Not Enough Mel's Mix?

This year will be my first year trying Square Foot Gardening. I made my Mel's Mix last night. I'm pretty good at math, so I was rather surprised when I didn't have enough Mel's Mix.

I'd like some help from experienced Square Foot Gardeners to figure out where I went wrong and how to fix it.

I made 3 @ 2'x4'x8" boxes and 1 @ 1'x4'x6" riser for a deep box.

3x2x4x.667 = 16 cu ft
1x1x4x.5 = 2 cu ft
Total 18 cu ft

The boards are actually 7.5" and 5.75" or less, so it is really more like 16.9 cu ft.

I used:

1 @ 2 cu ft bag of compost
4 @ 1 cu ft bags of compost
1.5 @ 4 cu ft bag of extra coarse vermiculite
~3 cu ft of compressed peat moss, which should be close to 6 cu ft uncompressed.

That should make 18 cu ft of soil. I should have had about 1 cu ft extra. My boxes are all about 1" short of being full, which means I'm about 2 cu ft short of where I expected to be.

The bags might have contained less than they claimed, but I doubt that. My best guess is that my peat moss volume is wrong.

Was my peat moss not really compressed? It seamed compressed to me, but who really knows.

Was my rough guess that 3 cu ft compressed was 6 cu ft uncompressed wrong?

Did I not uncompress the pet moss enough? There were still some clumps of peat moss.

Most importantly, what do I need to do to fill my boxes the rest of the way? I could add more peat, more compost, or make more Mel's Mix.

Any thought or suggestions on fixing my mix would be greatly appreciated.

Thanks,

Dan

I am so not good with math. I am also very forgetful.

When it came to our making the mix the first time, I spent hours trying to figure it out. I had a 2x4 box and finally I mixed way more than we needed which was really okay as I put lots in pots. First we mixed the blended compost and set it aside. Then we poured out a batch of peat (did all this on a huge tarp) and a batch about the same size of vermiculite, then a batch of blended compost in an amount to look like the same amount as the others. We rolled the tarp to mix the ingredients.

The second batch I made, I mixed x number of buckets of each. I think I got a better balance that way. Both mixes worked just fine.

Making another batch this weekend and will do it the bucket-by-bucket method again. Mixing smaller batches was easier for me and feels like I'm controlling the 1/3 balance better. Did I mention that I'm also a control freak and micro-manager?

My recommendation to you is to mix up another batch being more sure of your individual measurements -- you'll be needing it anyhow for many things including amending your squares as you rotate your crops. Then just add and mix enough of the new mix into the squares to bring the levels up to the height you want.

Finally, I wrote a note in my SFG book on page 101:
--- 2x4 box = 4 cf
--- 4cf / 3 = 1 1/3 cf of each ingredient.

My best to you. Unless you are a control freak like me I would advise -- don't sweat it! Like horseshoes, close is pretty good. And you can amend as needed if you have a supply already made up.

Have fun!

Oh, math problem, fun. (I'm a geek, I know)

[pulls out pen and paper]

Your math is right, and I had similar problems when I started my garden. From my experience there are a few things. First, I don't know that the peat moss doubles in size when uncompressed. Second I think when you mix everything together, it naturally becomes more compact. For example, when you have a bag of extra course vermiculite then there's a lot of air in between the granules. When you mix in the finer compost, it fills in the gaps. Third, I wouldn't be surprised if the bags are a little shy of the exact amount they specify, then again it might be a little more too. Lastly, if the box has gotten watered (either by you or mother nature) that will make it more compact. All together, you'd be surprised how it lowers the level.

There are a couple solutions. First, you can probably just leave it as, especially since you have 8" boxes instead of 6" boxes. Or you could just make more Mel's mix and put it on top.

I found the Square Foot Gardening mix at a local nursery. It was a no-brainer to buy one bag to top off my boxes. Woot!

Dano! What State are you in that you found Mel's Mix? I'd LOVE to find some!!! I'm in North Carolina.

I'm in Missouri. I checked my Lowes and they didn't carry it. I was at a garden center buying seeds and there it was, right at the checkout.

Wow! And you're up north! I'll have to do some more checking around. I'll be thrilled if I can find some around here!

I'm curious, was it the official Mel's Mix brand or their own mix?

I seem to remember seeing some sort of sign at my local nursery about buying Mel's mix, or mix for SFG, but I think they mix it themselves. They also have an area where you can pick up a bag of each part for Mel's mix and it's enough to fill one box.

Kabaju42: It comes bagged and is called Square Foot Gardening Blend. It looks like the cover of the book, but it does not have Mel's name on it. It claims to be officially certified. There was a picture of it on another topic, possibly in the Northern and Central Midwest forum. I'd look for it, but I'm not sure how to post a link to it.

Bec: I've never heard Missouri referred to "up North" before. I guess it is all relative. People up North (Minnesota, Wisconsin, etc) call us down South.

I guess you're right, Dana. You're pretty much central - but you're still a little north of me.