Make Your Own Planting Mix (updated 2024)

Note: for all recipes, coir can be substituted for peat moss.

 

The Rodale Instute Mix (organic):

Finely screened compost  4 parts

Peat Moss  2 parts
Perlite  1 part
Vermiculite 1 part

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Another organic mix (from the book, "Rodale Organic Gardening Solutions"):

shredded peat moss  1 bushel
perlite or vermiculite  1 bushel
ground limestone  1/2 cup
bloodmeal  1 cup
colloidal phosphate  1 cup
greensand   1 cup

(1 bushel = 1.24 cubic feet)
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From: Oregon St. University's E-Organic Program

Seedling mixes for starting transplants

Seed mix (Biernbaum, 2001)

• 2 parts screened compost
• 4 parts sphagnum peat
• 1 part perlite
• 1 part vermiculite
• Lime as needed to adjust pH to 6

Seed mix - standard soilless (Biernbaum, 2001)

• 50–75% sphagnum peat
• 25–50% vermiculite
• 5 lbs of ground or superfine dolomitic lime per cubic yard of mix
• Blood meal, rock phosphate, and greensand at 5 to 10 lbs per cubic yard

Organic seedling mix (Biernbaum, 2001)

• 10 gallon of 2 year old leaf mold, sifted
• 10 gallons of sifted compost
• 5–10 gallons of sphagnum peat
• 5 gallons of perlite
• 5 gallons of coarse river sand
• 3 cups blood meal
• 6 cups bone meal

Soilless potting mix (used by Windsor Organic Research on Transition project, E. Zaborski)

• 1 part compost
• 1 part vermiculite
• 1 part peat moss

Screened with ¼ inch screen to mix together. Per 1 gallon mix add:

• 0.6 oz blood meal (17.01 grams)
• 0.4 oz clay phosphate (11.34 grams)
• 0.4 oz greensand (11.34 grams)

Soil-based seedling mix (Hamilton, 1993)

• 2 parts loam (stacked turf to kill any weed seed and disease)
• 2 parts sphagnum peat
• 2 parts coarse grit (sand)
• 30 g or 1 oz lime for each 2 gallon bucket (9 liters)
• 60 g or 1 oz blood meal for each 2 gallon bucket (9 liters)

Organic potting mix (credited to Eliot Coleman in Kuepper, 2004).

• 1 part sphagnum peat
• 1 part peat humus (short fiber)
• 1 part compost
• 1 part sharp sand (builder's)

to every 80 quarts of this add:

• 1 cup greensand
• 1 cup colloidal phosphate
• 1½–2 cups crabmeal or blood meal
• ½ cup lime

Soil block mix (Kuepper, 2004; adapted from Coleman, 1995)

• 3 buckets (standard 10-qt. bucket) brown peat
• ½ cup lime (mix well)
• 2 buckets coarse sand or perlite
• 3 cups base fertilizer (blood meal, colloidal phosphate, and greensand mixed together in equal parts)
• 1 bucket soil
• 2 buckets compost

Seedling mix for soil blocks or seedling flats (from John Greenier of Stoughton, WI in Kuepper, 2004)

• 2 3-gal. buckets Sphagnum peat moss
• ¼ cup lime
• 1½ cups fertility mix (below)
• 1½ buckets vermiculite
• 1½ buckets compost

Fertility mix: 

• 2 cups colloidal (rock) phosphate
• 2 cups greensand
• 2 cups blood meal
• ½ cup bone meal
• ¼ cup kelp meal

Directions for mixing:

1. Add peat to cement mixer or mixing barrel.
2. Spread the lime and fertility mix over the peat.
3. Mix these ingredients thoroughly.
4. Add the compost and vermiculite and mix well again.
5. When done, examine the distribution of vermiculite to ensure that it has been mixed in evenly.

Note that all bulk ingredients should be screened through 1/4 inch hardware cloth. Well matured, manure-based compost should be used (avoid poultry manure and wood-chip bedding).

Mixes for larger plants or containers

These mixes require the addition of mined nutrients from natural sources.

Cornell Organic Substitute for Classic Mix (as modified by Biernbaum, 2001)

• ½ cu yd. sphagnum peat
• ½ cu yd vermiculite
• 5 lbs ground limestone
• 2–4 lbs bone meal
• 5 lbs blood meal

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Check out all the information about potting mixes for Certified Organic Production at the NCAT Sustainable Agriculture Project Website

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Cornell University Modified Peat-Lite Planting Mix:(especially good for seedlings)
for large jobs (1 part=one full wheelbarrow, about 4.5 cu. ft.)
Peat Moss 2 parts
Perlite  1 part
Vermiculite  1 part
Dolomitic Lime (raises pH) 4 cups
Superphosphate (0-20-0) 5 cups
Osmocote or other slow release fertilizer (19-6-12)  8 cups

for small jobs (1 part= a 32 oz. coffee can)
Peat Moss 2 parts
Perlite  1 part
Vermiculite  1 part
Dolomitic Lime (raises pH) 1 tsp.
Superphosphate (0-20-0) 2 tsp.
Osmocote or other slow release fertilizer (19-6-12)  1 Tbs.

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Note: when using peat moss, pre-moisten the peat moss to aid moisture retention. In a hose-end sprayer, put one tablespoon liquid dish detergent in the jar. Set sprayer to mix one tablespoon per gallon of water. Thoroughly water the peat moss with this solution before mixing with other ingredients.

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Purchasing a commercial potting soil or planting mix?

Some tips from the California Master Gardener Handbook:

• Select mixes high in bark, forest materials, or spaghnum peat with vermiculite or perlite.

• Thoroughly leach any potting soil before placing seed or plant material in the mix. Leaching will reduce soluble salts to acceptable levels in most mixes.

•Fertilize with a soluble fertilizer according to manufacturer's directions within two weeks after plants are growing in the new potting/planting mix or potting soil. This will replace leached nutrients and those taken up by the plants.

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The difference between a potting/planting mix and potting soil?

There are no hard and fast rules. Ask 100 experts, you may get 100 different answers. Generally speaking, if the bag says "soil", it probably contains soil and sand, along with ingredients such as perlite, vermiculite, peat moss or bark.

When you buy a garden product with the word "soil" - especially at a low price - you are increasing the chances of buying someone else's problems: a package that contains weed seeds, nematodes, fungal diseases, heavy clay, sludge.

Your best bet, as stated above: choose a product high in forest materials (especially for woody plants), or peat/coir with vermiculite or perlite (for herbaceous or non-woody plants).