What type of fertliizer in EBs?

Carmel, IN(Zone 5b)

This is my first year using Earthboxes. Does anyone have any suggestions for the type of fertilizer to use with the EB as the recommended fertilizer strip? Everything I've found locally is water-soluble (such as Miracle Grow). Does any one have any suggestions for a good 12-12-12 or something similar that would be good for Earthboxes (I'm using BocaBobs coir, but don't have a watering system set up that would incorporate his fertilizer). Locally, my sources are Home Depot (found dolmite lime here), Lowes, and Ace Hardware. Thanks for any advice.

Boca Raton, FL(Zone 10a)

You should be able to find 10-10-10 at one of the three big box stores I would think. That's what Tplant uses in his Earthboxes

Clinton, CT(Zone 6b)

I've used generic 10-10-10, organic 3-4-4 (you need to use more of this), a combination of both and the fertilizer which came with an Earthbox (7-7-7 I think). Didn't notice a difference between any of them except the organic was more expensive.

Carmel, IN(Zone 5b)

I guess what I'm trying to figure out is should it be a granular-type fertilizer? Should I be looking in the lawn care section rather than the flower/plant section? Nothing in the flower/plant section is anything except Miracle Grow (water soluble) or Osmocote. I don't think you're supposed to use either of these in the fertilizer strip, are you?

Boca Raton, FL(Zone 10a)

Look for 40 lb sacks of fertilizer. That's where it will be. Usally on the lower shelves so us old folks can get to it.

Clinton, CT(Zone 6b)

Moms....Habig Garden Shops in Carmel carries Espoma products. Comes in 5lb and 25 lb bags. Garden Tone, Tomato Tone both are fine. Do have to use a cup more than when using non organic fertilizer however.

Places which carry brands such as Espoma often carry generic fertilizer too.

You can find others who carry Espoma products in your area by searching here:


Carmel, IN(Zone 5b)

David_Paul, thank you! I'm familiar with the Espoma brand--now I just have to find the right types. I'll definitely check out Habig's.

Mid-Cape, MA(Zone 7a)

I'm also setting up my EBs with coco coir this year (for the first time.) I have found a source for Espoma 10-10-10 as well as Espoma dolomitic lime. Following Tplants suggestion, I plan to use 2 cups of 10-10-10 and lime. David Paul said:

Do have to use a cup more than when using non organic fertilizer however

So do I use a cup more of both the Espoma fert and the lime?

Clinton, CT(Zone 6b)

Same amount of lime but EarthBox says three cups of organic fert or two of the regular stuff...(EB sells an organic 5-6-6).

When I mixed both, I used one cup of organic and a cup and a half of regular fertilizer. Worked fine.

Do believe there can be a problem with fertilizer mesh size. Earthbox sells a fine grained fertilizer with its boxes.

When I used the larger grained fertilizer commonly available, the plants seemed to lag. Except for one box which had potting mix in it from the year before.

Plants in that box grew fast.

Suspecting the difference was because fertilizer had already leached into the potting mix in that box and was taking time to dissolve in the others, I hit the others with some Miracle Grow dissolved in water. Presto...those plants started to thrive. Never had to use additional Miracle Grow again.

Think this year I''ll find a way to pulverize the 10-10-10 or break it up a little.

Mid-Cape, MA(Zone 7a)

Thanks, David Paul. I have noticed that the Espoma 10-10-10 that I have purchased is relatively large-grained. After your comments, I believe I'll break it up (I've got a mortar and pestle) into smaller pieces. Do you still recommend using 3 cups of organic, even after it's broken up?
Thanks again.

Clinton, CT(Zone 6b)

CapeCod....I would think so. Haven't seen it but I bet Earthbox's organic fertilizer is as finely ground as their regular fertilizer. Here is what EB says in its FAQ:

"Many EarthBox gardeners prefer growing their plants organically. There are several brands of dry granulated organic fertilizer (Plant Right, Fertrell, etc.) that can be used by replacing the 2 cups of chemical fertilizer with 3 cups of organic fertilizer."


Seeing as EB says "The three numbers of the elements making up the fertilizer content should be in the range of 5 to 15" I don't think its all that critical if even more is used of a low numbered organic.

Mid-Cape, MA(Zone 7a)

Thanks, David_Paul, for the clarification about how much dry granulated organic fertilizer to add to my EB.
I went to the helpful link you provided from the EarthBox folks, and read the following:

Most varieties [of tomatoes] require a higher pH level of potting mix. Simply mix one cup of dolomite or hydrated lime to the top 2-3 inches of potting mix (before adding the fertilizer strip) to raise the pH. The EarthBox will do the rest.

Sorry to be such a pest here--but I thought that the optimum amount of lime was 2 cups. Seems like this recommends 1 cup. Or am I misinterpreting the info?

Watertown, WI(Zone 5a)

The EB people recommend more lime than any other source I have ever seen. About 3 years ago I went round and round with their community manager about this.

He couldn't justify the amount of lime they recommend and fell back on 'we have tested and this is what works best'. He then got another job and someone else took over the position so I took the issue up with him and again, he fell back on 'we have tested and...'

