All good potting mixes should:
1) Provide water and air.
***** Potting mixes are made of both solid particles and the open spaces (pores) between them. Large pores are filled with air and small pores hold water.* A good potting mix should have a balance of both solid particles and large and small pore space. Potting mixes with too many large pores require frequent watering, but those with too many small pores are too heavy and can promote disease. It is important to handle a potting mix carefully once it is made to avoid compacting it and losing the air spaces.
2) Retain fertilizer.
***** Potting mixes made mostly from sand will have little ability to hold plant food, while mixes formed from lots of peat moss or compost will hold plant food well. The pH of the mix also affects nutrient availability. Peat moss, which is the most commonly used ingredient in potting mixes, is very acidic (low pH). Dolomitic limestone is often added to adjust the pH and bring it closer to neutral. Compost and sand are usually neutral (depending on what they are made from) and may require less limestone when they are used in potting mixes.
3) Support the plant.
4) Be of consistent quality.
Organic Potting Mixes
The production of certified organic vegetable transplants is dependent on an organic potting mix. Potting soils containing prohibited materials will not be allowed under the proposed rules of the National Organic Program. Synthetic chemical fertilizers and wetting agents--amendments commonly used in commercial mixes--are restricted in most programs and therefore alternative mixes are needed.
Purchasing a commercially prepared organic mix is the easiest way to get started. Organic mixes are available from a few dealers around the country. Unless a mix specifically states that it is organic, it probably contains prohibited ingredients. A partial listing of suppliers is included in the table below. A second option is to arrange a special order from one of the large commercial potting mix suppliers, whereby they agree to exclude starter fertilizers and wetting agents. A third option is to mix your own. As freight is often prohibitive in the first two cases, many growers prefer the last method, but this presents a new set of challenges. For recipes of potting mixes, see Appendix C.
There are no industry-wide standards concerning potting media, so the grower should be wary of buying bagged materials with which he or she is not familiar. Bags labeled as compost, for example, may contain inorganic materials, depending on where the compost came from and what composes it.
Types of Potting Mixes
The types and amounts of potting mix ingredients should change depending on the intended use. Mixes used to start seeds must be very light and full of air because seedlings die easily in heavy, wet soil. Plants grown in fairly small plug trays need a soil mix that is lighter than one used in a larger plug trays. In general, the younger and smaller the plant, the lighter the soil mix needs to be. Soil mixes that are used after the seeds are started usually contain some perlite or sand, as well as peat.
Description of Standard Potting Mix Ingredients
Sphagnum peat moss. Also called peat moss or simply peat. Peat moss is a very stable source of organic material that holds a great deal of water and air and does not decompose quickly. Peat moss is quite acidic (pH 3.5-4.0); limestone is added to the mix to balance the pH. Younger, lighter colored peat moss does a better job of providing air space than does older, darker peats that have few large pores for air space. A wide range of quality exists. Peat is the most widely used soilless medium, because of its wide availability and relatively low cost.
Composted pine bark. Its high lignin content makes it slow to degrade, so it nourishes beneficial organisms for months. Can be substituted in part for peat moss. Lightens the mix.
Sawdust. Similar to peat moss in most ways. Quality depends on type of tree: cedar, walnut, and redwood can be toxic to plants, and oak, hickory and maple deplete soil nitrogen more so than sawdust from evergreen needle trees.
Vermiculite: Handled gently, vermiculite provides plenty of air spaces in a mix. Handled roughly, vermiculite compacts and loses its ability to hold air. Vermiculite holds water and fertilizer in the potting mix. It also contains calcium and magnesium, and has a near-neutral pH. Vermiculite comes in different grades. Medium grade is usually used for starting seeds. A coarse grade can be used in soil mix for older plants.
Perlite: Perlite is a volcanic rock that has been heated and expanded to become a lightweight, white material. Perlite is sterile and pH-neutral. When added to a soil mix, perlite can improve air space and water drainage. It is a hard material that does not break apart easily. Perlite pieces create tiny air tunnels, that allow water and air to flow freely to the roots. Perlite will hold from 3 to 4 times its weight in water, yet will not become soggy. Perlite can be used instead of sand to reduce the soil mix weight. It holds very little water and costs are relatively high. It is much lighter than sand and can be used instead of it.
Limestone: Calcium carbonate (CaC03) or calcium magnesium carbonate (called dolomitic limestone) is used to adjust pH. The range can be adjusted for specific crops, but a pH range of 5.5 to 6 is ideal for most crops. Lime should be well-ground.
