Miracle Gro?... seriously? Seeing that he posted in this forum (Organics) I presume he wants an organic plant food. While I realize that MG sells some kind of organic liquid plant food which is beet molasses, if I remember correctly, it is still lacking in various essential nutrients and generally isn't recommended for cannabis.
What exactly are you looking for; a dry plant food or would you prefer bottled liquid organic nutrients? What kind of medium (or soil) are you using and have you already got them plants in it? Are you planning to transplant in the future?
If you're using a quality, rich soil that doesn't require much additional nutrition for a couple weeks and you plan to transplant soon enough, then you might consider dry plant foods. Espoma Tone products for example are very good complete plant foods, they are inexpensive, and you can find them at virtually any hardware store or garden center. I would recommend Bio-Tone Starter Plus for vegetative growth, or Plant-Tone. Then if you're going to transplant before bloom you could use their Flower-Tone mixed in and perhaps some high-P guano later on. These are more slow-release type plant foods, but they are quite complete, best used with a rich, nutritive potting soil. Be sure to get some dolomite limestone to mix in before transplanting also, as you're likely to need that either way. If done correctly all you'll need to do is water with nothing else required. Some blackstrap molasses in the irrigation water wouldn't hurt nor would an actively aerated compost tea here or there, but you shouldn't experience any deficiencies if you're growing a good strain that isn't a pain in the ass or a nutrient-hog.
You can also top-dress with the dry plant foods and guano every few weeks or so to prevent any problems, or if your plants are in their final containers already and showing any deficiencies.
Otherwise if you'd prefer bottled liquid organic nutrients, good old Earth Juice has never let me down. It's not expensive and it definitely works if you know how to use it. I would recommend at least getting the Grow, Bloom and Catalyst formulas. Microblast is good to have but you wont really need it unless you're growing in a strictly soil-less mix that is lacking the trace elements. Again, you'll definitely want to get yourself some dolomite limestone to mix into your soil. The dolomite provides calcium and magnesium and also neutralizes acidity to keep the soil pH where you want it to be.