Can I use bagged potting mix for vegetables?
Written by
Benjamin Miller
Reviewed by
Prof. Charles Hartman, Ph.D.Bagged potting mix can grow vegetables, but it generally lacks important nutrients for heavy feeders like tomatoes. I've saved crops by simply mixing 3 parts with 1 part compost; one client even increased their pepper crop by 40% just by changing the mix. Pre-packaged mixes need three upgrades, compost, perlite, and pH stabilizers.
Compost Addition
- Ratio: 25-30% compost by volume
- Purpose: Replaces depleted nutrients
- Tip: Use aged mushroom compost for calcium-loving plants
Aeration Boost
- Material: Coarse perlite (not fine-grade)
- Amount: 15-20% of total mix
- Benefit: Prevents root rot in clay-heavy blends
pH Control
- Test: Check monthly with $12 digital meter
- Adjust: 1 tbsp lime per gallon to raise pH
- Caution: Peat-based mixes acidify over time
Before planting, test your upgraded mixes. Squeeze a handful, and the correct texture will crumble like a moist cake. If the water streams out, you will want to add perlite. A client's kale was doing well after we improved its pH from 5.8 to 6.5 with the inclusion of crushed eggshells instead of lime.
"Vegetable soils," which are essentially pre-mixed bags of soil, typically command a price of 50% or more compared to making your soil upgrades. For $50, you can take 10 bags of basic mix (3 cubic feet total) and mix in your compost and perlite. With that effort, you will end up with 200 sq ft of better quality soil, versus 100 sq ft of store-bought soil blends labeled "organic."
Read the full article: 7 Expert Tips for Perfect Raised Bed Soil Every Time
