Purple Cow Seed Starter Mix is an OMRI Listed, living media containing beneficial biology and nutrients to get your plants off to a healthy start. Seed Starter Mix is a fine-textured blend that promotes rapid germination and vigorous seedlings. Our mix includes Purple Cow Compost, sphagnum peat, perlite, vermiculite, OMRI Listed granular fertilizer, and mineral complex. It is intended for seed starting in trays, blocks or small containers - balancing drainage and wicking action to keep roots moist.

OMRI Certificate

Benefits of PCO Seed Starter Mix

  • Increased germination
  • Good seedling vigor
  • Sturdy seedlings at transplanting
  • Save money with less watering and fertility inputs
  • More effective cultivation due to compact, healthy upright plants
  • Crafted on our computerized blending line for consistent media every time


"We have tried every other seed starter out there but always come back to Purple Cow...nothing grows like Purple Cow."

P.T. Bjerke, Supercharge! Foods

"I'm extremely pleased with how everything has done...I'm definitely using their Seed Starter for next growing season...used Purple Cow Seed Starter for the trays then their compost. I'm sold."

Brad Wynne, VegOut Gardens

"Of all the seed starters we've trialed over the years theirs has the best consistency as well as overall quality year after year."

Harmony Valley Farm

"Purple Cow has been our exclusive seed starting mix for the past six years. Product consistency and performance more than exceed our expectations. We seed great seed germination and growth far beyond the suggested use."

Paul and Laura Phelps

"It is a proven winner that we openly recommend. Purple Cow, the knowledgeable team and the company's integrity and passion for soil are the best!"

Serenity Farm

How much material do I need?

A 1 cubic foot bag fills

Plug Flats

288 cells - 11 flats

200 cells - 10 flats

128 cells - 7 flats

72 cells - 6 flats

50 cells - 5 flats

Pro Trays

72 cells - 7 flats

38 cells - 6 flats

24 cells - 5 flats

A 2 cubic yard supersack fills

Plug Flats

288 cells - 625 flats

200 cells - 540 flats

128 cells - 415 flats

72 cells - 330 flats

50 cells - 270 flats

Pro Trays

72 cells - 415 flats

38 cells - 340 flats

24 cells - 225 flats

General Calculations

A 1 cubic foot bag is equivalent to 26 Quarts.

A 2 cubic yard supersack is equivalent to 1,404 Quarts.

There are 54 cubic feet in a 2 cubic yard supersack.

For 3" pots or larger we recommend using one of the other Purple Cow Organics' mixes.