Sand: Coarse sand (sometimes called builder s sand) will add air space to the potting mix. Fine sand settles into the spaces between other ingredients and makes a dense mix that excludes air. Clean, washed sand has a near-neutral pH and little if any food value for plants. Sand is much heavier than any other ingredient used in potting mixes. The added weight is good for tall, top-heavy plants that might blow or tip over, but it is not the best choice for plants that will be shipped or moved a lot. Sand is the least expensive and most readily available source of larger-particle material.
Commercial Starter Fertilizer: Most commercial mixes contain starter fertilizer blends. Whether the blends are made of micro- or macro-nutrients, they are usually formed from synthetic fertilizer. These fertilizers are prohibited from use in potting media used for certified organic production.
Wetting Agents: Wetting agents are a common ingredient in commercial potting mixes. They are included to help regulate moisture, improve aeration, and increase nutrient availability. Most wetting agents do not qualify for approval by organic certifying agencies. Check with a local certifying agent to see if there are any approved materials with wetting properties. Safers Soap® products have surfactant qualities and might be suitable. Some certifying agencies also accept Shaklee s Basic-H® and similar materials considered to be biodegradable. Wetting agents should be used conservatively. Some commercial materials have been found to be deleterious at too high a concentration (1). A University of California Peat-Lite mix employs 3 oz. of wetting agent for a 17 cubic foot media mix consisting of equal portions of peat moss and vermiculite(2). The wetting qualities of compost-based mixes may be superior to peat-based mixtures and may not need wetting agents.
Description of Alternative Potting Mix Ingredients
Compost: Made from a variety of locally available materials, usually a combination of ingredients that are high in nitrogen (such as manure or alfalfa) and those high in carbon (such as straw or corn stocks). Compost holds water well and provides nutrients; the amount of nutrients provided depends on what it is made from. It is important to select the highest quality compost available. It can be used with or in place of peat moss. Compost is cheaper than peat moss and contains nutrients. Compost can also provide natural protection against diseases of the seedlings and roots of plants due to beneficial organisms that live in well-made compost. For more information on disease-suppressive composts, contact ATTRA.
Alfalfa: Alfalfa may be a good, locally available, alternative to peat moss. Alfalfa provides nutrients, especially nitrogen, that releases slowly in the mix, making the fertilizer less likely to flow out of the pot when irrigated. Raw alfalfa must be processed before use in a potting mix. To process: Grind raw alfalfa through a 2 cm screen. Add water and decompose for 20 days. Air dry for another 20 days after decomposition.
Newspaper: Ground-up newspapers might be a good ingredient in a potting mix, and could be used instead of peat moss. Newsprint should not be more than 25% by volume of the mix.
Coir: Coir comes from coconut husks and is a waste product of the coco fiber industry. Coir s structure is similar to that of peat, but its pH is higher (5.5-6.0). It holds up to nine times its weight in water. Coir can have a high salt content. See below for coir suppliers.
Mineral wool: This is a coarse material resembling fiberglass, spun from blast furnace slag. Very little research has been done with mineral wool. It might be a sustainable option for growers near factories that produce blast furnace slag.
Kenaf: Kenaf is a fibrous plant grown in the Deep South. At the end of the growing season, kenaf plants are cut down and parts of them used to make paper. The waste products can be used as growing media. Growers who have used kenaf have seen excellent results.
Potting Mixes
List below is sorted as:
Product
Supplier*
Contents
pH
ASB Greenworld
Canadian sphagnum peat moss, vermiculite, perlite, montmorillonite clay, starter fertilizer, trace minerals
*
Baccto Seedling & Propagating Mix
Michigan Peat Co.*
Horticultural sphagnum, perlite, vermiculite, lime, balanced nutrients, trace elements, wetting agent
5.9-6.2
Ball Peat Lite Mix*
Ball Seed Co.*
Canadian sphagnum peat moss, vermiculite, wetting agent, nutrients*
*
Ball Professional Plug & Seedling Mix*
Ball Seed Co.*
Canadian sphagnum peat moss, vermiculite, perlite, builders' sand, wetting agent, nutrients*
*
BC-2
Bio Comp
Sphagnum peat moss, composted pine bark, vermiculite
5.6-6.4
BC-4FP
Bio Comp
Sphagnum peat moss, composted pine bark, composted peanut hulls, vermiculite, perlite, dolomitic limestone, gypsum, starter fertilizer
5.6-6.4
BC-H4
Bio Comp
Sphagnum peat moss, composted pine bark, composted peanut hulls, dolomitic limestone, gypsum, starter fertilizer
5.6-6.4
BM2 Germinating Mix
Berger Peat Moss
Fine granulation peat moss, perlite, vermiculite, lime, wetting agent, nutrients
*
Burpee Seed-Starting Formula
Burpee*
Canadian sphagnum peat moss, vermiculite, wetting agent, dolomite limestone, gypsum & other minerals
5.5-5.7
Control Gro
Hyde Park
Sphagnum peat moss, perlite, vermiculite, wetting agent, starter fertilizer, nutrients*
*
Earth-Rite Potting Soil
Zook & Ranck
Composted manures, peat moss, seaweed, colloidal phosphate
6.5-7.0
Fafard's Germinating (Superfine) Mix
Conrad Fafard
Peat moss, fine perlite, vermiculite, wetting agent, starter fertilizer
5.5-6.5
Fafard's All Purpose Growing Mix
Conrad Fafard
Perlite, vermiculite, sphagnum peat moss, wetting agent, calcium nitrate, potassium nitrate, phosphoric acid and other minerals
5.5-6.5
Fertilmix
A.H. Hoffman, Inc.
