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Dr Forest

All-Purpose Fertiliser UK | Dr Forest | 6-6-6 NPK

All-Purpose Fertiliser UK | Dr Forest | 6-6-6 NPK

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All-Purpose Fertiliser UK — 6-6-6 NPK, Made with Certified Organic Ingredients

6-6-6 NPK 16 Ingredients Dual Fast & Slow Release British Ingredients No Slaughterhouse Waste Compostable Packaging

Dr Forest All-Purpose Fertiliser is a slow-release granular fertiliser made with certified organic ingredients — developed by growers, validated by science — for the full range of garden plants — vegetables, soft fruit, flowers, shrubs, perennials and ornamentals. Formulated and handcrafted in the UK, the balanced 6-6-6 NPK formula is calibrated from published plant nutrition research to deliver what every garden plant genuinely needs. Most all-purpose fertilisers are a compromise, a single formula stretched awkwardly across every plant in the garden. Dr Forest All-Purpose was built differently.

Equal N, P and K is not a marketing shorthand — it reflects the nutritional reality of the widest possible range of garden plants in active growth. As a slow release fertiliser for vegetables, flowers and fruit, sixteen synergistic ingredients deliver both an immediate mineral fraction that feeds within days and a slow-release organic fraction that builds soil biology and feeds for weeks. Suitable as a vegetable garden fertiliser, flower bed fertiliser, and general garden feed across beds, borders, containers and raised beds.

Multiple Sources Per Nutrient — Why It Matters

Most organic fertilisers rely on a single source for each nutrient — which means one release speed, one availability window, and a long gap before the next application can bridge it. This formula is built differently. Nitrogen comes from three sources at different speeds: alfalfa meal releases quickly in the first two to three weeks, rapeseed meal follows over six to eight weeks as it decomposes, and the plant extract nitrogen source provides a sustained controlled-release background supply across the whole growing season. Potassium is available immediately from Sulphate of Potash and then replenished over 50–60 days by Yorkshire Polyhalite as its crystal structure slowly dissolves in soil moisture. Magnesium is available within days from micronised magnesium mineral for rapid correction, and then maintained continuously through the season by the Mg fraction in polyhalite. Sulphur arrives from three directions simultaneously: immediately from SOP, through medium-term breakdown of rapeseed meal, and over the long term from polyhalite's 48% SO₃ content. Every key nutrient has at least two sources operating at different release speeds. The result is steady, unbroken nutrition through the whole season rather than a flush of availability followed by a slow decline — and that continuity is what separates consistently healthy, productive plants from ones that grow in waves.

Why 6-6-6 and not a higher-N or higher-K formula?

A higher-nitrogen formula drives rapid leafy growth — ideal for lawns and brassicas, but actively counterproductive for flowering plants, fruiting crops and established shrubs, where excess N suppresses flowering and delays ripening. A higher-K formula biases the product towards bloom performance. The balanced 6-6-6 ratio reflects the consensus position of Marschner (2012) and Barker & Pilbeam (2015): a 1:1:1 NPK ratio as the nutritional baseline for generalised garden use, supplemented by the secondary and trace minerals most British soils are demonstrably deficient in.

What it does across your whole garden

Healthy Leaves & Structure
Balanced nitrogen supports chlorophyll synthesis and steady structural growth without forcing excessive soft, disease-prone tissue
Root Development
Balanced phosphorus drives ATP synthesis and root tip cell division — critical during establishment and after transplanting
Fruit, Flower & Resilience
Potassium activates stomatal control and sugar transport — plants flower, fruit and weather summer heat more effectively
Disease Resistance
Silica, calcium and worm casting biology build both physical cell-wall defences and systemic acquired resistance pathways
Living Soil
Biochar, humic acid and herbal mixture feed soil microbial life, mycorrhizal networks and phosphorus-solubilising bacteria
Fast & Lasting Action
Sulphate-form minerals act within days; slow-release organic fractions and polyhalite extend the feeding window for 6–8 weeks

Why Dry Amendments Beat Liquid Feeds

Liquid feeds — including most branded tomato feeds, seaweed tonics and NPK solutions — deliver nutrients in water-soluble form that roots can absorb almost immediately. That sounds like an advantage. In practice it creates a fundamental problem: the plant gets what it needs for roughly 24–72 hours, and then the nutrient window closes. Miss a watering, go away for a week, or have a cool fortnight that slows plant metabolism, and the plant is unfed. Liquid feeding is high-maintenance by design — it was developed for commercial growers who irrigate on precise schedules, not for gardens and allotments where conditions vary daily.

