200 cell Winstrip seed tray ready for seeding
Seed Starting and Potting Mix Recipes
Search the internet and you'll find no end to the number of recipes for seed starting and potting mix. There's no one correct one, but here's the recipes I use at Berwyn Plants. I've "improved" my recipes over the last 15 years so I think these are pretty darn good. I used to use straight seed starting mix from the major manufacturers (Berger, Pro-Mix, Sunshine) but I found that the addition of perlite and nutrients helps get seedlings off to a stronger start. I also started using compost for potting perennials, but it had some shortcomings. First, compost is a method, not a specific product and bagged or homemade composts have different textures and composition and has widely varying nutrient values. Switching to amended pine fines many years ago was key.
Original Floret’s potting soil recipe (per 3.8 cu. ft. bale)
https://workshop.floretflowers.com/potting-soil-opt-in
- 1 Bale Pro-Mix Potting Soil (3.8 cubic feet)
- 5 gallons High quality screened compost
- 6 cups Bone Meal
- 3 cups Kelp Meal
- 2 cups Blood Meal
Berwyn Plants seed starting soil recipe (per 5 gallon batch, hand mixed)
- 5 gallons Berger BM2 seed starting mix
- 3 cups Fine vermiculite
- 8 Tbsp (4 oz) Bone Meal
- 4 Tbsp (2 oz) Kelp Meal
- 4 Tbsp (2 oz) Blood Meal
- 4 Tbsp (2 oz) Mycorrhizal fungi inoculant (Mico Bliss Granular, 1000 propagules/g)
Berwyn Plants potting soil recipe (Modified Floret recipe, per cu. ft, hand mixed)
- 1 cu. ft. Berger AP191 all-purpose potting mix
- 1 gallon High quality screened compost (Black Kow manure compost, Quail Ridge mushroom compost)
- 2 cups (16 oz) Fine vermiculite
- 12 Tbsp (6 oz) Bone Meal
- 6 Tbsp (3 oz) Kelp Meal
- 6 Tbsp (3 oz) Blood Meal
- 6 Tbsp (3 oz) Neem Meal
- 6 Tbsp (3 oz) Mycorrhizal fungi inoculant (Mico Bliss Granular, 1000 propagules/g)
Berwyn Plants perennial potting soil mix (per 2.5 cu. ft., machine mixed batch)
- 1 cu ft Quail Ridge Products Pine fines
- 4 gallons High quality screened compost (Black Kow, Quail Ridge, etc.)
- 4 gallons Peat Moss
- 4 gallons Coconut husk chunks (coir chips)
- 2 gallons Horticultural perlite
- 8 oz (1 cup) Controlled-release fertilizer (Florikan 18-5-12, Osmocote 19-6-12)
- 8 Tbsp (4 oz) Mycorrhizal fungi inoculant (Mico Bliss Granular, 1000 propagules/g)
- As needed -- Pine fines and perlite to complete the batch after mixing & milling