Growing Media
Artificial growing media are often called potting mixes. Unlike soils, the performance of a growing media has been engineered to perform in a container for a period. They may contain materials such as composted pine bark, peat, coir fibre, sawdust, compost, sand, polystyrene, perlite, vermiculite, zeolite, wetting agents and fertiliser.
Seed Raising Mixes
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Nancy Bubel (The New Seed-Starters Handbook) lists the following characteristic of quality growing media:
Free from competing weed seeds, soilborne diseases, and fungus spores
Able to absorb and hold quantities of moisture
Able to drain quickly, leaving necessary air between moist particles
Fine textured
Organic and sustainable
Non-crusting
At MVCG, we use a premium commercial seed-raising mix and mixes we make on site.
Commercial mixes
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There is a great deal of variation with off-the-shelf mixes, and it is advised to try a few premium brands, side-by-side until you find the quality you are after.
For vegetable seedlings, we add two to three cups of a slow-release, organic fertiliser pellet (check the label for application rates). We do this in a wheelbarrow so that the fertiliser is properly distributed through the growing media.
MVCG seed-raising mix
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It is a mixture of vermiculite, compost and coir. We also add slow-release fertiliser for vegetable seedlings. We mix this in a wheelbarrow, usually with a 9L bucket as the ‘measurer’
2 parts vermiculite,
2 parts coir
3 parts compost
Three to four cups of a slow-release, pelleted fertiliser is added along with a cup of blood-and-bone. This is mixed very well to break up the coir and evenly distribute the components.
MVCG potting mix with the lot
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This is our bulk mix with the main ingredient being used or recycled potting mix. These are less precise measurements.
A ‘wheelbarrow’ (about four 9L buckets) of old potting mix.
Two shovels of coir
Two shovels of compost
Two shovels of coffee grounds
Two cups of blood-and-bone
A handful of dolomite lime
Mix well to distribute the components.
