Dr Forest

Made by growers, backed by science

Handmade in Stockport

Our Potato Fertiliser 3-5-7 is a carefully formulated blend of premium organic ingredients to produce a slow-release powdered fertiliser crafted exclusively for potatoes that deliver large, starchy, flavourful tubers with earthy sweetness and excellent texture, plus consistent, high-yielding harvests all season long.

Using a proven 3-5-7 ratio optimized for superior tuber quality in potatoes – supported by recent studies on organic fertilization enhancing starch content, dry matter, and nutritional value while reducing nitrates – Dr Forest combines traditional, time-tested organic materials with premium regenerative ingredients to deliver an outstanding all-in-one potato feed focused on maximum yield and flavour.

Benefits of Our 3-5-7 Organic Potato Fertiliser

• Balanced NPK Ratio: Precise 3-5-7 formulation – an optimal blend for exceptional tuber development and flavour, with low nitrogen to promote balanced growth without excess foliage, moderate phosphorus for strong root and tuber initiation, and high potassium for starch accumulation, disease resistance, and quality, backed by research on potato nutrition.
• High Potassium Content: One of the higher potassium levels among major potato-specific organic fertilisers – linked to documented increases in starch content, dry matter, sugars for sweetness, and resistance to blight/scab, improving sensory scores for rich, earthy flavour.
• Living Biology: Includes fermented biochar and effective microorganisms (EM) – proven to promote plant growth, suppress diseases, enhance microbial diversity, and boost secondary metabolites for improved nutritional density and tuber storage quality.
• Trace Mineral Boost: Enriched with mineral-rich seaweed meal, basalt rock dust, and clay minerals – providing trace elements that elevate antioxidants, extend shelf life, and improve stress resistance for healthier, more flavourful potatoes.
• Moderate Phosphorus Emphasis: Supplies ample phosphorus to drive tuber formation and root health – key for high-yielding, uniform potatoes with superior texture and reduced hollow heart.
• Premium Composition: A blend of 17 premium plant-based ingredients, including Yorkshire Polyhalite and Scottish Seaweed.
• Superior Harvest Results: Larger, more uniform tubers with higher starch/dry matter (up to 15–30% improvements in trials) and longer shelf life compared to higher-nitrogen alternatives, plus enhanced sweetness and flavour profiles.
• 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 planting to harvest – ideal for garden beds, raised beds, containers, and allotments.

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 potatoes often excel in taste, texture, and nutrient density.
2. Reduced nitrate levels: Dramatically lower nitrate content in tubers (typically 30–50% lower compared to synthetic fertilisers) – resulting in cleaner, healthier, and better-tasting potatoes.
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.

Soil Preparation (Pre-Planting)

Incorporate lightly into the top 10–15 cm. Avoid direct tuber contact to prevent burn. This base feeding supports root establishment and early tuber set with balanced nutrients.

• Soil Beds/Raised Beds: Apply 100–130 grams per square metre. This provides moderate N (~3–4 g/m²) while emphasizing P/K for starch/flavor development—lower than heavy-yield rates to prioritize quality over volume.
• Single Plants/Hills: Mix 2–3 tablespoons (30–45 grams) into the planting hole or hill per tuber. Maintain a 10 cm gap from the seed tuber.
• Potted Plants/Containers/Grow Bags: Mix 1 - 2 teaspoons (5 - 10 grams) per litre of soil. For a standard 10–20 litre pot/grow bag: 10–20 grams total mixed evenly.

Feeding (Ongoing Maintenance) – Focus on Flavor

Start at 6–8 weeks after planting (post-establishment, during hilling/tuber initiation). Apply once or twice mid-season (e.g., at hilling and again 4–6 weeks later during bulking). Avoid frequent/high N boosts—excess reduces volatiles and starch. Monitor: If tops are overly vigorous/dark green, skip or halve the dose. Earlies need minimal; maincrops benefit from one focused top-dress for bulking/flavor.

