What Went Wrong?

I mixed up my first Mel's Mix today. I had 6 cu ft of vermiculite, 2.2 cu ft very compressed peat moss (which was fluffed before use -would be about 6 cu ft and another bag as backup) and 6 cu ft of blended compost. After reading one bag of compost, I decided against using it since I wasn't sure if it was organic. I figured that when I ran out of peat moss, I'd start fluffing more to match the others. And when I ran out of blended compost, I'd stop and get more. No biggie.

I mixed equal amounts with a bucket into a bigger bucket, then mixed thoroughly and dumped into the raised bed. (The tarp method wouldn't have worked for me.) I ran out of vermiculite first with about 1 cu ft of compost left. (Technically, 2 cu ft because I never ran out to get more.)

I measured by volume and ended up out of whack. I figure that I'll just get more blended compost and peat moss to match and toss that into the bed and stir well. I figure that will fix it, but I'm not sure what caused it. Any ideas? And am I fixing it correctly?

I am bumping this up so more people will see it and give you some more advice.

When I was buying ingredients for my mix, I found it impossible to find bags that used similar measurements on them. Some went by litres..I am in Canada...some went by cubic feet and some went by weight. Go figure. Besides all of that, I totally suck at Math and doing all the conversions from metric to imperial and back again. So I just bought a bunch of stuff and when I was mixing used the same container as a scoop to measure all my ingredients. I did make sure to fluff my peat moss before measuring and I also added the water to it before measuring it into my mix. That makes a difference.

I also do not use the tarp to mix either. For several reasons. I don't have one that DH allows me to put 'dirt' on. And I am just too ( pick one or all....tired, old, lazy, decrepit) to mix that much at once. So I mix it right in the box or in the wheelbarrow and then store it in five gallon pails until I need it.

One thing for sure, if you have too much of anything, let it be compost. Too much peat can cause a crust to form on the top. Also, peat and vermiculite don't have any nutrients for plant to absorb. They are there for water absorption and drainage. So compost is super important. Better to have too much of that and either of the other two.

Hope that helps.

Gwynn

Gwynn

kamavaden wrote:I mixed up my first Mel's Mix today. I had 6 cu ft of vermiculite, peat moss ( 6 cu ft ) and 6 cu ft of blended compost.
I mixed equal amounts with a bucket into a bigger bucket, and dumped into the raised bed.

I didn't see how many boxes/size boxes you were mixing for, but for this you could make roughly 2 4x4 boxes (each box takes roughly 8 cu feet... closer to 9 cubic feet to allow for settling) so that makes 3 cu feet of each ingredient. Okay, assuming the area you're trying to fill is 16 cu feet...

I ran out of vermiculite first with about 1 cu ft of compost left. (Technically, 2 cu ft because I never ran out to get more.)

Many bags of compost either have the weight of the bag, or the cubic feet listed on them... rarely both. I suspect the bags were of the .75 cubic foot variety meaning you would need to have 6 bags per square to equal the amount required. Was it a coarse grade of vermiculite? The Vermiculite is likely the only one close to the true measure. So if you have enough vermiculite to technically fill the required area, I wouldn't concern myself with the perceived underage/overage of the ingredients.

I measured by volume and ended up out of whack. I figure that I'll just get more blended compost and peat moss to match and toss that into the bed and stir well. I figure that will fix it, but I'm not sure what caused it. Any ideas? And am I fixing it correctly?

Of the 3 ingredients, compost is the really important one since it is the only one supplying nutrition for the plant. If the required amount of peat moss is in the bed already (6 cu ft) don't add more as filler. Too much peat is worse than too little. Vermiculite and peat moss in the proper ratio adds a tremendous water retention and aeration ability to the soil. Compost, and the more varieties the better, gives you more vigorous and well balanced plants with more of the trace minerals needed not just the Nitrogen/Phosphorus/Potassium which can be the focus of many fertilizers and people used to traditional row style gardens. Too little of a rich balance of properly composted materials is a genuine hazard of Square Foot Gardening requiring the amendment of other things to make up for it. Err on the side of adding more compost than you need.

Mark

I go by buckets. I just helped with installing beds at our school and the measurements were COMPLETELY out of whack if you went by the package. We went through 46 bags of compost (labeled 1 cf) and ran out even though our vermiculite usage was 24 cu feet. Go by the bucketfull and ignore the bags is my advice. Also, it mixes up "tighter" or more compressed than putting it in separate so in the end, 8 cubic feet of individual ingredients does not equal 8 cubic feet of mix. Does that make sense? So you do need a lot more than you think.
I will have to find my numbers from last week and post them. We filled 10 beds that are 3 1/2 by 3 1/2 and 8 inches tall (we stacked the beds for a total height of 16). In the end we had three beds: two 7 foot by 3 1/2 foot beds and one 3 1/2 foot bed with a height of 16 inches. It cost $350 to fill!!! I had purchased a ton of extra and still need more.

Thank you for your replies. Sorry, but I'm glad I wasn't the only one with this issue. I bought some worm castings and another compost mix today...now, just waiting for the rain to stop. Forecast says 3 or 4 days. It's Oregon.

My bed is 3x15 ft. The depth is not consistent through the entire bed because of the slope of the ground, which drops about 4 inches over the length of the bed but I managed to level it a little more inside the box, so it's probably 8 inches deep on one side, so I estimated 6 cu ft of each. That handy calculator doesn't take that into account. A level bottom would have needed 5.34 cu ft of each. (I just have to be difficult - ask my mom. )

I think maybe the manure & compost was measured packed when it was in the bags with the 1 cu ft label, but I fluffed it up when mixing it, so it had more volume afterward.