Sphagnum peat moss, vermiculite, limestone, ammonium nitrate, super phosphate
5.6-5.9
Garden Magic Potting Soil
Michigan Peat Co.
Peat moss, perlite, starter fertilizer
6.0-6.5
Gardner & Bloome Acid Planting Mix
Harmony Farm Supply
Fir bark, forest humus, peat moss, worm castings, sand
*
Gardner & Bloome Organic Potting Soil
Harmony Farm Supply
Fir bark, worm castings, topsoil, redwood, peat moss, perlite, chicken manure
*
Gardner & Bloome Organic Soil Building Compost
Harmony Farm Supply
Forest humus, worm castings, chicken manure, bat guano, kelp meal, oystershell, dolomitic limestone
*
Gardner & Bloome Planting Mix
Harmony Farm Supply
Forest humus, fir bark, peat moss, chicken manure, top soil, worm castings, sand, oyster shell lime
*
Good Earth Organics Mix
Good Earth Organics
Peat, perlite, vermiculite
*
Greendell Farm Plug Mix
Greendell Farm
Sphagnum peat moss, perlite, vermiculite, composted bark, starter fertilizer, wetting agent
5.6-5.9
Greenway Seedling Mix
Blackmore Co.
Peat, vermiculite, perlite, wetting agent
*
Heco Plug Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), vermiculite, perlite, wetting agent, minor elements, ammonia-free fertilizer
*
Heco Seedling Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), wetting agent, minor elements, ammonia-free fertilizer
*
Heco Tomato Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), perlite, wetting agent, minor elements
*
Hyponex Professional Mix
Scotts Corp.
Sphagnum peat moss, vermiculite, perlite, peat humus, pine bark, wetting agent
5.3-6.8
Jiffy Mix
Jiffy
Canadian sphagnum peat moss, vermiculite, lime, wetting agent, macro- & micronutrients*
5.0-5.8
Jiffy Mix Plus
Jiffy
Canadian sphagnum peat moss, vermiculite, lime, wetting agent, macro- & micronutrients, Mag Amp
5.0-5.8
McEnroe Organic Mix
McEnroe Organic Farm Assoc.
Custom potting soil made from compost
*
MetroMix 350, 360, 365, plug mixes
Grace-Sierra
Peat moss, vermiculite, bark, ash, wetting agent, starter fertilizer
5.0-6.4
MetroMix 351, 135P
Grace Sierra
Peat moss, vermiculite, perlite, bark ash, composted pine bark, wetting agent, starter fertilizer
5.0-6.4
Nature's Way Potting Soil
Nature's Way
Coarse peat moss, sand, perlite, rock phosphate, greensand, dolomite limestone, charcoal, kelp, cottonseed meal, fish emulsion
6.5-7.0
New Era Potting Soil
Clinton Nursery Products
Peat humus, Canadian sphagnum peat moss, vermiculite, coarse sand, dolomitic limestone
6.0-6.5
Johnny's Selected Seeds
Screened sphagnum peat moss, sedge, black peat, compost, perlite, and triple superphosphate
*
Pargro Peatwool Fine
Pargro
Peat moss, Pargro granulated rockwool, wetting agent, lime, starter fertilizer
5.4-6.2
Paygro Natural Potting Soil
Paygro Co.
