Interesting information here from this website:JR Peters Jacks Fertilizer comparison to Scotts Miracle-Gro Review Article
I've been using Jack's Professional aka Jack's Classic All Purpose 20-20-20 for many years. You can water virtually all of your garden with this fertilizer! I use it for both outdoor & indoor plants. I've even used it to revive part of my yard that was dying! It can also be used in both soil & soilless mediums. If you are unsure on how much you should use 1/2 of recommended dose is a good start. If your plants start to claw you are feeding them too much. If they start to fade in color you can probably feed them a little more. You can also use this as a foliage spray (use about .25 normal dose). If your plants are turning yellow or fading in color this will brighten them back up again!
It's a shame this is not sold anywhere where I live. But it is available on Amazon. Jacks Prof 77010 General Purpose Fertilizer, 20-20-20 Fertilizer, 25-Pound