In most cases, I'd suggest something like Dyna Gro's Foliage Pro or GROW at half strength on a weekly basis. But with larger, permanent plantings (like trees and shrubs) I dose once every spring with Osmocote Plus.

Wow has it been 3 years already, Gary?

I use Nutricote controlled release fertilizer (CRF) and a water soluble fertilizer from a local company. The CRF is at 1#N/cuyd and the water soluble is applied at 100ppm N. The combo is being used by the industry to try to minimize leaching as much as possible.

I use Dyna-Gro Foliage Pro and Pro-TeKt. It has all the major, minor and trace elements. I like to make sure the water is slightly acidic or I get little white things that look like pearlite. I seem to remember reading something about one of the nutrients (calcium?) dropping out of suspension in alkaline water, but I be hard pressed to find it in an article...probably in one of Tapla's posts.

Calcium will come out of suspension if there is a lot of sulfate in the water. Makes calcium sulfate (gypsum)

Can you recommend a granular fertilizer that I can use?

Liquid or water soluble (granules or crystals dissolved in water) actually work more efficiently for container plantings than do granular ferts. And I only use the CRF's on permanent outdoor plantings at the start of the growing season, as they last 4-8 months, depending on product and temperatures.

My Foliage Pro formed crystals in it, is it still usable?

I use https://www.amazon.com/Nutricote-Release-Fertilizer-Pounds-Orchids/dp/B00DFIU3HE

But you should be able to find it locally. I get mine at a landscape supply company in Gardena.

Gardengal, where do you get info that CRFs aren't efficient for containers, because there is a bunch of research showing lowered leaching and improved growth by using both and pretty much every wholesale grower uses both.

Oh ok, gotcha like a slow release nitrogen granule for lawns. Yeah those release curves are not very controlled for use in containers. Any granular fertilizer should be a controlled resin coated granule.

On Amazon, the description for Nutricote Total 18-6-18 says it "can be used alone, but regular use of a water soluble plant food such as Peters 20-20-20 is recommended".

I wouldn't use 20-20-20 because it has way too much P and it will just leach out the bottom of the pot, polluting the ground below. Since most suburban gardens already have toxic amounts of P, it's especially problematic.

The reason Dyna Gro's Foliage Pro is so often recommended for this purpose is that in addition to the full compliment of minor or trace nutrients (which many other prepared ferts lack), it delivers nutrients in the ratio that most plants prefer or utilize most efficiently (3-1-2). Even Osmocote Plus delivers nutes in a very similar formulation so you are not over-applying any specific nutrient unnecessarily.

I do 20-20-20 1 tbsp per gallon with 1/8 tbsp of Epsam Salt at every watering. I water with only water every two weeks to flush out deposits. It seems to be working but I just got started in horticulture so I may be wrong. (Also my soil is prepared with Gypsum at 1tbsp per gallon of soil).

For an all encompassing solution without the weird stuff I have to do, do Foliage Pro because it has all of the above in it. Maybe 1tbsp per gallon of water, maybe less.

Nil, does the pH affect the calcium? My tap is about 40mg/l, too much? I was using some battery acid (sulphuric acid) to lower pH of water...I guess that had more to do with the calcium precipitation than the pH?