Composted hardwood bark, sand, sphagnum peat moss, reed sedge peat
6.5-7.0
Peter's Professional Potting Soil
Grace- Sierra
Canadian sphagnum peat moss, vermiculite, granite sand, bark ash, nitrogen, phosphorus, potassium, calcium and other minerals, wetting agent
5.8-6.8
Pro Mix PGX
Premier Sales
Sphagnum peat moss (fine), vermiculite (fine), wetting agent, macro- & micronutrients, dolomitic and calcitic limestone
5.5-6.2
Quick-Root Soilless Potting Mix
Peaceful Valley
Canadian sphagnum peat moss, vermiculite, compost, oystershell lime, gypsum, soft rock phosphate, bone meal, sulfate of potash, kelp meal
*
Redi-Earth Potting Soil
Grace-Sierra
Canadian sphagnum peat moss, vermiculite, nitrogen, phosphorus, potassium, calcium and other minerals, wetting agent
5.2-6.3
Sogemix Plug & Germinating Mix
Sogevex
Sphagnum peat moss (fine), vermiculite (fine), wetting agent, macro- & micronutrients, dolomitic and calcitic limestone
5.5-6.2
SI-6 Seedling & Germinating Mix*
Southern Importers
Composted pine bark, composted peanut hulls, Canadian sphagnum peat moss, vermiculite, perlite, wetting agent, gypsum, starter fertilizer, dolomitic limestone
5.8-6.2
Strong-Lite Bedding Plant Mix
Strong-Lite
1/4" fully composted pine bark, medium vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
*
Strong-Lite Germination Mix
Strong-Lite
Medium vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
*
Strong-Lite Vegetable Mix
Strong-Lite
Coarse vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
*
Sunshine #3
Sun Gro*
Sphagnum peat, vermiculite, starter fertilizer, wetting agent, dolomitic limestone
*
Sunshine #4 and #5
Sun Gro
Sphagnum peat, fine perlite, starter fertilizer, wetting agent, dolomitic limestone
*
Terra-lite Perlite Plug Mix
Grace-Sierra
Peat moss, vermiculite, perlite, wetting agent, starter fertilizer
5.3-6.3
Terra-lite Plug Mix
Grace-Sierra
Peat moss, vermiculite, wetting agent, starter fertilizer
5.3-6.5
Low pH mix 4.8-5.9
Uncle Malcolm's Organic Planting Mix
Peaceful Valley
Canadian peat moss, composted fir, sterilized mushroom compost (composted straw, sphagnum moss, horse and chicken manures, cottonseed and soybean meals, gypsum, sulfur), compost (dried poultry waste, bonemeal, bloodmeal, feather meal, dolomitic limestone)
*
Uncle Malcolm's Organic Potting Mix
Peaceful Valley
Sphagnum peat moss, perlite, volcanic pumice, earthworm castings
*
V-Mix
Lambert Peat Moss
Peat moss, perlite, vermiculite, limestone, nutrients, trace elements, wetting agent
*
*
*
Recipes for Starting Seeds
Mixes for starting seeds must be very light and provide a lot of air space to prevent root diseases. Seedling soil mixes may or may not contain nutrients because seedlings are often transplanted very quickly after germination.
Seed mix #1:
5 parts compost (well rotted)
4 parts topsoil (loam)
1-2 parts sharp sand
1-2 parts leaf mold
1 part sphagnum peat moss
2 tablespoons lime
Seed mix #2:
2 parts sifted compost
4 parts sphagnum peat moss
1 part perlite
1 part vermiculite
4 oz. lime
Seed mix #3: Standard soilless seed starting mix
50 to 75 percent sphagnum peat moss
25 to 50 percent vermiculite
5 lbs. of ground limestone per cubic yard of mix
*
Organic seedling mix:
6 gallons sphagnum peat moss
1/4 cup lime
4.5 gallons vermiculite
4.5 gallons compost
1 1/2 cups fertility mix made of:
2 cups colloidal (rock) phosphate
2 cups greensand
1/2 cup bone meal
1/4 cup kelp meal
Organic seedling mix:
10 gallons of 2-year-old leaf mold, sifted
10 gallons sifted compost
5-10 gallons sphagnum peat moss
5 gallons perlite
5 gallons coarse river sand
2 cups blood meal
6 cups bone meal
*
Mixes for potted plants require the addition of nutrients either from natural forms such as bloodmeal, bonemeal or rock phosphate, or from synthetic fertilizers such as calcium nitrate or potassium superphosphate. Locally available sources of nitrogen might be animal manures, fish products, dried blood, and legumes such as alfalfa or clover. Phosphorus can be supplied by bonemeal or rock phosphate. Wood ashes contain 10% potassium. Vermiculite also contains some potassium.
*
*
SEE MIXES ON NEXT POST
1) Provide water and air.
