Compost Tea .
- Nitrogen (N) — For leafy vegetative growth (use more early, less during fruiting to avoid excessive foliage over fruit).
- Composted manure (cow, horse, poultry, rabbit — well-aged to avoid burning).
- Blood meal or feather meal.
- Fish emulsion (liquid, fast-acting).
- Alfalfa meal or pellets.
- Worm castings/vermicompost.
- Legume cover crops (e.g., clover) tilled in.
- Phosphorus (P) — For strong roots, flowering, and fruit set.
- Bone meal (classic organic source, also adds calcium).
- Rock phosphate (slow-release, mined mineral).
- Fish bone meal.
- Bat guano (some types high in P).
- Potassium (K) — For fruit quality, disease resistance, water regulation, and overall plant vigor.
- Wood ash (from untreated hardwood — use sparingly as it raises pH).
- Kelp meal or seaweed (liquid or powder — excellent broad-spectrum with trace elements too).
- Sul-Po-Mag (langbeinite — natural mineral source of K, Mg, S).
- Composted banana peels (buried or in compost).
- Greensand (slow-release mineral).
Secondary Macronutrients
- Calcium (Ca) — Critical to prevent blossom end rot; tomatoes use a lot during fruiting.
- Crushed eggshells (slow-release — crush and add to planting hole or compost).
- Gypsum (calcium sulfate — good for calcium without raising pH much).
- Bone meal (provides both P and Ca).
- Oyster shell flour or dolomite lime (if soil is acidic).
- Dolomitic limestone (adds Ca + Mg).
- Magnesium (Mg) — Key for chlorophyll and photosynthesis (deficiency shows as yellowing between leaf veins).
- Epsom salt (magnesium sulfate — dissolve in water for foliar or soil drench; organic-approved in moderation).
- Dolomitic lime.
- Sul-Po-Mag.
- Kelp meal.
- Compost/manure.
- Sulfur (S) — For protein formation and disease resistance.
- Often comes along with other amendments (e.g., gypsum, Sul-Po-Mag, manure).
- Elemental sulfur (if needed to lower pH, but rarely primary source).
Micronutrients (Trace Elements)
These are usually supplied adequately in good compost, kelp, and diverse organic matter, but deficiencies can occur in poor or overworked soils.
- Iron (Fe), Manganese (Mn), Zinc (Zn), Copper (Cu) — For enzyme functions, chlorophyll, and growth.
- Kelp/seaweed products (rich in trace minerals).
- Rock dusts (e.g., glacial rock dust, basalt, azomite — broad-spectrum volcanic/mineral sources).
- Compost and worm castings.
- Alfalfa meal.
- Boron (B) — For fruit set, pollen viability, and cell walls.
- Kelp meal (excellent natural source).
- Borax (very sparingly — toxic in excess; only if soil test shows deficiency).
- Molybdenum (Mo) — For nitrogen fixation/uptake.
- Usually sufficient in organic matter; rock dusts help.
- Chlorine (Cl) — Rarely deficient; trace amounts in most soils/manures.
1. Amazing Deep Mineral Accumulator (especially Potassium, but also many others)
Comfrey has incredibly deep roots (up to 2–3 meters / 6–10 ft) that mine minerals from the subsoil that most plants can’t reach:
- Very high in Potassium (K) – crucial for fruit quality, size, flavor, and disease resistance in tomatoes
- High in Phosphorus (P) – great for flowering and fruit set
- Good amounts of Calcium, Magnesium, Iron, Silicon, and many trace elements
- Also contains sulfur and other nutrients
This makes it far superior to banana peels or most other “potassium sources” people use.
2. Best Uses for Tomatoes
A. Comfrey Liquid Feed / Tea (the #1 tomato booster)
- Chop fresh comfrey leaves (and stems) and soak in water for 3–6 weeks (weighted down, it stinks!).
- Dilute the dark liquid 1:10 or 1:20 with water.
- Water tomatoes every 10–14 days from flowering onward.
- Result: dramatically better fruit size, flavor, and plant health. Many old-school growers swear this alone gives prize-winning tomatoes.
B. Comfrey Mulch
- Lay whole leaves around the base of tomato plants as mulch.
- Decomposes quickly, feeds the soil directly, suppresses weeds, retains moisture.
C. Planting Hole Booster
- Put a handful of wilted or fresh comfrey leaves in the bottom of each tomato planting hole.
- Gives the young plant an immediate nutrient surge (especially potassium and phosphorus).
D. Compost Activator Supreme
- Add comfrey to your compost pile — it speeds decomposition dramatically and raises nutrient levels of finished compost.
E. Foliar Spray
- The diluted tea can also be used as a foliar feed — tomatoes absorb nutrients quickly through leaves.
3. Bonus Benefits
- Contains allantoin – promotes fast healing of damaged tissue (great for transplant shock or storm-damaged plants)
- Attracts earthworms like crazy
- Makes plants more pest and disease resistant (healthier plants = fewer problems)
- Most serious organic tomato growers consider comfrey absolutely indispensable — once you start using it, you’ll never go back!
- Most modern gardeners and homesteaders grow comfrey primarily for its outstanding value as an organic fertilizer, mulch and compost booster. It is one of the most powerful “chop-and-drop” plants in permaculture systems.