I've been using Miracle grow all purpose soluble plant food for a few years now. This version is spot on. It is granular so this two kilo tub can make 720 litres of liquid plant feed! I have a 5 litre watering can so that makes 144 cans full! Not bad at all. (13.5 grams dissolved per can)
This is an all purpose feed as it contains all the things that your plants in general need to grow well. The ratio of main ingredients (in this) are 24:8:16, which means there are 24 parts Nitrogen, 8 parts Phosphorus, 16 parts Potassium (when it's dissolved in water) as well as smaller amounts of trace elements such as Iron, Magnesium, Boron and Manganese! These are basically all the nutrients your plants need to grow well.
Just a quick explanation of the three main ingredients in here. . .Nitrogen, Phosphorus and Potassium. You will find these in differing quantities in all fertilizers. This is an all purpose fertilizer so there is a similar amount of each.
Nitrogen-Makes plants grow vigorously (foliage) and green! This is why lawn fertilizers are high in Nitrogen.
Phosphorus-Promotes healthy, strong root development. This is why bulb fertilizers are high in Phosphorus.
Potassium-This aids flower size and colour (blooming) and helps fruiting! There is very rarely more of this than the other two as plants only need a little help doing this.
So when you see N:P:K 24:8:16 that's what it means and these numbers can be different for other fertilizers of course depending on what they're for!
So, I use this fertilizer every two weeks from about May through to September. I mainly grow flowers and some veg. My flowers definitely benefit from it. The flower heads are bigger, the colours appear brighter and deeper and dare I say. . .a stronger scent? :-) The root systems are more prolific and stronger, thicker. Foliage is great, a lovely deep green and large leaves, good stem growth.
I personally don't just depend on this as it is a quick shot of nutrients that doesn't last long. That's why it's a two week application. Soil preperation before you plant out is the key to a successful garden. Digging the soil over about 18 inches deep and incorporating organic material such as rotted manure or Fish blood and bone in early Autumn will give your soil a good chance to break down further before planting out later on.
One other thing. . .I don't use Miracle grow on seedlings. I let them grow of their own accord and develop a good root system as they have enough nutrients in the compost they're growing in for a good few weeks. Once they are well developed I use half strength Liquid feed (7 grams per can) and once they're planted out I will use full strength dilution.
So yes! I can absolutely recommend Miracle grow soluble plant food for watering around the root area and over foliage. . .backing up your usual growing methods of course. Don't tell the neighbours though!