***** Potting mixes are made of both solid particles and the open spaces (pores) between them. Large pores are filled with air and small pores hold water.* A good potting mix should have a balance of both solid particles and large and small pore space. Potting mixes with too many large pores require frequent watering, but those with too many small pores are too heavy and can promote disease. It is important to handle a potting mix carefully once it is made to avoid compacting it and losing the air spaces.
2) Retain fertilizer.
***** Potting mixes made mostly from sand will have little ability to hold plant food, while mixes formed from lots of peat moss or compost will hold plant food well. The pH of the mix also affects nutrient availability. Peat moss, which is the most commonly used ingredient in potting mixes, is very acidic (low pH). Dolomitic limestone is often added to adjust the pH and bring it closer to neutral. Compost and sand are usually neutral (depending on what they are made from) and may require less limestone when they are used in potting mixes.
3) Support the plant.
4) Be of consistent quality.
Organic Potting Mixes
The production of certified organic vegetable transplants is dependent on an organic potting mix. Potting soils containing prohibited materials will not be allowed under the proposed rules of the National Organic Program. Synthetic chemical fertilizers and wetting agents--amendments commonly used in commercial mixes--are restricted in most programs and therefore alternative mixes are needed.
Purchasing a commercially prepared organic mix is the easiest way to get started. Organic mixes are available from a few dealers around the country. Unless a mix specifically states that it is organic, it probably contains prohibited ingredients. A partial listing of suppliers is included in the table below. A second option is to arrange a special order from one of the large commercial potting mix suppliers, whereby they agree to exclude starter fertilizers and wetting agents. A third option is to mix your own. As freight is often prohibitive in the first two cases, many growers prefer the last method, but this presents a new set of challenges. For recipes of potting mixes, see Appendix C.
There are no industry-wide standards concerning potting media, so the grower should be wary of buying bagged materials with which he or she is not familiar. Bags labeled as compost, for example, may contain inorganic materials, depending on where the compost came from and what composes it.
Types of Potting Mixes
The types and amounts of potting mix ingredients should change depending on the intended use. Mixes used to start seeds must be very light and full of air because seedlings die easily in heavy, wet soil. Plants grown in fairly small plug trays need a soil mix that is lighter than one used in a larger plug trays. In general, the younger and smaller the plant, the lighter the soil mix needs to be. Soil mixes that are used after the seeds are started usually contain some perlite or sand, as well as peat.
Description of Standard Potting Mix Ingredients
Sphagnum peat moss. Also called peat moss or simply peat. Peat moss is a very stable source of organic material that holds a great deal of water and air and does not decompose quickly. Peat moss is quite acidic (pH 3.5-4.0); limestone is added to the mix to balance the pH. Younger, lighter colored peat moss does a better job of providing air space than does older, darker peats that have few large pores for air space. A wide range of quality exists. Peat is the most widely used soilless medium, because of its wide availability and relatively low cost.
Composted pine bark. Its high lignin content makes it slow to degrade, so it nourishes beneficial organisms for months. Can be substituted in part for peat moss. Lightens the mix.
Sawdust. Similar to peat moss in most ways. Quality depends on type of tree: cedar, walnut, and redwood can be toxic to plants, and oak, hickory and maple deplete soil nitrogen more so than sawdust from evergreen needle trees.
Vermiculite: Handled gently, vermiculite provides plenty of air spaces in a mix. Handled roughly, vermiculite compacts and loses its ability to hold air. Vermiculite holds water and fertilizer in the potting mix. It also contains calcium and magnesium, and has a near-neutral pH. Vermiculite comes in different grades. Medium grade is usually used for starting seeds. A coarse grade can be used in soil mix for older plants.
Perlite: Perlite is a volcanic rock that has been heated and expanded to become a lightweight, white material. Perlite is sterile and pH-neutral. When added to a soil mix, perlite can improve air space and water drainage. It is a hard material that does not break apart easily. Perlite pieces create tiny air tunnels, that allow water and air to flow freely to the roots. Perlite will hold from 3 to 4 times its weight in water, yet will not become soggy. Perlite can be used instead of sand to reduce the soil mix weight. It holds very little water and costs are relatively high. It is much lighter than sand and can be used instead of it.
Limestone: Calcium carbonate (CaC03) or calcium magnesium carbonate (called dolomitic limestone) is used to adjust pH. The range can be adjusted for specific crops, but a pH range of 5.5 to 6 is ideal for most crops. Lime should be well-ground.
