Seed Starting Mix - made with Biochar

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Sustainably produced, peat-free soil that naturally supports healthy plant growth.

Carbon neutral

Made In The US

Recyclable Packaging


Biochar is a horticultural charcoal that holds onto oxygen and nutrients while also storing microbes and carbon in the soil.

Worm Castings are nutrient-rich organic matter produced by worms that provide plants with essential nutrients.

Mycorrhizae are beneficial microorganisms that form a symbiotic relationship with plant roots, allowing the plants to absorb more nutrients.

Sand has large grain size, coarse texture, and high silica content to support soil drainage.

Pine Bark Fines are a byproduct of the mulch industry which enhance soil structure and improve aeration.

Compost helps reduce waste in landfills by turning green waste and wood waste into a useful source of nutrients for plants.

Most commercial potting mixes contain peat, the mining of which releases huge amounts of carbon into the atmosphere. Not only does this product leave the peat (and carbon) in the ground where it belongs, but the process used to produce the biochar in this potting soil actually removes carbon from the atmosphere.

Guaranteed Analysis 0.70-0.04-0.06

Total Nitrogen (N) ..................................0.70%

     0.70 % Water Insoluble Nitrogen

Available Phosphate (P2O5)...................0.04%

Soluble Potash (K2O).............................0.06%

Derived from compost, worm castings


Soil Amending Guaranteed Analysis

Active Ingredients

     Rhizophagus irregularis.........4 propagules/g

     Funneliformis mosseae..........2 propagules/g

     20% Wood biochar

Inert Ingredients

     80% Total Other Ingredients (inert as non-plant food ingredients)

Ingredients: compost, bark fines, biochar, sand, worm castings, and microbes

Biochar may reduce soil density and increases soil aeration. Mycorrhizae may promote root mass expansion and nutrient efficiency.

You'll want a seed starting tray as well as some high quality seeds. Seedlings don't need much light, but check the directions on your seed packet for guidance on this.


Seedlings: Select a well-draining seed tray or planter and fill it with Rosy Soil. Follow your seed packet's instructions regarding sowing depth and spacing. Avoid over-seeding as too many seeds in a small area can hinder growth.

Propagation: Partially fill a well-draining pot with Rosy Soil. Gently place your cutting into the soil, ensuring the roots are covered. Cover with additional Rosy Soil, leaving at least an inch at the top for easy watering.


Water slowly and thoroughly unitl it drains from the bottom. Aim for light, even moisture throughout the mix.


Place the tray or container in a warm location with indirect sunlight or under grow lights. Keep the soil consistently moist, but not damp, and adjust watering as needed.


Once the seedlings or propagated cuttings have grown and the weather permits, transplant them into larger pots or your garden.

Nutrient Dense

Boosts soil aeration, drainage, and nutrient uptake to help plants flourish


Plant-based packaging in convenient sizes for indoor plant parents


Made from eco-friendly, high-quality ingredients (biochar, compost, mycorrhizae, pine bark fines) and is free from peat & synthetic additives.

Which Microgreens Kit Is Right For You?

Growing Methods hydroponic Hydroponic hydroponic soil soil hydroponic
Growing Medium Proprietary ‘seed quilts’ made from coconut fiber Virgin fluff fibers produced from non-chlorine bleached spruce wood none coco coir coco coir Jute matt
Includes a light no yes no no no no
Included seeds 2 varieties - varies 3 varieties Red Cabbage, Radish and Mustard none 4 varieties. Radish, Arugula, Beets and Tatsoi 4 varieties. Arugula, Beets, Komatsuna and Radish 6 varieties. Radish, Kale, Rainbow Mix, Mustard, Spicy Mix and Broccoli
USDA Organic Seeds? Some, not all Yes NA No No Yes
Grow Area 1 x Large 3 x Medium 1 x Medium/Large 1 x Small 1 x Medium 3 x Small
Refill Cost $$ $$$ $ $$ $$ $$

Which Grow Light Is Right For You?

Wattage 20W / 40W 20W 11W 16W / 32W 7W
PPF Small: 23.7 μmol/sec; Large: 42 μmol/sec 25.95 μmol/sec 17 μmol/sec - 7.3 μmol/sec
Efficacy (PPF/W) 1.05 - 1.2 1.3 1.55 - 1.05
Color Temperature 3000K 3000K 3000K 3914K 2700K
Mounting Hanging from wall or ceiling Inside a pendant or desk lamp Under cabinet or on a wall Under cabinet, wall or vertically Inside a pendant or desk lamp
Suitable For Anything Anything Houseplants, Herbs, Leafy Greens Anything Small herbs, seed starting
Water Resistant No No No Yes No
Cost $$$ $$ $$ $$ - $$$$ $

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Peat moss has been a common ingredient in commercial potting mixes since the 1960s. However, it's obtained by extracting peat bogs, which are vital ecosystems that store carbon. Rather than release that carbon into our atmosphere, this product uses biochar as its base.

Rosy’s seedling mix is all-natural, peat free, and made from biochar. 

They've consciously sourced ingredients not only because they’re great for your plants but also because they’re good for our planet. 

Unlike traditional potting soil ingredients that are environmentally taxing, biochar potting mix only contains natural and carbon-negative amendments.

They use carbon-negative, organic ingredients to create the best indoor plant potting mix.

Typically, these organic materials are sent to a landfill, where they release methane and CO2 — two potent greenhouse gases. But by redirecting these organic materials from landfills and stabilizing their carbon structure, we prevent the release of those greenhouse gases.

Essentially, they turn our house plant soil into a carbon sink, which means it helps to remove CO2 from the atmosphere.

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