Dry granular amendments work differently. Applied once, they sit in the root zone and release nutrients continuously as soil moisture and microbial activity break them down. The plant draws on that reservoir as and when it needs it — faster during hot, actively growing periods; slower in cooler or drier conditions. The release rate self-regulates to match plant demand. One application every four to six weeks does the work of dozens of liquid feeds, without the salt build-up that water-soluble feeds leave behind in containers and compost.

There is also a soil biology dimension that liquid feeds cannot address at all. Dry organic amendments feed the microbial community as they decompose — bacteria, fungi, actinomycetes and nematodes that in turn mineralise nutrients, build soil structure, suppress pathogens and extend root reach. A plant fed exclusively on liquid feeds may look well-fed, but the soil it grows in gets progressively poorer. A plant fed with dry organic amendments grows in soil that gets progressively richer.

Why Organic Ingredients Beat Mineral Fertilisers

Mineral fertilisers — including synthetic NPK granules, sulphate of ammonia, and most supermarket plant foods — supply nutrients as water-soluble salts. They are effective in the short term, and a plant cannot tell the difference between a nitrogen atom from urea and one from rapeseed meal. But the effects on the growing environment are very different.

Soluble mineral salts accumulate in soil over time, raising electrical conductivity (EC) and creating osmotic stress at the root surface. In containers this is measured as salt burn — wilting, tip scorch, and eventually root death despite adequate watering. In open ground it manifests more slowly as declining soil structure, reduced earthworm populations and falling microbial diversity. DEFRA's Countryside Survey and a 2024 ScienceDirect meta-analysis both document this decline across conventionally fertilised soils.

Organic ingredients carry no soluble salt load. They release nutrients through biological decomposition — a process that simultaneously feeds the soil food web rather than bypassing it. Every gram of rapeseed meal, alfalfa or worm castings that breaks down supports a population of bacteria and fungi that in turn improve nutrient availability, soil aggregation and water retention. The cumulative effect compounds year on year: soil fed with organic amendments becomes more fertile over time, not less. That is not a marketing claim — it is the basic mechanism of how soil builds up in the absence of tillage and synthetic inputs, documented extensively in long-term soil trials going back to the Rothamsted experiments of the 1840s.

This formula uses sulphate-form minerals (SOP, polyhalite, micronised magnesium) selectively for specific, justified reasons — speed of availability and mineral density — but the backbone of the formulation is organic. The minerals serve the biology; the biology feeds the plant.

Made by growers, backed by science. Named after Dr Forrest — an NHS GP and passionate kitchen gardener. Every Dr Forest product is developed through hands-on growing trials and published plant nutrition research. No bone meal. No blood. No feather meal. Just plants, minerals, and science.

Made by growers, backed by science. Named after Dr Forrest — an NHS GP and passionate kitchen gardener. Every Dr Forest product is developed through hands-on growing trials and published plant nutrition research. No bone meal. No blood. No feather meal. Just plants, minerals, and science.

 

 

All 16 Ingredients — What They Do and Why

Every ingredient is in this formula for a specific, research-backed reason. Nothing is filler.

Sulphate of Potash
🪨 Mineral · Immediate release

Primary potassium carrier. Chloride-free — muriate of potash causes tip burn and osmotic stress across a wide range of vegetables and ornamentals. SOP delivers K and S within days of application, activating stomatal regulation, sugar transport and cell-wall synthesis immediately across the full plant range.
Römheld & Kirkby, 2010 — K functions in higher plants
Micronised Magnesium Mineral
🇬🇧 British · Fast release

Mg is the central atom in every chlorophyll molecule and an essential enzyme cofactor in ATP synthesis. Micronisation increases surface area and availability dramatically versus standard mineral grades. UK soils are chronically Mg-deficient (DEFRA Countryside Survey, 2016) — deficiency is visible as interveinal yellowing in virtually every garden plant type.
DEFRA Countryside Survey · Marschner, 2012
Nitrogen Plant Extract
🌿 Plant-derived · Controlled release

Concentrated plant-derived nitrogen providing the steady, controlled release required for structural amino acid synthesis, chlorophyll production and consistent vegetative growth. Plant-derived N mineralises more slowly than inorganic forms, avoiding the flush-and-crash growth cycle that weakens plant tissue and increases pest susceptibility.
Marschner, 2012 — nitrogen and plant growth regulation
Phosphorous Plant Meal
🌿 Plant-based · Moderate release