Sand: Coarse sand (sometimes called builder s sand) will add air space to the potting mix. Fine sand settles into the spaces between other ingredients and makes a dense mix that excludes air. Clean, washed sand has a near-neutral pH and little if any food value for plants. Sand is much heavier than any other ingredient used in potting mixes. The added weight is good for tall, top-heavy plants that might blow or tip over, but it is not the best choice for plants that will be shipped or moved a lot. Sand is the least expensive and most readily available source of larger-particle material.
Commercial Starter Fertilizer: Most commercial mixes contain starter fertilizer blends. Whether the blends are made of micro- or macro-nutrients, they are usually formed from synthetic fertilizer. These fertilizers are prohibited from use in potting media used for certified organic production.
Wetting Agents: Wetting agents are a common ingredient in commercial potting mixes. They are included to help regulate moisture, improve aeration, and increase nutrient availability. Most wetting agents do not qualify for approval by organic certifying agencies. Check with a local certifying agent to see if there are any approved materials with wetting properties. Safers Soap® products have surfactant qualities and might be suitable. Some certifying agencies also accept Shaklee s Basic-H® and similar materials considered to be biodegradable. Wetting agents should be used conservatively. Some commercial materials have been found to be deleterious at too high a concentration (1). A University of California Peat-Lite mix employs 3 oz. of wetting agent for a 17 cubic foot media mix consisting of equal portions of peat moss and vermiculite(2). The wetting qualities of compost-based mixes may be superior to peat-based mixtures and may not need wetting agents.
Description of Alternative Potting Mix Ingredients
Compost: Made from a variety of locally available materials, usually a combination of ingredients that are high in nitrogen (such as manure or alfalfa) and those high in carbon (such as straw or corn stocks). Compost holds water well and provides nutrients; the amount of nutrients provided depends on what it is made from. It is important to select the highest quality compost available. It can be used with or in place of peat moss. Compost is cheaper than peat moss and contains nutrients. Compost can also provide natural protection against diseases of the seedlings and roots of plants due to beneficial organisms that live in well-made compost. For more information on disease-suppressive composts, contact ATTRA.
Alfalfa: Alfalfa may be a good, locally available, alternative to peat moss. Alfalfa provides nutrients, especially nitrogen, that releases slowly in the mix, making the fertilizer less likely to flow out of the pot when irrigated. Raw alfalfa must be processed before use in a potting mix. To process: Grind raw alfalfa through a 2 cm screen. Add water and decompose for 20 days. Air dry for another 20 days after decomposition.
Newspaper: Ground-up newspapers might be a good ingredient in a potting mix, and could be used instead of peat moss. Newsprint should not be more than 25% by volume of the mix.
Coir: Coir comes from coconut husks and is a waste product of the coco fiber industry. Coir s structure is similar to that of peat, but its pH is higher (5.5-6.0). It holds up to nine times its weight in water. Coir can have a high salt content. See below for coir suppliers.
Mineral wool: This is a coarse material resembling fiberglass, spun from blast furnace slag. Very little research has been done with mineral wool. It might be a sustainable option for growers near factories that produce blast furnace slag.
Kenaf: Kenaf is a fibrous plant grown in the Deep South. At the end of the growing season, kenaf plants are cut down and parts of them used to make paper. The waste products can be used as growing media. Growers who have used kenaf have seen excellent results.
Potting Mixes
List below is sorted as:
Product
Supplier*
Contents
pH
ASB Greenworld
Canadian sphagnum peat moss, vermiculite, perlite, montmorillonite clay, starter fertilizer, trace minerals
*
Baccto Seedling & Propagating Mix
Michigan Peat Co.*
Horticultural sphagnum, perlite, vermiculite, lime, balanced nutrients, trace elements, wetting agent
5.9-6.2
Ball Peat Lite Mix*
Ball Seed Co.*
Canadian sphagnum peat moss, vermiculite, wetting agent, nutrients*
*
Ball Professional Plug & Seedling Mix*
Ball Seed Co.*
Canadian sphagnum peat moss, vermiculite, perlite, builders' sand, wetting agent, nutrients*
*
BC-2
Bio Comp
Sphagnum peat moss, composted pine bark, vermiculite
5.6-6.4
BC-4FP
Bio Comp
Sphagnum peat moss, composted pine bark, composted peanut hulls, vermiculite, perlite, dolomitic limestone, gypsum, starter fertilizer
5.6-6.4
BC-H4
Bio Comp
Sphagnum peat moss, composted pine bark, composted peanut hulls, dolomitic limestone, gypsum, starter fertilizer
5.6-6.4
BM2 Germinating Mix
Berger Peat Moss
Fine granulation peat moss, perlite, vermiculite, lime, wetting agent, nutrients
*
Burpee Seed-Starting Formula
Burpee*
Canadian sphagnum peat moss, vermiculite, wetting agent, dolomite limestone, gypsum & other minerals
5.5-5.7
Control Gro
Hyde Park
Sphagnum peat moss, perlite, vermiculite, wetting agent, starter fertilizer, nutrients*
*
Earth-Rite Potting Soil
Zook & Ranck
Composted manures, peat moss, seaweed, colloidal phosphate
6.5-7.0
Fafard's Germinating (Superfine) Mix
Conrad Fafard
Peat moss, fine perlite, vermiculite, wetting agent, starter fertilizer
5.5-6.5
Fafard's All Purpose Growing Mix
Conrad Fafard
Perlite, vermiculite, sphagnum peat moss, wetting agent, calcium nitrate, potassium nitrate, phosphoric acid and other minerals
5.5-6.5
Fertilmix
A.H. Hoffman, Inc.