• Rows/Beds: 80–120 grams per metre of row. Spread evenly along the row/base of plants (10–15 cm from stems), lightly scratch in during hilling, and water thoroughly. This adds controlled K for tuber quality and aroma precursors.
• Single Plants/Hills (In-Ground or Raised Beds): 1–2 tablespoons (15–30 grams) per plant/hill. Apply in a ring around the base (10–15 cm from stem) and incorporate lightly during earthing up.
• Potted Plants: 0.5–1 teaspoon (2.5 - 5 grams) per 10cm of volme). Top-dress around the base, scratch lightly if possible, and water well to distribute. Lower rates prevent overload in pots, preserving balanced flavour development.

General Tips for Maximum Flavour:

• Mix fertilizer 1:1 with compost before applying—this enhances microbial activity (EM/biochar synergy), improves nutrient availability, and supports diverse rhizosphere communities linked to better starch/volatiles.
• Prioritize potassium-rich soil conditions (positive correlation with starch and flavor scores in trials); avoid high total N buildup.
• Harvest at maturity for peak flavor—over-mature or stressed tubers lose volatiles.
• Store cool/dark post-harvest to preserve aroma compounds.

Supporting Research on Organic Fertilisation for Flavour and Yield in Potatoes

• Studies (2020–2024), including field trials on potato varieties like Impala: Organic fertilizers significantly enhanced tuber yield (up to 41.9 t/ha), dry matter, starch content (15–30% increases), and reduced residual nitrates (below permissible norms) compared to mineral controls, with organic systems outperforming for functional/nutritional quality.
• Organic fertilization trials (2023–2024): Combinations with biofertilizers boosted yield (up to 104% over controls), tuber size/quality, starch (79% increases), sugars, and enzyme activities, with balanced low-N, higher P/K organics like 3-5-7 equivalents improving flavour and texture over high-N synthetics.
• Global meta-analysis and multi-site studies (2023): NPK + organic sources improved potato yield by ~31% and nutritional quality (starch, vitamin C, dry matter) by ~12–30% on average, with potatoes highly responsive; ratios emphasizing P/K (e.g., 1:0.25:1.44 requirements) support tuber bulking, flavour, and reduced nitrates.

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 potatoes, particularly in organic or regenerative systems.

• Mycorrhizal Fungi: Inoculate tubers or apply at planting (slurry method recommended). AMF extend root systems for better uptake, increasing tuber yield (up to 20–50%), starch/dry matter, sugars, and stress tolerance. Meta-analyses confirm higher nutritional quality and blight resistance.
• Seaweed Extract: Apply as foliar spray every 7–14 days. Acts as biostimulant with hormones and bioactives; research shows boosts in yield (up to 65% under stress), tuber size, vitamin C, and flavour profile, plus enhanced nutrient efficiency.
• Liquid Calcium Sulphate (Gypsum): Apply as soil drench every 2–4 weeks. Provides available calcium without pH change; trials link to reduced hollow heart/scab, firmer tubers, better shelf life, and consistent quality in variable conditions.
• Additional Humic Acid (or Humic/Fulvic Acids): Use as soil drench every 2–4 weeks. Chelates nutrients, stimulates roots/microbes; studies report 15–30% higher starch/sugars, antioxidants, and flavour/nutritional value.
• Cover Crops (e.g., Rye, Radish, or Legume Mixes): Sow in autumn/winter, incorporate as green manure in spring. Builds organic matter, suppresses diseases; long-term trials show enhanced potato yields, soil health, and reduced issues.

These amendments align with regenerative principles, reducing reliance on inputs while maximising the potential of your 3-5-7 fertiliser. Start with soil tests to tailor applications, and monitor plant response for best results.

Dr Forest Organic Potato Fertiliser 3-5-7 is an evidence-backed, flavour-focused organic potato fertiliser designed for maximum taste and yield.