Research-backed container soil mix recipes for 33 plants
Container soil chemistry is the difference between a tomato that flowers in July and one that quietly drops blossoms all season. Each recipe below is a starting point calibrated for one plant family — pepper, mint, blueberry, eggplant — built from peer-reviewed studies and university-extension fact sheets so you're not guessing at percentages.
Every recipe scales to your container size: the percentages stay fixed (because soil ratios don't care about pot size), but the per-container amendments (kelp meal, mycorrhizae, bone meal) and the total volume to mix scale linearly. Use the interactive calculator linked from each recipe page to compute the exact quantities for your pot.
Pick a plant below — recipes are grouped by category (vegetables, herbs, fruits, houseplants) and sorted alphabetically. The full ingredient list, pH and EC range, light requirements, and growing notes live on each recipe page.
Vegetables
Dual-purpose root + greens crop that wants a loose, well-drained mix with adequate boron.
Heavy-feeding cool-season brassica that needs even moisture and a fertile, slightly alkaline mix.
Nitrogen-fixing legume that fruits hard in a light, low-N mix with Rhizobium inoculant.
Cool-season brassica that forms tight heads in a fertile, moisture-retentive, near-neutral mix.
Direct-seeded taproot crop that demands a loose, low-compost, stone-free sandy mix to grow straight.
Coco-coir-heavy container mix for cucumbers — highest CEC base per research, paired with pumice for chlorophyll and aeration.
Heat-loving Solanaceae that fruits hard in a warm, evenly moist 5-gallon root zone.
Fall-planted, cold-vernalized bulb crop that wants free-draining, organic-rich soil at near-neutral pH.
Vigorous, frost-hardy brassica that wants loamy organic-rich soil and steady nitrogen.
Shallow-rooted cool-season green that thrives in a moisture-retentive, vermicompost-rich mix.
Shallow-rooted heavy feeder early, then tapering N — wants loose, organic, evenly moist soil.
Research-backed container soil mix for peppers (Capsicum spp.) — vermicompost-forward with charged biochar for CEC and BER-preventing calcium amendments.
Simplified pepper mix using Organic Mechanics Biochar Blend (or similar all-in-one) in place of separate biochar + compost + zeolite + minerals + meal amendments.
Acidic, low-N container mix for potatoes — the yield driver is the hilling technique, not the soil composition.
Loose, lean, deeply-loosened mix so roots size up smooth and round without forking.
Cool-season nitrogen-hungry green that prefers a near-neutral, well-amended container mix.
Container soil mix for bush and vining squash — pumice-heavy for water efficiency, vermicompost for slow N.
Heavy-feeder tomato soil mix optimized for indeterminate and determinate varieties in containers.
Simplified tomato mix using Organic Mechanics Biochar Blend (or similar all-in-one) in place of separate biochar + compost + zeolite + minerals + meal amendments.
Herbs
Fertile, evenly-moist mix for big leafy harvests from a heat-loving annual.
Well-drained, fertility-balanced mix for a hardy perennial allium.
Light, fast-draining mix for cilantro — bolts in heat, hates wet feet, resents transplanting (direct-sow only).
Deep, slightly acidic, organically-rich mix for a tall taproot annual.
Moisture-loving herb mix for mint — high water retention, steady fertility, and always solo (mint chokes neighbors).
Well-drained, slightly alkaline mix for a vigorous spreading Mediterranean herb.
Deep-rooted biennial herb that wants a moist, fertile, free-draining mix.
Lean, gritty, sharply-drained Mediterranean mix — root rot is the #1 killer.
Sandy-loamy, sharply-drained mix for a drought-tolerant Mediterranean shrub-herb.
Gritty, low-fertility mix mimicking the dry, gravelly slopes thyme is native to.
Fruits
Strictly acidic ericaceous mix dominated by pine bark fines and peat — non-negotiable pH 4.5-5.2.
Container soil mix for roselle (Hibiscus sabdariffa) — sandy-loam-mimicking, biochar-enhanced for salinity tolerance.
Free-draining, organically-rich, slightly acidic mix for sweet container berries.
Houseplants
How these recipes are built
Each recipe starts with a base structure (a quality bagged potting mix or a hand-mixed substrate) and adds three categories of ingredients: components (coco coir, perlite, pumice, vermicompost, biochar) blended by percentage of volume; amendments (kelp meal, mycorrhizae, bone meal, gypsum) dosed per gallon of container; and a list of citations (university extension fact sheets, peer-reviewed papers) backing the choices.
We chose ingredient ratios using a small number of consistent rules: heavy feeders (tomato, pepper, eggplant, brassicas) get more compost or vermicompost; Mediterranean herbs (rosemary, thyme, oregano, sage) get more pumice/sand for drainage and lean fertility; root crops (carrot, beet, radish) get a low-compost loose mix to grow straight; blueberries get an ericaceous (acidic) mix dominated by pine bark fines and sphagnum peat. The full reasoning is on each recipe page.
For the in-app interactive version that saves mixes to your plot plants and tracks applied dates, see the garden.gg dashboard.