What water soluble fertilizers can you mix together?

[Shule]

I often see lists of fertilizers and mineral salts that you can't mix together, but what about the ones you can? Does anyone know any good combinations off-hand?

[mama_lor]

Calcium nitrate (not sure if other calcium salts as well) with phosphates is the only combination I know of that is not so good (even then, you see it sometimes, like in texas tomato food).
For basically all complete fertilizers you don't know the exact composition of the ingredients (you can make an educated rough calculation by the NPK and if it also lists the sulfur content (Compo for example also lists the sulfur content and how much nitrate nitrogen and how much ammonium nitrogen, which makes it definitely easier to guess the exact formula, and is useful overall to see what the pH tendency of that fertilizer is).

[Whwoz]

Look for the same elements or salts and you can generally get away with it ok. By that I mean different potassium (K) (sulphate, chloride) salts won't react with each other and different sulphate (potassium, phosphorus) salts won't react. Would be careful with Nitrates always and always take care when mixing any combination for the first time.

[bower]

Fish emulsion (mostly N-P) and blackstrap molasses (K and micronutrients) (both diluted) mix up well, never explode, and as a bonus, the molasses neutralizes the fish smell.

[Shule]

@Bower
That makes sense. Brown sugar has deodorizing properties; so, it's not too surprising that molasses would, too (even though I've never noticed the same kinds of deodorizing properties with molasses, nor with white sugar).

[Shule]

One time (probably more than once) I mixed zinc sulfate monohydrate and city water. The zinc turned into a solid white rock almost instantly. I make sure to mix that into the soil before I get it wet, now. That makes me wonder what's in my tap water (you're supposed to be able to mix it with water).

I think mixing a different mineral salt with the water before adding the zinc prevented it from turning into a rock.

[Shule]

So, I've been thinking about amending Miracle Gro fertilizer for a while now to increase the phosphorus and potassium content. I figured adding ingredients already found in the fertilizer might be safe. What do you think?

It says 'derived from . . . potassium phosphate'. Do you think adding monopotassium phosphate would be fine?

[mama_lor]

Increasing phosphorous content of soil is fairly futile. It is better to be used bit by bit, as fertigation, especially after transplanting. It will become quite quickly unavailable in soil, reacting with calcium and other things. K content can be however improved, probably the mineral of choice being the sulfate.

[Shule]

Increasing phosphorous content of soil is fairly futile. It is better to be used bit by bit, as fertigation, especially after transplanting. It will become quite quickly unavailable in soil, reacting with calcium and other things. K content can be however improved, probably the mineral of choice being the sulfate.

I prefer to do foliar sprays with a pump sprayer. It's loads more efficient than any other method, and you don't have to worry about soil availability, what it does to the soil, groundwater leaching, etc. I wouldn't be particular about it being water soluble if I were amending the soil, unless it were for containers.

[pepperhead212]

I had something strange happen a few years ago, sort of related to this. I got some hydroponics nutrients, dissolved in water, which I usually don't buy, but the place - Wormsway, if I recall - was going out of business, so I got some major deals, plus free shipping. The type I got was in 2 parts - the basic, plus the "grow", for vegetative growth. I never do any flowering plants in hydro, so these 2 were all I would use, so I mixed some in a small bottle, so I wouldn't have to fool with two gallon bottles every time. Immediately, there was a white precipitate created in the bottle! This made me wonder what happened in the tubs, so I added the base, let it sit for a while, then added the grow, in the amounts I always used per gal, and there was no precipitate formed, sitting overnight, and it would have been visible in a black tub! My guess is that the concentrates together created a higher or lower pH, causing the precipitate, but very diluted in the water, they remain dissolved. So similar things could happen, mixing soluble fertilizers.

[mama_lor]

I prefer to do foliar sprays with a pump sprayer. It's loads more efficient than any other method, and you don't have to worry about soil availability, what it does to the soil, groundwater leaching, etc. I wouldn't be particular about it being water soluble if I were amending the soil, unless it were for containers.

The roots are still the best food delivery system, that's where the focus should be imo, foliar is more for optimizing things after you've done everything else.

[Shule]

I mixed some Miracle Gro and potassium sulfate in water, today, and the result dissolved without creating solid bits/chunks. That's excellent news.