Blending of Mel's Mix & Screwing up "1/3" Formula

Good afternoon all, 
Creating separate Topic to see if I can get some responses:   

1.  Are there, or could there be,  any issues with the top 6" of Mel's Mix blending in with whatever we choose to put under the MM (topsoil in our case)  and screwing up the 1/3, 1/3, 1/3 formula?  

2.  The S.F. Gardening  book, 3rd edition, recommends putting compost back  into divot created by the   harvested veggies ... How does one know how much compost has to be added back to keep the formula at 1/3 compost ?  

Fishtell

1. No, not an issue.  I have built raised beds with various things to fill the first foot or so, and never had an issue. Some of the beds are filled with the Hugelkultur method, using tree limbs, wood chips, etc., and MM on top (I put straw on top of the wood to provide a solid base for the soil). Some of the beds are filled using top soil for the first foot, or so, and then MM on top (these have been the least productive due to the top soil not providing good drainage). A couple of the beds were filled using bulk compost from the county recycle center for the first foot, and then MM on top (I did this because the county compost was poor quality, not to be used for the vegetables).  All of these methods have worked, and over time the earthworms, etc., will enrich the base soil to make it more fertile.

2. After the initial fill with MM, don't worry about maintaining the 1/3rd compost ratio. Of the years, most of my beds are almost pure compost. Every 4 or 5 years, I may work some vermiculite and/or coir into the soil to loosen it and help with water retention, but the plants will grow beautifully in the compost. When you remove plants (Note: I do not remove plants, I simply cut them off at soil level and let the roots decompose in the soil), add some fresh compost to refresh the bed before replanting.

OhioGardener wrote: When you remove plants (Note: I do not remove plants, I simply cut them off at soil level and let the roots decompose in the soil), add some fresh compost to refresh the bed before replanting.

Interesting.  Do the roots decompose over the winter?   Even for tomato plants?  If so, i may have to try that.

Yes, they decompose rapidly due to all of the microbial life and earthworms in the soil. And, they add carbon to the soil as they decompose. When planting in the spring, I have never found roots from the previous season.

Fishtell, Welcome to the Forum from central CA.

1. The bottom fill of a deep bed can be sand or decent draining dirt. Or, what ever.

2. The amount of blended compost to put in the divot, or in the whole bed, is the amount needed to bring the level of the MM back up to the original height.

To pull up the whole plant, or cut it off just under the soil line, is a personal decision. Being in CA, my beds are in constant use year around, so I have to pull the plants so I can put in the next season plants. I leave smaller roots that don't interfere with planting, since they will eventually decompose. OG lives in a different Zone, so he can easily leave the under-root system in place.