P is essential for ATP synthesis, root cell division, seed and fruit set, and DNA replication. Included at 6% to support the full plant lifecycle — from root establishment to flowering and fruiting — without over-saturating the rhizosphere in ways that create Zn and Fe antagonism or suppress mycorrhizal colonisation.
Whipker et al., NC State · Brundrett, 2009
Rapeseed Meal
🇬🇧 Cold-pressed British

A British-grown slow-release nitrogen source that feeds soil microbial communities as it breaks down, sustaining background N supply for 6–8 weeks. Glucosinolate breakdown products also demonstrate biopesticidal activity against soil nematodes and Pythium — protecting root systems across vegetables and ornamentals alike.
Mattner et al., 2008 — glucosinolates and Pythium suppression
Scottish Seaweed Meal
🇬🇧 Hand-harvested Scotland

Ascophyllum nodosum provides cytokinins that delay leaf senescence, betaines that improve osmotic adjustment under drought, and mannitol that acts as a carbon source for beneficial rhizobacteria. Across 23 independent trials, seaweed meal produced a consistent 10–15% improvement in stress tolerance and crop quality across diverse plant types.
Craigie, 2011 — seaweed biostimulants across crop systems
Seaweed Extract
🌿 Cold-process extract

Cold-process liquid extract delivers bioactive auxins, cytokinins and alginic acid immediately available at the root surface. Auxin fractions stimulate lateral root initiation within the first week, increasing nutrient and water absorption capacity — particularly valuable for newly transplanted specimens across any plant category.
Stirk & van Staden, 2006 — auxins and lateral root initiation
Alfalfa Meal
🌿 Plant-based

Contains triacontanol, a natural growth regulator shown to increase chlorophyll content by 15–20% and accelerate meristematic cell division. Provides a broad secondary nutrient profile including Fe, Zn and B and acts as a prebiotic for beneficial rhizobacteria — supporting soil food web health across all planting styles.
Multiple trials — triacontanol and chlorophyll enhancement
British Biochar
🇬🇧 British agricultural by-product

Creates a permanent, porous mineral scaffold in the rhizosphere that retains water and nutrients between waterings. Biochar application increased plant-available K by 18–35% under leaching conditions — critical in UK summer rainfall patterns. Particularly valuable in sandy soils, pots and raised beds where nutrient loss through drainage is highest.
Lehmann et al., 2011 — biochar and K retention
Humic Acid
🌿 Mineral organic

Chelates micronutrients — particularly iron and manganese — maintaining them in plant-available form across a wide range of soil pH levels. Increases root proton pump activity and overall nutrient uptake efficiency. Critically, humic acid actively builds long-term soil health: research shows it increases total soil bacterial biomass by 30–60% and stimulates mycorrhizal fungal colonisation by up to 25–40%, creating a progressively richer, more biologically active rhizosphere with every application. This cumulative biological improvement is one of the most important differences between a fertiliser that feeds plants and one that builds the soil.
Nardi et al., 2009 · Zandonadi et al., 2010 · Muscolo et al., 2013
Dried Worm Castings
🌿 Vermicompost · Slow release

Worm castings are among the most biologically active soil amendments available — rich in beneficial bacteria, actinomycetes, fungal hyphae and plant growth-promoting rhizobacteria. They supply a broad, gentle NPK profile alongside water-soluble humates, enzymes and plant hormones that accelerate root development and nutrient uptake. Castings also improve soil structure and water-holding capacity, with research showing increased germination rates and seedling vigour across a wide range of plant types.
Arancon et al., 2006 — vermicompost and plant growth promotion
Silica Meal
🪨 Mineral

Strengthens epidermal cell walls, creating a physical barrier against aphid, thrip and fungal penetration. Si application reduces thrip damage by up to 40% in ornamentals and improves stem rigidity across vegetables. Silicon is not found in most garden soils at sufficient concentrations — it must be supplied, and most fertilisers omit it entirely.
Epstein, 1994 — silicon anomaly in plant biology
Clay Minerals
🇬🇧 British