Sphagnum peat moss, vermiculite, limestone, ammonium nitrate, super phosphate
5.6-5.9
Garden Magic Potting Soil
Michigan Peat Co.
Peat moss, perlite, starter fertilizer
6.0-6.5
Gardner & Bloome Acid Planting Mix
Harmony Farm Supply
Fir bark, forest humus, peat moss, worm castings, sand
*
Gardner & Bloome Organic Potting Soil
Harmony Farm Supply
Fir bark, worm castings, topsoil, redwood, peat moss, perlite, chicken manure
*
Gardner & Bloome Organic Soil Building Compost
Harmony Farm Supply
Forest humus, worm castings, chicken manure, bat guano, kelp meal, oystershell, dolomitic limestone
*
Gardner & Bloome Planting Mix
Harmony Farm Supply
Forest humus, fir bark, peat moss, chicken manure, top soil, worm castings, sand, oyster shell lime
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Good Earth Organics Mix
Good Earth Organics
Peat, perlite, vermiculite
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Greendell Farm Plug Mix
Greendell Farm
Sphagnum peat moss, perlite, vermiculite, composted bark, starter fertilizer, wetting agent
5.6-5.9
Greenway Seedling Mix
Blackmore Co.
Peat, vermiculite, perlite, wetting agent
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Heco Plug Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), vermiculite, perlite, wetting agent, minor elements, ammonia-free fertilizer
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Heco Seedling Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), wetting agent, minor elements, ammonia-free fertilizer
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Heco Tomato Mix
J-M Trading
Brick-cut Canadian sphagnum peat moss (fine-screened), perlite, wetting agent, minor elements
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Hyponex Professional Mix
Scotts Corp.
Sphagnum peat moss, vermiculite, perlite, peat humus, pine bark, wetting agent
5.3-6.8
Jiffy Mix
Jiffy
Canadian sphagnum peat moss, vermiculite, lime, wetting agent, macro- & micronutrients*
5.0-5.8
Jiffy Mix Plus
Jiffy
Canadian sphagnum peat moss, vermiculite, lime, wetting agent, macro- & micronutrients, Mag Amp
5.0-5.8
McEnroe Organic Mix
McEnroe Organic Farm Assoc.
Custom potting soil made from compost
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MetroMix 350, 360, 365, plug mixes
Grace-Sierra
Peat moss, vermiculite, bark, ash, wetting agent, starter fertilizer
5.0-6.4
MetroMix 351, 135P
Grace Sierra
Peat moss, vermiculite, perlite, bark ash, composted pine bark, wetting agent, starter fertilizer
5.0-6.4
Nature's Way Potting Soil
Nature's Way
Coarse peat moss, sand, perlite, rock phosphate, greensand, dolomite limestone, charcoal, kelp, cottonseed meal, fish emulsion
6.5-7.0
New Era Potting Soil
Clinton Nursery Products
Peat humus, Canadian sphagnum peat moss, vermiculite, coarse sand, dolomitic limestone
6.0-6.5
Johnny's Selected Seeds
Screened sphagnum peat moss, sedge, black peat, compost, perlite, and triple superphosphate
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Pargro Peatwool Fine
Pargro
Peat moss, Pargro granulated rockwool, wetting agent, lime, starter fertilizer
5.4-6.2
Paygro Natural Potting Soil
Paygro Co.
