Call Us Today! 319.643.5550Business Hours Monday - Friday 8:30am - 5pm  

Soil Mixtures and Soil Amendments

Need some assistance determining how many bags of soil you’ll need to fill your pots, packs or flats? Use this chart.

Jump to a section

Conventional Greenhouse

Germination

BLP#1 Germination Mix

Standard all-purpose peat-based germination mix. This germination mix is suitable for most starting applications, including annuals, perennials, and veggies. It is charged with micronutrients and a phosphorus-heavy starter fertilizer. Wetting agent added to facilitate easy watering. Recommended use – plug trays and inserts.

ingredients: Sphagnum peat moss, medium vermiculite, dolomitic limestone, gypsum, 10-50-10 fertilizer, trace elements and micronutrients, wetting agent. Comes in 3ft3 bags.

BLP#1A Plug Mix

A slight variation on the germination mix, this mix is designed for the use of plug trays in production. The addition of fine perlite to this mix facilitates moisture distribution and retention in your plug trays.

ingredients: Sphagnum peat moss, medium vermiculite, fine perlite, dolomitic limestone, gypsum, 10-50-10 fertilizer, trace elements and micronutrients, wetting agent. Comes in 3ft3 bags.

Growing

BLP#2 Growing Mix Peat-Based

Standard all-purpose peat-based growing mix. This growing mix is suitable for most applications, including annuals, perennials, and veggies. It is a neutral medium, no fertilizer added, which means that growers can customize the amount of fertilizer charge they provide to the plants. Perfect for growers who prefer to add their own fertilizer to the mix, or for fertigation applications.

ingredients: Sphagnum peat moss, coarse vermiculite, coarse perlite, dolomitic limestone, gypsum, wetting agent. Comes in 3ft3 bags.

BLP#4 Growing Mix Bark-Based

Our most popular mix, this is a standard all-purpose bark-based growing mix. This growing mix is suitable for most applications, including annuals, perennials, and veggies. It is especially good for hanging baskets. While some peat-based growing mixes dry out and come away from the edge of the pots, making water retention difficult, this higher-porosity mix fills the edges of the pots even when dry, ensuring even wetness and water retention. It is charged with standard calcium nitrate fertilizer, and the bark makes for excellent soil conductivity.

ingredients: Composted pine bark, sphagnum peat moss, coarse perlite, coarse vermiculite, dolomitic limestone, gypsum, calcium nitrate, wetting agent. Comes in 3ft3 bags.

BLP#5 Perennial Mix

Another bark-based mix, this mix has higher porosity than the #4 Growing Mix, and thus is suitable for most perennials, including trees and shrubs. Frequent uses include mums, perennial grasses, shrubs, and certain trees. This mix is better for trees that prefer to remain moist, so it is not ideal for upland perennials but great for lowland perennials.

ingredients: Composted pine bark, sphagnum peat moss, coarse perlite, dolomitic limestone, gypsum, calcium nitrate, wetting agent. Comes in 3ft3 bags.

Organic Mixes

Organic Germination Mixes

BLP#10 Organic Germination Plus Mix

Organic peat-based germination mix plus compost. This germination mix is suitable for most applications, including annuals, perennials, and veggies, but is designed with the organic vegetable grower in mind. Compost is added to increase the proportion of humic acid in the germination medium. It is charged with natural ingredients, and is suitable for organic use. Do not hesitate to contact us for information regarding organic certification.

ingredients: Sphagnum peat moss, medium vermiculite, fine perlite, organic compost, dolomitic limestone, organic bone meal, sulfate of potash, rock dust, organic soy meal, gypsum, organic wetting agent. Comes in 3ft3 bags.

BLP#12 Organic Germination Mix

Organic peat-based germination mix without compost. This germination mix is suitable for most applications, including annuals, perennials, and veggies, but is designed with the organic vegetable grower in mind. Compost is left out, for growers who prefer to mix their own compost into the medium. This mix is recommended as-is for growers of micro-greens. It is charged with natural ingredients, and is suitable for organic use. Do not hesitate to contact us for information regarding organic certification.

ingredients: Sphagnum peat moss, medium vermiculite, fine perlite, dolomitic limestone, organic bone meal, sulfate of potash, kelp meal, soy meal, rock dust, gypsum, organic wetting agent. Comes in 3ft3 bags. (Vegan formulation also available, in batch quantities only – ask for details.)

Organic Growing Mixes

BLP#11 Organic Growing Mix Plus

Organic peat-based growing mix plus compost. This growing mix is suitable for most applications, including annuals and veggies, but is designed with the organic vegetable grower in mind. Compost is added to increase the proportion of humic acid in the growing medium. It is charged with natural ingredients, and is suitable for organic use. Do not hesitate to contact us for information regarding organic certification.

ingredients: Sphagnum peat moss, coarse vermiculite, coarse perlite, organic compost, dolomitic limestone, organic bone meal, sulfate of potash, rock dust, organic soy meal, gypsum, organic wetting agent. Comes in 3ft3 bags.

BLP#13 Organic Growing Mix

Organic peat-based growing mix without compost. This germination mix is suitable for most applications, including annuals and veggies, but is designed with the organic vegetable grower in mind. Compost is left out, for growers who prefer to mix their own compost into the medium. This mix is recommended as-is for growers of micro-greens. It is charged with natural ingredients, and is suitable for organic use. Do not hesitate to contact us for information regarding organic certification.

ingredients: Sphagnum peat moss, medium vermiculite, fine perlite, dolomitic limestone, organic bone meal, sulfate of potash, kelp meal, soy meal, rock dust, gypsum, organic wetting agent. Comes in 3ft3 bags.

