potting soil. I often give my plants a spoonful of vermicompost once or twice a year -- or maybe a few pinches of seaweed meal -- for micronutrient boosts. A micronutrient fortified plant food would probably work as well.

Here is a link that might be useful: my website

Al, I have an old PDF I printed out in 2005 which was produced by Dyna-Gro (the maker of Foliage-Pro.) Unfortunately I can no longer find the original web source, or I'd link it here. It is a comparison chart for various fertilizer brands. (It does promote Dyna-Gro products as the most complete fertilizers for micronutrients, but it does seem to have a pretty fair analysis of many other brands.) The chart claims that calcium, magnesium and the other minors are missing from Eleanor's VF-11.

By the way, where did you find Foliage-Pro? I've seen Dyna-Gro Liquid Grow and Liquid Bloom in catalogs and whatnot, but the only time I've ever come across a mention of Foliage-Pro, before you started talking about it here, is on this same chart.

I hope I'm not getting to far off the path here, Joel? Let me know, please?

Hi, Karen. I don't want to link you directly to it, but just use the search words Foliage-Pro 9-3-6. You'll get multiple hits & be able to compare prices.

I'm pretty well set in my fertilizer program, but I'm really excited about it (the 9-3-6) for you guys. (I ordered a gallon of it to try anyway, though) There may be other soluble fertilizers that offer the same 3:1:2 ratio with the secondary macros and all the minors, that I don't know about, but this will be a good one, and about as easy and fool-proof as it gets.

Al

Al, don't worry. I followed the main line of your information (enough memory of highschool chem to get the drift).

Miracle Gro is probably as much used as it is mainly due to the media hype (advertising) it gets, though it does contain - according to the label - many micronutrients, along with the NPK and magnesium... just no calcium. LOL

I've seen many outdoor yards and ornamental gardens that seem to be doing very well on Miracle Gro as a foliar and soil fertilizer.

Perhaps, though, there are better formulations for house plants. I'll check out Foliage Pro. Thanks for recommending it.

Seems to me that in the longer run, the lack of calcium in containerized house plant soil is likely to be detrimental. Because even with plants that you purchase, that got a good well-nourished start in a commercial nursery, eventually the Ca in the original nursery root ball will be used up.

J.

Hi, Joel. You're right. Even though Calcium (Ca) is generally found in plant tissues at about 1/10 as much as N. it is extremely important. Ca is virtually immobile in plants (this means the plant cannot rob it from old leaves to help make the new leaves, like it can do with Nitrogen), so plants need a continual supply of Ca as new leaves form. The stability and function of cell membranes requires Ca to act as sort of a "glue" in the form calcium pectate, which binds adjacent cells together. If adequate amounts of Ca are not transported during cell formation, tissues become less stable and prone to disintegration.

As a Ca deficiency arises, concentrations of Ca will be higher in older, already formed foliage, so it is the newest growth which first shows deficiency symptoms. Often tip burn and/or twisted or cupped growth are indicators.

Ca also plays a role in activating enzymes and messenger chemicals in the plant, regulating the flow of water movement in cells and is essential for all cell growth and division. It also acts as a buffer when excesses of other elements are in soils, making it an important component of root vitality.

Al

Then how to add the needed calcium if the fertilizer formula you've been using hasn't been providing it? If someone has been rasing indoor plants and has a number of them in a good gowing medium in suitable pots etc, can the watering mixture be supplemented occasionally to provide the Ca?

For example, I understand that drug stores or maybe health-food stores sell a liquid calcium dietary supplement. If so, I'd think it would dilute well in water. Could something like that - which might be pretty readily available these days all over N. America - be mixed in the watering can and used to provide what someone's indoor plants need?

J.

joel bc,

Check BC Botanical Garden or someone who may know of water quality in your area. While I have never seen an analysis for BC well/river water, ground water in the PNW can contain decent levels of calcium.

Schmoo

Joel - if you're using a packaged potting soil, it's likely it's already been treated (pH adjusted) with dolomitic lime, which is a source of both Calcium (Ca) and Magnesium (Mg). If you are making your own soils, you can provide Ca by including either a tbsp of dolomitic (garden) lime or gypsum for each gallon of soil.

Dolomitic lime raises soil pH - gypsum does not. I use both, with soil composition and pH the determining factors. If you use gypsum as a Ca source, since it lacks Mg, you'll need to include a very minimal amount (1/8 tsp) of Epsom salts in the water, each time you fertilize.

Al