Hi Helen –
No, you will not need to add any top soil into the Mel’s Mix.
According to Square Foot Gardening’s website (founded by Mel Bartholomew), the growing media mixture contains the following:
1/3 Vermiculite
1/3 Peat Moss
1/3 Compost from:
– Chicken manure
– Leaf & wood mulch
– Algae
– Garden & kitchen scraps
– Other
Many growing mediums or “potting soils” do not actually contain any soil, but rather a mixture of various other soilless media and fertilizers.
However, when you do mix up this particular recipe, you will also need to incorporate a manure based compost in addition to the leaf compost. Each type of manure will play a different role, so it is important to have both. Just be sure that they still only make up one-third of the mixture.
Manure based compost contains loads of beneficial bacteria and micro-nutrients. It is very high in nitrogen and will aid in water retention.
Leaf based compost will help to improve the structure of your medium by adding drainage and aeration. Additionally, it is highly mineral rich – containing many trace elements.
With the addition of manure compost, you should have all of the elements to create a great growing media mix!
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