Montmorillonite and illite clays carry high cation exchange capacity (CEC), acting as ionic reservoirs that bind and slowly release K, Ca and Mg between waterings. Prevents the flush-and-starve nutrient cycle that is common in peat, coir and sandy-loam substrates. Particularly beneficial in open ground where nutrient leaching under British rainfall is significant.
Barker & Pilbeam, 2015 — CEC in garden substrates
Volcanic Rock Dust
🪨 Basaltic mineral

Provides a slow-release source of 60+ trace and ultra-trace minerals including boron, molybdenum and cobalt that are absent from most garden soils yet critical to enzyme function. Boron is essential for pollen tube germination, calcium uptake and cell division. Rock dust also stimulates mycorrhizal colonisation by providing mineral weathering substrates that fungi require.
Barker & Pilbeam, 2015 — trace minerals in horticulture
Yorkshire Polyhalite
🇬🇧 North Yorkshire

A slow-release secondary reservoir of K, Ca, Mg and S that extends the fertiliser feeding window well beyond the fast-release mineral fraction. Mined exclusively in North Yorkshire from the world's largest known polyhalite deposit. Provides a sustained background supply of four macro and secondary nutrients simultaneously — without the release lag drawbacks of a polyhalite-only product.
ICL Fertilizers — Polysulphate multi-nutrient release kinetics
Herbal Mixture
🌿 Comfrey · Nettle · Yarrow · Chamomile

A traditional British fertility blend validated by modern soil science. Comfrey provides exceptional concentrations of K; nettle supplies Fe and silica; yarrow promotes phosphorus-solubilising bacteria that unlock soil P reserves; chamomile releases Ca and supports beneficial rhizobacteria colonisation. A broad-spectrum biological booster for any garden system.
Zaller & Kopke, 2004 — herbal preparations and rhizobacteria

 

 

 

 

Directions for Use

Dosages are calibrated for a 6-6-6 NPK formulation across general garden applications. All g/m² rates assume even surface incorporation to 2–3cm depth. For new beds, borders or containers being set up for the first time, apply at double the standard rate as an initial base charge and work into the full soil depth before planting.

How to Apply

1
Water first
Ensure soil or compost is moist before applying. Never apply to bone-dry soil — the mineral fraction requires moisture to dissolve and reach the root zone effectively.
2
Sprinkle evenly over the root zone
For beds and borders, distribute evenly across the surface over the full root area — not just at the stem base. For containers, sprinkle across the entire compost surface. Avoid direct contact with leaves and stems.
3
Lightly fork in
Gently incorporate into the top 2–3cm of soil or compost. In pots this can be done with a finger or small hand fork. In open ground, a border fork or hoe is ideal. Avoid deep incorporation — the biology is in the top layer.
4
Water in thoroughly
Water within 24 hours of application. In containers, water until it runs freely from the base to ensure even distribution through the root zone. In open ground, apply before rain when possible.

Vegetables & Salads

Plant Feeder Rate per m² Frequency
Tomatoes Heavy 70–80g Every 4 weeks
Courgettes & Squash Heavy 70–80g Every 4 weeks
Peppers & Chillies Heavy 65–75g Every 4 weeks
Brassicas (cabbage, kale, broccoli) Heavy 70–80g Every 5 weeks
Runner & French Beans Medium 50–60g Every 5–6 weeks
Peas Light 35–45g Every 6 weeks
Beetroot & Chard Medium 50–60g Every 5 weeks
Leeks & Onions Medium 50–60g Every 5–6 weeks
Salad Leaves & Lettuce Light 35–40g Every 6–8 weeks
Potatoes Heavy 70–80g At planting + once mid-season

Soft Fruit

Plant Rate per m² Timing
Strawberries 55–65g March and after first flush
Raspberries 60–70g March and June
Blackcurrants & Redcurrants 65–75g March and June
Gooseberries 60–70g March only
Blueberries 50–60g March and June (acidify soil separately if needed)

Shrubs, Perennials & Climbers

Plant Rate per m² Timing
Roses 70–80g March and June
Hydrangea 60–70g March and June
Clematis 60g March and June
Dahlias 70–80g At planting, then every 5–6 weeks
Hardy Geraniums (Cranesbill) 50g March and post-flower cut-back
Phlox (border) 55g March and June
Hemerocallis (Daylily) 55g Early spring + post-flower
Lavender 30–35g March only (one application)
Sweet Peas 50g At planting + every 6 weeks

Containers & Pots

Apply to moist compost, lightly fork into top 2cm, water thoroughly after application.

