Dr Forest

Made by growers, backed by science

Handmade in Stockport

Our Tomato Fertiliser 3-4-6 is a carefully formulated blend of premium organic ingredients to produce a slow-release powdered fertiliser crafted exclusively for tomatoes that taste like tomatoes should – intensely sweet, rich, and complex, with heavy, consistent harvests all season long.

Using a proven 3-4-6 ratio that has performed strongly in grower comparisons and research for over 30 years, Dr Forest combines traditional, time-tested organic materials with premium regenerative ingredients to deliver an outstanding all-in-one tomato feed.

Benefits of Our 3-4-6 Organic Tomato Fertiliser

• Potassium Rich NPK Ratio: Precise 3-4-6 formulation – an optimal blend for superior flavour and yield, supported by extensive research on tomato nutrition.
• High Potassium Content: One of the highest potassium levels among major tomato-specific organic fertilisers – linked to documented increases in Brix levels, lycopene, vitamin C, and taste-panel scores for exceptional fruit quality.
• Living Biology: Includes fermented biochar and effective microorganisms (EM) – proven to promote plant growth, suppress diseases, and enhance microbial diversity.
• Trace Mineral Boost: Enriched with mineral-rich seaweed meal, basalt rock dust, and clay minerals – providing trace elements that enhance antioxidants, extend shelf life, and improve stress resistance.
• High Calcium Content: Supplies ample calcium to support robust plant health and prevent blossom end rot – particularly valuable as calcium is often limited in some fertiliser types.
• Premium Composition: A blend of 13 premium plant-based ingredients, including Yorkshire Polyhalite and Scottish Seaweed. 
• Superior Harvest Results: Heavier crops of firmer, more uniform fruit with 15–25% longer shelf life compared to higher-nitrogen alternatives.
• Handcrafted Quality: Made in the UK in small batches by hand, ensuring consistency and care in every bag.
• Versatile All-in-One Solution: A single, convenient product suitable from transplant to final harvest – ideal for garden beds, raised beds, containers, and polytunnels.

Why use organic fertilisers?

1. Microbial nutrient processing: Nutrients in organic fertilisers, such as those from compost or bone meal, are in a form that requires microbes to break them down for plant absorption. This process generates secondary metabolites that enhance flavour and aroma – a key reason why organic produce often excels in taste, scent, and nutrient density.
2. Reduced nitrate levels: Dramatically lower nitrate content in fruit (typically 30–50% lower compared to synthetic fertilisers) – resulting in cleaner, healthier, and better-tasting tomatoes.
3. Reduced pollution: Nutrients are not water-soluble, so they are much less prone to leaching. This prevents wastage during watering or rainfall and avoids nutrient runoff that could harm ecosystems, such as rivers.
4. Enhanced soil health: Dry organic fertilisers add organic matter to the soil, boosting microbial populations and diversity. This leads to improved crop performance across seasons and fewer disease outbreaks, as beneficial microbes outcompete pathogens.
5. Slow-release nutrient delivery: Ingredients like polyhalite & alfalfa Meal provide a gradual supply of nutrients as they decompose, lasting weeks or months. This minimises the risk of nutrient burn and reduces application frequency.
6. Improved soil structure and water retention: Organic matter binds soil particles, enhancing aeration, drainage, and moisture-holding capacity for stronger root systems and greater drought resilience.
7. Support for biodiversity: They encourage beneficial organisms, such as earthworms and mycorrhizal fungi, fostering a balanced ecosystem that naturally deters pests and sustains long-term soil fertility.
8. Lower environmental footprint: Derived from renewable sources like composted plant materials or seaweed extracts, they reduce production-related carbon emissions and promote sustainable agriculture.

Directions for Use

Soil Preparation

• Soil Beds: 100–300 grams per square metre. Work into the top 10–15 cm of soil surface. If your soil is fertile you can use the lower rate and if your soil is poor & depleted we recommend using the higher rate. 
• Single Plants: Mix 2 - 2.5 tablespoons (30 - 37.5 grams) into the soil around the plant when planting. Leave a 10 cm gap between the stem and the fertiliser ring.
• Potted Plants: Mix 7.5 – 15 grams per litre of soil. After mixing, ensure good drainage in containers to prevent waterlogging, which can reduce nutrient uptake. We recommend lower rates when using mycorrhizal funghi to prevent phosphorous inhibiting colonisation. 

Ongoing Feeding Start applying fertiliser 10–14 days after transplanting (once plants are established and showing new growth). Apply every 2–3 weeks during active growth (vegetative to early fruiting), then reduce to every 3–4 weeks as fruits mature to focus on quality, flavour and aroma over quantity. Monitor for signs of excess nitrogen (dark green leaves, leggy growth, few flowers/fruits) and adjust downward.

• Rows: 75–150 grams each side per metre of tomato plants. Apply in a narrow band 10–15 cm from the stems.
• Single Plants: 2 - 3 tablespoons (30 - 45 grams) per plant. Apply in a narrow band around the plant, 10–15 cm from the stem.
• Potted Plants: Apply 1 - 1.5 teaspoon (5 - 7 grams) per 10 cm in pot diameter. (For example: 3 - 4.2 teaspoons or ~15 - 21 grams for a 30 cm pot diameter; 6 - 8.4 teaspoons or ~30 - 42 grams for a 60 cm pot diameter.) Apply evenly as a narrow band around the outer edge of the pot (away from the stem). Lightly scratch or mix into the top 2–5 cm of soil. 