At the time they only recommended the lime for tomatos and I pointed out that it is simply false that tomatos require a higher pH than most veggies. They subsequently changed their instructions to lime for all plants.

I am not saying they did this in response to me, simply that they changed their advice/instructions.

They also lowered their recommendation to 1 cup per box instead of 2.

Over the years they have modified their instructions a number of times. The amount of lime to use has gone from 2 cups per box for tomatos to 1 cup per box for all veggies and now back to 2 cups lime, but for all veggies including tomatos.

I have lots of respect for the EB people in terms of the container design, but not for their knowledge of crop nutrition.

One cup of dolomite lime per 2 cubic feet of non limed potting mix based on pine bark or peat moss is good. Some would say this amount is even excessive to the point of being wasteful, others would say it is just right.

You will never need 2 cups per EB (2 cubic feet of mix). Again, this assumes the mix is unlimed to start with, but all commercially bagged mixes based on peat or bark are limed already.

Redding, CA

This message was edited Apr 19, 2009 10:25 AM

Alexandria, VA(Zone 7b)

Right now on hand, I have Espoma PlantTone (5-3-3), GardenTone (4-6-6), TomatoTone (4-7-10). I also picked up some Dynamite Flower & Veg (13-13-13). Which would be best for the EBs- 2 tomatoes each, except for for one w3-4 peppers ?

I also have Espoma Lime & Kelp Meal (no idea what I picked that up for)-should I still add 1 cup of lime to each box? & what about Epsom salts? My mix is coir/ perlite, probably 80/20.

As far as foliar feeding goes, I have Nature's Harvest fish, seaweed, & something for orchids-Greencare MSU form 13-3-15-8ca-2Mg-probably any of these would be good, right?

Clinton, CT(Zone 6b)

Thistle....Dolomitic lime has the magnesium you need. Even some lime which isn't labeled "dolomitic" has enough mg in it. Check the label for magnesium. Adding more in the forum of Epsom Salt could be counterproductive (excess mg can block calcium uptake).

Is the Dynamite 13-13-13 time release? If so you do not want to use that in an Earthbox.

Far as the others, Plant tone is more for foliage growth (high N number) so I would skip that for tomatoes and peppers.

I've used Garden Tone for peppers and squash in an EB and it worked fine. Tomato Tone looks good with that added P in it.

Alexandria, VA(Zone 7b)

D-P, thank you for this info- I'm going to go w/ TomatoTone for most boxes, w/ lime but no epsom salts. GardenTone for the peppers, & I have other containers that this will be used in...I'll put the Dynamite out in all the 'yard veggies', I always have lots of leftover plants that don't make it in containers, but get plopped around the yard....

Watertown, WI(Zone 5a)

For those of you who have had good experiences with tomato tone in the past, keep in mind the formulation for this year has changed. Lower NPK numbers overall and several of the ingredients in the former product are no longer present. This isn't to say the new product is bad, just that you may want to take note of the changed formulation and lower NPK numbers for planning purposes.

West Des Moines, IA(Zone 5a)

I could use some advice as well. My garden center recommended Tomato Tone but they said I should mix it with water first. Is it really ok to just apply it in a strip like the EB website says to? I keep having nightmares of burnt-looking plants!

I bought a big bag of Miracle-Gro potting soil to fill my HEB's with but I'm not sure the N-P-K is right. The garden center guy suggested adding some good aged manure, cotton burrs, and vermiculite to lighten the mix. This is my first year to experiment with container vegetables and as much work as it's been so far to lug the compost up two flights of stairs (I have a third-floor apartment) I want everything to be perfect!

Edit: I forgot to add, the garden center also recommended Nutri-Cal liquid. Should I go back and ask specifically for dolomitic lime? I can just see them coming out of the back room with a 50 lb bag!

This message was edited Apr 27, 2009 12:52 AM

Clinton, CT(Zone 6b)

Tigerlily....you only want potting mix in an self watering container. Water won't wick properly with manure or soil in there.

Mix which already has fertilizer in it, such as some Miracle Grow mixes, is not recomended by Earthbox itself (but I don't think you are going to kill anything. I re-use potting mix and that is saturated with fertilizer from the year before. However you might get a lot of vegatative grow to the detriment of peppers, tomatoes or whatever).

The lime issue is contentious. Earthbox says use it for tomatoes. I've used it for peppers. Others don't see the need as mixes such as ProMix are already pH adjusted and have micronutrients in them.

Not familiar with Nutri-Cal liquid. My general feeling is a lot of stuff (Spray n Grow, foliar sprays, bioactive agents) is unneeded. Some, I'm convinced, have no benefit. Others pop plants up a little but aren't worth the cost. My eggplants, tomatoes and peppers max out their genetic potential without anything special except decomposed manure.

The fertilizer strips in self watering containers work well. Just don't plant anything right up close to them.

Riverdale, NJ(Zone 6a)

Tigerlily... My garden center sells a 20lb bag of dolomitic lime for $3.27. A 20lb bag of the more-expensive pelletized dolomitic lime is $4.99. My pots only need a few cups per year, so either way, it's a pretty good investment. :))


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