Container Rate Frequency
Small pot up to 5L 12–15g Every 6 weeks
Medium pot 5–10L 20–25g Every 5–6 weeks
Large pot 10–20L 30–40g Every 4–5 weeks
Grow bag (standard 40–50L) 30–35g per bag Every 4 weeks
Raised bed per m² 55–65g Every 5 weeks
Window box 60cm 20–25g Every 5 weeks

Good to Know

Season
Late March to early September for vegetables and annual crops. Shrubs, perennials and fruit bushes can be fed through to end of September. Soil must be above 8°C for organic N fractions to mineralise.
With liquid feeds?
Compatible with seaweed or comfrey tea. Do not combine with high-N liquid feeds in the same week.
Seedlings
Do not apply to plants under 4 weeks old or seedlings with fewer than 4 true leaves. Wait until established.
Over-application signs
Lush dark foliage, soft growth, leaf margin scorch. Reduce rate by 25% and water the root zone heavily.
Safe for
Children, pets, bees and pollinators once watered in. No toxic compounds or synthetic chemicals.
Shelf life
3 years from manufacture when stored cool, dry and sealed.

 

 

The Science Behind the Formula

Dr Forest All-Purpose is not a reformulation of a commodity fertiliser. Every NPK ratio, every ingredient, every inclusion rate was derived from peer-reviewed research in plant nutrition. Here is the evidence.

Why balanced 1:1:1 and not a high-nitrogen formula?

High-nitrogen all-purpose fertilisers originate from market garden and agricultural research focused on maximising bulk leafy yield. For the broadest possible range of garden plants — including fruiting crops, flowering shrubs, perennials and ornamentals — excess nitrogen actively suppresses flowering, delays fruit ripening, and promotes the soft, disease-prone tissue that invites aphid colonisation and fungal infection. The balanced 6-6-6 formula reflects the consensus nutritional baseline identified across Marschner (2012), Barker & Pilbeam (2015) and the MSU Floriculture Nutrition Trial Series for diverse plant communities.

The Three-Nutrient Balance and Why It Works Across All Plants

A 1:1:1 NPK ratio is not a compromise — it is the nutritional architecture that mirrors what the widest range of garden plants actually consume. Tissue analysis data collated by Marschner (2012) across over 200 crop and ornamental species shows that N, P and K are withdrawn from the soil in broadly equal proportions during balanced vegetative and reproductive growth phases. The 6-6-6 ratio satisfies all three macro demands simultaneously without forcing any single nutrient into excess.

Nitrogen (6%)
Amino acid and chlorophyll synthesis. Dual-source delivery: fast plant-extract N for immediate uptake, slow rapeseed N for 6–8 week sustained supply.
Phosphorus (6%)
ATP synthesis, root tip cell division, seed and fruit development. Phosphorous Plant Meal mineralises moderately — supporting the full growth cycle without antagonising Zn and Fe.
Potassium (6%)
Stomatal control, sugar transport, cell-wall synthesis, anthocyanin production and enzyme activation. Chloride-free SOP ensures immediate availability without the osmotic stress of muriate forms.
Calcium (4–5%)
Immobile in the phloem — must be continuously supplied. Ca competes with K at root channels; elevated Ca prevents K-induced deficiency in heavy-feeding summer crops.
Magnesium (1.5–2%)
Central chlorophyll atom and ATP cofactor. UK soils are chronically deficient (DEFRA, 2016). Micronised mineral corrects deficiency immediately across the whole garden.
Sulphur (via SOP & polyhalite)
Essential for cysteine, methionine and glucosinolate synthesis. UK soils have lost 70–80% of atmospheric S deposition since 1980 (DEFRA). Most garden fertilisers omit it entirely.

Dual-Speed Release: Why Both Matter

A common flaw in organic granular fertilisers is that they either release too slowly to feed plants that need nutrients now, or too quickly — causing a flush of growth followed by starvation. Dr Forest All-Purpose uses a deliberate dual-layer approach: sulphate-form minerals (SOP, micronised Mg) dissolve within days of application, providing an immediate nutritional response. The organic fractions — rapeseed meal, plant extract N, herbal mixture — mineralise over 6–8 weeks via microbial protease activity, providing sustained background nutrition. Yorkshire Polyhalite acts as a third, long-tail reservoir of K, Ca, Mg and S at the back end of the cycle.