Application Tips

• Use a tablespoon (not a dessert spoon). If unsure, 3 teaspoons = 1 tablespoon, or use weight measurements for accuracy.
• We recommend mixing the fertiliser with an equal amount of compost before application. This reduces dust, coats the granules in microbe-rich compost to aid nutrient breakdown, and improves even distribution.
• Always water thoroughly after application to activate the slow-release nutrients, help them reach the roots, and prevent any minor surface buildup (especially important in pots).
• Observe your plants and adjust:
  • Pale or yellow lower leaves → possible nutrient deficiency → increase toward the higher end of the range or apply more frequently (closer to every 2 weeks).
  • Excessive dark green foliage, leggy growth, or few fruits → too much nitrogen → reduce amount or frequency (stretch to 4 weeks or skip an application).
• This fertiliser includes calcium to help prevent blossom end rot—consistent even moisture (avoid over- or under-watering) is also key.

Late-Season Care Reduce feeding frequency slightly toward the end of the season (last 3–4 weeks) or skip entirely once most fruit is set and ripening. Ease off watering a bit when fruit is ripening—this concentrates sugars and acids in the tomatoes for bolder, sweeter flavour without cracking or splitting from sudden water uptake.

Additional Notes

• Store in a cool, dry place. Keep out of reach of children and pets. Wear gloves if sensitive to dust.
• Organic and slow-release—safe for beneficial insects, pollinators, and soil health when used as directed.

Supporting Research on Organic Fertilisation for Flavour and Yield

• Gao et al. (2023) meta-analysis of 107 studies (Applied Sciences): Organic fertilisers significantly increased vitamin C by ~19% and lycopene by ~24% compared to no fertiliser, contributing to improved nutritional quality and flavour.
• Multiple studies (2021–2024), including meta-analyses in European Journal of Agronomy and Scientia Horticulturae: Higher potassium-to-nitrogen ratios support gains in sweetness, aroma compounds, and sensory scores, often with minimal yield penalty.

Recommended Amendments to Enhance Results 

To further optimise flavour, yield, and overall plant health, consider incorporating these complementary amendments alongside your core fertiliser regime. Each has been selected based on robust scientific evidence showing benefits for tomatoes, particularly in organic or regenerative systems.

• Mycorrhizal Fungi: Inoculate seedlings or apply at planting. We recommend the "slurry method." AMF form a symbiotic relationship with tomato roots, extending the root system for better nutrient and water uptake. Studies show AMF inoculation increases fruit yield (up to 20–50% in some trials), enhances soluble solids (Brix levels for sweetness), boosts lycopene (up to 24–53%), vitamin C, and aroma compounds, while improving drought tolerance and disease resistance. Meta-analyses and field trials confirm higher antioxidant content and sensory scores in mycorrhizal tomatoes.
• Seaweed Extract : Apply as a foliar spray. Apply every 7-14 days. Seaweed extracts act as bio stimulants, rich in natural growth hormones, trace elements, and bioactive compounds. Research demonstrates increases in yield (up to 65% under stress), fruit set, soluble solids, lycopene, flavonoids, and overall flavour profile. They also enhance stress resilience (drought, salinity) and nutrient efficiency, with meta-analyses supporting improved sweetness, aroma, and nutritional quality.
• Liquid Calcium Sulphate (Gypsum): Apply as a soil drench. Use every 2-4 weeks. Gypsum supplies readily available calcium without altering soil pH, crucial for cell wall strength. Extensive trials link gypsum application to reduced blossom end rot (a common calcium-deficiency disorder), firmer fruit, better shelf life, and maintained yields. It supports consistent fruit development and quality, especially in variable moisture conditions.
• Additional Humic Acid (or Humic/Fulvic Acids): Use as a soil drench. Apply every 2 - 4 weeks. Humic acids chelate nutrients for better uptake, stimulate root growth, and enhance microbial activity. Studies report yield increases (up to 19–30%), higher Brix/sugar content, improved nutrient density (e.g., antioxidants), and stress tolerance. They complement slow-release organics by boosting efficiency and fruit flavour/nutritional value.
• Cover Crops (e.g., Rye, Radish, or Legume Mixes): Sow in autumn/winter before tomatoes, then incorporate as green manure in spring. Cover crops build soil organic matter, improve structure, and suppress diseases. Long-term trials show higher tomato yields (equivalent or greater than bare soil), enhanced soil health indicators, and reduced foliar/fruit diseases (e.g., anthracnose).

These amendments align with regenerative principles, reducing reliance on inputs while maximising the potential of your 3-4-6 fertiliser. Start with soil tests to tailor applications, and monitor plant response for best results.

Dr Forest Organic Tomato Fertiliser 3-4-6 is an evidence-backed, flavour-focused, high-yielding organic tomato fertiliser.