Organic Soil Blocking Mix

Organic peat-based germination and growing mix designed for soil-blocking. This soil mixture is suitable for most applications, including annuals and veggies, but is designed with the organic vegetable grower in mind. It is especially suited for starting plants in soil blocks, which alleviates the need for plastic containers in the growing process. It is charged with natural ingredients, and is suitable for organic use.

Instead of plastic plug trays or inserts, growers use wood blocks to compress the soil into “blocks,” which are then seeded with the sides and bottoms of the blocks exposed to the air. This makes for greater air-pruning of the roots, creating a more robust and branching root structure for the seedlings that are then planted in the field.

ingredients: Sphagnum peat moss, medium vermiculite, organic bone meal, dolomitic limestone, sulfate of potash, organic kelp meal, rock dust, gypsum, organic wetting agent. Comes in 3ft3 bags.

All Purpose Potting Soils

BLP All-Purpose Potting Soil

BLP All-Purpose Potting Soil – This all-purpose potting soil is made from Iowa-harvested hypnum peat, also known as composted reed sedge peat, Canadian peat moss, sand, composted mushroom substrate, and perlite. This mixture is suitable for most applications, including houseplants (tropicals), annuals, perennials, and veggies. The hypnum retains moisture so well that no wetting agent is required in the mix.

ingredients: Iowa hypnum, Canadian sphagnum peat moss, coarse perlite, sand. Comes in 40qt and 20qt bags.

BLP Organic Potting Soil


The OMRI Listed retail version of our organic growing mix.

ingredients: Sphagnum peat moss, coarse vermiculite, coarse perlite, dolomitic limestone, organic bone meal, sulfate of potash, organic kelp meal, soy meal, rock dust, gypsum, organic wetting agent. Comes in 1ft3 bags.

Available in batch quantities only. Contact us for batch sizes and pricing.
Raised Bed Mix

Heavy on compost and topsoil to be used in large containers and raised beds. Includes beneficial microbes and mycelium to strengthen plants while protecting from disease and pests. This is designed for multi-year use so no need to remove and replace soil, simply add more as needed year after year!

ingredients: Iowa harvested hypnum peat, organic compost, organic processed pine fibers, coarse perlite, dolomitic limestone, gypsum, organic soy meal, organic bone meal, sulfate of potash, kelp meal, and rock dust. Comes in 1.5ft3 bags.

Tree and Shrub Mix

High porosity, dense growing mix designed for use with trees and shrubs.

ingredients: Iowa hypnum, composted pine bark, composted mushroom substrate, Canadian sphagnum peat moss, coarse perlite, wetting agent. Comes in 1yd3 bags.

Exotic Fir Mix

Another acidic mix, this one is designed for acid-loving trees, especially firs.

ingredients: Composted pine bark, coarse perlite, calcine clay, sphagnum peat moss, dolomitic limestone, gypsum, wetting agent. Comes in 1yd3 bags.

African Violet Mix

Known for requiring acidic soils, African violets deserve their own special mix. The pH on this mix, however, is designed to work well with all acid-loving plants.

ingredients: Sphagnum peat moss, coarse perlite, coarse vermiculite, dolomitic limestone, gypsum. Comes in 3ft3 bags.

Create Your Own

You can create your own specialty mix based on any of the above available soil mixtures by adding your favorite soil amendment(s) or fertilizer(s). We can consult with you to ensure you remain within the ideal pH and soil conductivity levels, as well as mix rates for each of the amendments/fertilizers you’d like. NOTE: Create Your Own mixes must be bought on a per-batch basis, and costs are calculated according to the raw material and labor costs. We can estimate the number of 3ft3 bags you’ll get from a batch, and will adjust the price accordingly, but the entire batch must be purchased (usually somewhere between 14-21 3ft3 bags per batch, depending on the base mix). Lead times on Create Your Own mixes vary depending on seasonal availability. Contact for details and estimates.

Soil Amendments

Sustane Bolster MycoBio

OMRI Listed mycorrhizal inoculant with bacterial biostimulant dormant in dried compost, water-activated. This amendment promotes vigorous early growth, enhanced root growth, improved nutrient uptake, and enhanced stress tolerance. Contains 30% compost, which delivers humic acid. Species list: bacillus subtilis, bacillus pumilus, bacillus megaterium, bacillus licheniformus, bacillus amyloliquifaciens; rhizoglomus irregularis, claroideglomus etunicatum, septoglomus deserticola, rhizoglomus clarum.

Horticultural grade vermiculite (A-2 medium)

4ft3 bags – Great for covering seeds in trays and flats and decent germination medium overall. Also great for mixing into seeders with seed mixes (e.g., prairie seed mixes or cover crop seed mixes) to spread seeds out over larger areas.

MycoApply Endo mycorrhizal inoculant

OMRI Listed mycorrhizal inoculant dormant in clay pellets, water-activated. This amendment is great for increasing root strength and improving nutrient uptake, as most plants will form a symbiotic relationship with the mycorrhizal fungi. Use of mycorrhizal fungi has been linked to increased drought tolerance, better soil moisture retention, and healthier plants overall. Species list: glomus intraradices, glomus mosseae, glomus aggregatum, glomus etunicatum. Sold by the pound or in 40lb bags.

Cowsmo compost

Chock full of humates, this compost from Wisconsin is great for amending hard-packed clay pan soils. It increases organic matter in soil, and increases soil porosity and nutrient uptake. Sold in 1-ton (roughly 1yd3) bulk totes.

Horticultural grade peat moss

3.8ft3 compressed bales

Horticultural grade vermiculite (A-3 coarse)

4ft3 bags

Expanded perlite – coarse

4ft3 bags

Expanded perlite – fine

4ft3 bags