Composted hardwood bark, sand, sphagnum peat moss, reed sedge peat
6.5-7.0
Peter's Professional Potting Soil
Grace- Sierra
Canadian sphagnum peat moss, vermiculite, granite sand, bark ash, nitrogen, phosphorus, potassium, calcium and other minerals, wetting agent
5.8-6.8
Pro Mix PGX
Premier Sales
Sphagnum peat moss (fine), vermiculite (fine), wetting agent, macro- & micronutrients, dolomitic and calcitic limestone
5.5-6.2
Quick-Root Soilless Potting Mix
Peaceful Valley
Canadian sphagnum peat moss, vermiculite, compost, oystershell lime, gypsum, soft rock phosphate, bone meal, sulfate of potash, kelp meal
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Redi-Earth Potting Soil
Grace-Sierra
Canadian sphagnum peat moss, vermiculite, nitrogen, phosphorus, potassium, calcium and other minerals, wetting agent
5.2-6.3
Sogemix Plug & Germinating Mix
Sogevex
Sphagnum peat moss (fine), vermiculite (fine), wetting agent, macro- & micronutrients, dolomitic and calcitic limestone
5.5-6.2
SI-6 Seedling & Germinating Mix*
Southern Importers
Composted pine bark, composted peanut hulls, Canadian sphagnum peat moss, vermiculite, perlite, wetting agent, gypsum, starter fertilizer, dolomitic limestone
5.8-6.2
Strong-Lite Bedding Plant Mix
Strong-Lite
1/4" fully composted pine bark, medium vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
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Strong-Lite Germination Mix
Strong-Lite
Medium vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
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Strong-Lite Vegetable Mix
Strong-Lite
Coarse vermiculite, sphagnum peat moss, perlite, starter fertilizer, wetting agent
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Sunshine #3
Sun Gro*
Sphagnum peat, vermiculite, starter fertilizer, wetting agent, dolomitic limestone
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Sunshine #4 and #5
Sun Gro
Sphagnum peat, fine perlite, starter fertilizer, wetting agent, dolomitic limestone
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Terra-lite Perlite Plug Mix
Grace-Sierra
Peat moss, vermiculite, perlite, wetting agent, starter fertilizer
5.3-6.3
Terra-lite Plug Mix
Grace-Sierra
Peat moss, vermiculite, wetting agent, starter fertilizer
5.3-6.5
Low pH mix 4.8-5.9
Uncle Malcolm's Organic Planting Mix
Peaceful Valley
Canadian peat moss, composted fir, sterilized mushroom compost (composted straw, sphagnum moss, horse and chicken manures, cottonseed and soybean meals, gypsum, sulfur), compost (dried poultry waste, bonemeal, bloodmeal, feather meal, dolomitic limestone)
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Uncle Malcolm's Organic Potting Mix
Peaceful Valley
Sphagnum peat moss, perlite, volcanic pumice, earthworm castings
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V-Mix
Lambert Peat Moss
Peat moss, perlite, vermiculite, limestone, nutrients, trace elements, wetting agent
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Recipes for Starting Seeds
Mixes for starting seeds must be very light and provide a lot of air space to prevent root diseases. Seedling soil mixes may or may not contain nutrients because seedlings are often transplanted very quickly after germination.
Seed mix #1:
5 parts compost (well rotted)
4 parts topsoil (loam)
1-2 parts sharp sand
1-2 parts leaf mold
1 part sphagnum peat moss
2 tablespoons lime
Seed mix #2:
2 parts sifted compost
4 parts sphagnum peat moss
1 part perlite
1 part vermiculite
4 oz. lime
Seed mix #3: Standard soilless seed starting mix
50 to 75 percent sphagnum peat moss
25 to 50 percent vermiculite
5 lbs. of ground limestone per cubic yard of mix
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Organic seedling mix:
6 gallons sphagnum peat moss
1/4 cup lime
4.5 gallons vermiculite
4.5 gallons compost
1 1/2 cups fertility mix made of:
2 cups colloidal (rock) phosphate
2 cups greensand
1/2 cup bone meal
1/4 cup kelp meal
Organic seedling mix:
10 gallons of 2-year-old leaf mold, sifted
10 gallons sifted compost
5-10 gallons sphagnum peat moss
5 gallons perlite
5 gallons coarse river sand
2 cups blood meal
6 cups bone meal
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Mixes for potted plants require the addition of nutrients either from natural forms such as bloodmeal, bonemeal or rock phosphate, or from synthetic fertilizers such as calcium nitrate or potassium superphosphate. Locally available sources of nitrogen might be animal manures, fish products, dried blood, and legumes such as alfalfa or clover. Phosphorus can be supplied by bonemeal or rock phosphate. Wood ashes contain 10% potassium. Vermiculite also contains some potassium.
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