I don't use earth boxes so I can't comment on mixes for them, but as far as the Miracle Grow mix or any other mix that has fertilizer added, the 'feeds for 3 months' is kind of a joke.

There is a very small amount of fert in the mix and most of it will leech out within several waterings. When you consider that these mixes will be used for light feeding indoor houseplants as well as heavy feeding outdoor vegetable crops and everything inbetween there is no realistic way for the manufacturer to tell how long the fertilizer will feed our plants.

It is just a marketing gimic.

Fertilize your plants according to whatever instuctions you have and ignore the fert in the mixes.

Also, for a long term fertilizing solution consider a liquid fertilizer that is applied with waterings. This provides a much more consistent feeding to the plants over the granular type which are better suited for in ground plants. Also consider using organic liquid ferts over synthetics as the synthetics usually have salts in them which can build up over time (if you use terracotta, you will actually see the whitish stains on it after a season of synthetic fert use). The organics have the added benefit of much lower risk of 'burning' plants from excessive amounts being used.

Good luck and happy growing.

Thanks for the replies! So, klv13440, are you saying that Miracle Grow Potting Mix should be fine? Or are you saying that anything including Potting Soil should be fine? I went to Wal Mart but couldn't find any Potting Mix there. I had gone hoping to find the "Sam's Choice" potting mix but had no luck. I would love to find some cheap generic brand of potting mix, but I'm just striking out.

Yes, Miracle grow works great but regular potting soil is to heavy and will smother the roots of plant.I found the generic brand called gardeners choice out in the parking lot with the play sand it's 7.95 for a bag 2cubic feet and that fills the earthbox. If your Walmart does not have it you could try Lowes or Home Depot. If all else fails try making your own-- I found this in another thread
3 gallons pine bark.
1/2 gallon peat
1/2 gallon perlite
handful lime (careful)
1/4 cup CRF
1 tsp micro-nutrient powder or a dash of manure
I am going to use this in a larger amount. I broke it down and it will cut my soil bill in half!
Hope this helped

Thanks, I've been to Wal-mart, 2 Home Depots, Lowe's, OSH, and a local nursery. I might check one more Wal-mart and go with miracle grow if I don't have another choice (it's a bit expensive). I've thought about mixing my own but with such bad luck trying to find mere potting soil I don't have much hope for finding everything needed for that.

So, I should add a strip of time release fertilizer to the mircale grow potting mix even though it has some fertilizer in it as username5 suggets? I just want to be sure that's appropriate for an Earthbox, don't want to burn my veggies.

Hello Joel,

Don't worry about the Miracle grow with the fert in it. It works just fine. I have used it with the fertilizer band of the granulated stuff (whatever is cheapest just make sure all 3 numbers are between 5 - 15) and it works great. Make sure that you cover the box so that the band of fert does not get wet and burn the roots. Please let me know if you have any other questions. I have written a guide on making your own if you do not already have it. The link is below.

Thanks,
Joe

Here is a link that might be useful: How to make an earthbox guide

Thanks so much for the replies, I think I'm finally ready to get started. And thanks for the guide jmalt31, I used that to make my homemade box earlier this week :)

Planted my corn today in my homemade Earthbox. I can't wait to see it grow in to stalks, but I'm a little concerned about the quality of my homemade box. I picked up some containers that got bigger as they got taller, but I didn't realize it until I had already cut one. In order to make the one fit in to the other I had to cut some slits in the sides to give it some wiggle room. It seems okay though, I packed soil on top of the gaps on the sides in the hopes that nothing would fall through there. I guess I'll know how I did in 7-14 days when the seedlings are supposed to pop up :) I'm planning to grow tomatoes in my retail Earthbox when it arrives.

I see what you guys mean about the potting mix with fertilizer, I bought a 3 cubic foot bag of Sta-Green potting mix today that says it's supposed to feed for 9 months, but the numbers were all decimals (.14-.11-.08), much lower than the recommended 5-15 range.

That was last year. This is 2007.

How about an evaluation of Sta-Green from Lowe's as the potting soil of choice for tomatoes as augmented with dolomite and rock phosphate?

Thanks in advance.

How about an evaluation of Sta-Green from Lowe's as the potting soil of choice for tomatoes as augmented with dolomite and rock phosphate?

I responded to the Sta-Green question in the other thread you posted this in.

In this thread I will just ask what the purpose of rock phosphate is? Rock phosphate is a rock powder which releases nutrients slowly (years). I don't understand it's purpose in a container mix. Superphosphate, triple super phosphate are rock phosphate treated with acid to make the nutrients available faster and would be more suitable.

But, your best bet in an earthbox is simply using a complete, granular fertilizer rather than trying to get each nutrient from a specific source. Espoma makes a nice, complete fertilizer that is mostly organic with some faster acting synthetics included as well. Of course, there are others.

Sir:

I went to the Espoma website and tried to find both product and dealer.

The nearest dealer is about SIX HUNDRED MILES away. Think I will look for another brand of suitable granular, non-water soluble complete fertilizer for tomatoes with at least 5-5-5 rating. Thanks.

The nearest dealer is about SIX HUNDRED MILES away.

There isn't anything special about the Espoma, another will do fine. Espoma is what I use because it is a complete fertilizer, most of it isn't water soluble immediately (and you don't want purely water soluble in an earthbox) and it is easily available for me.

600 miles away is the nearest? Wow. If that were the case for me I probably would look for something else as well.

BINGO!

Espoma Garden Lime product found.

Went to my speciality nursery store. Brand-new product. Been in the store one week.

Label says "Safer than Hydrated Lime."

Goes into the mix today. Bought seventeen (17) Early Girl variety tomatoes. Will plant two (2) faux earthboxes and a bunch of five-gallon black plastic containers just to see how they do, comparatively speaking. Also bought five (5) very large tomato plants, some showing blossoms; will put them into the ground and hope for tomatoes before Mother's Day. My wife says we will be tomato poor. All I know is that I am determined to find a winning formulation for growing great tomatoes so that I can pick them fresh and ripe off the vine or put them in a southern-exposure window sill for finishing.

No phosphate amendment or supplement used. Granular fertilizer. Wish me luck. Thanks for your advise.