The Soil Biology Layer

Unlike synthetic fertilisers, which bypass soil biology entirely, Dr Forest All-Purpose actively feeds and supports the organisms that make nutrients available in the first place. Biochar creates a permanent microbial habitat with high surface area and water retention. Humic acid chelates micronutrients and stimulates root proton pump activity. Dried worm castings introduce a dense community of plant growth-promoting rhizobacteria, enzymes and water-soluble humates that accelerate nutrient cycling. The herbal mixture provides prebiotic carbon for rhizobacteria. Seaweed extracts supply cytokinins that delay senescence and auxins that drive lateral root proliferation. The result is a fertiliser that improves soil structure and biological activity cumulatively with each application — not one that mines and degrades it.

Peer-Reviewed References

  • Adams, C.R. (2004). Principles of Horticulture, 4th ed. Butterworth-Heinemann.
  • Arancon, N.Q. et al. (2006). Effects of humic acids from vermicomposts on plant growth. European Journal of Soil Biology, 42(Suppl. 1), S65–S72.
  • Barker, A.V. & Pilbeam, D.J. eds. (2015). Handbook of Plant Nutrition, 2nd ed. CRC Press.
  • Brundrett, M.C. (2009). Mycorrhizal associations and other means of nutrition of vascular plants. Plant and Soil, 320(1–2), 37–77.
  • Craigie, J.S. (2011). Seaweed extract stimuli in plant science and agriculture. Journal of Applied Phycology, 23(3), 371–393.
  • DEFRA / CEH (2016). Countryside Survey: Soil Chemical Properties Technical Report.
  • Epstein, E. (1994). The anomaly of silicon in plant biology. PNAS, 91(1), 11–17.
  • ICL Fertilizers. Polysulphate Multi-Nutrient Release Kinetics. Technical Bulletin.
  • Lehmann, J. et al. (2011). Biochar effects on soil biota — a review. Soil Biology and Biochemistry, 43(9), 1812–1836.
  • Marschner, P. ed. (2012). Marschner's Mineral Nutrition of Higher Plants, 3rd ed. Academic Press.
  • Mattner, S.W. et al. (2008). Factors influencing efficacy of brassica incorporation. Applied Soil Ecology, 40(1), 137–147.
  • Nardi, S. et al. (2009). Physiological effects of humic substances on higher plants. Soil Biology and Biochemistry, 34(11), 1527–1536.
  • Römheld, V. & Kirkby, E.A. (2010). Research on potassium in agriculture. Plant and Soil, 335(1–2), 155–180.
  • Stirk, W.A. & van Staden, J. (2006). Seaweed products as biostimulants in agriculture. Journal of Applied Phycology, 18(3–5), 281–285.
  • Whipker, B.E. et al. NC State University Floriculture Research — Fertilizer Rate Trials. NC State Extension.
  • Zaller, J.G. & Kopke, U. (2004). Effects of biodynamic farmyard manure on soil biological properties. Biology and Fertility of Soils, 40(4), 222–229.

 

 

 

 

Frequently Asked Questions

Common questions about using Dr Forest All-Purpose Fertiliser.

Begin once soil temperature is consistently above 8°C — typically late March in the north of England, mid-March in southern areas. The organic nitrogen fractions in this formula require active soil microbial activity to mineralise. Applying to cold soil means nutrients sit inert and unavailable until temperatures rise, so timing to soil warmth rather than calendar date gives better results. If in doubt, squeeze a handful of soil: it should be crumbly and smell earthy, not cold and compacted.
The general guide is every four to six weeks, calibrated by how heavy a feeder the plant is. Heavy feeders like tomatoes, courgettes and brassicas benefit from every four weeks. Medium feeders like beetroot, leeks and soft fruit are typically every five to six weeks. Light feeders like peas, salad leaves and lavender need less — every six to eight weeks or a single spring application. The slow-release organic fractions in the formula feed for six to eight weeks, so there is no benefit to applying more frequently than four weeks for even the hungriest plants.
Yes — that is the purpose of the balanced 6-6-6 formula. Rather than keeping separate feeds for vegetables, flowers, fruit bushes and ornamentals, this product is calibrated to satisfy the broad nutritional baseline of all of them in active growth. Where growers want to push performance further in specific crops — tomatoes during fruiting, for example, or roses during the main flush — it can be supplemented with a crop-specific product at those moments. But for the vast majority of garden situations, a single application of this product across everything is both practical and effective.
At the recommended rates, no. Organic granular fertilisers do not carry the same salt burn risk as water-soluble synthetic feeds because nutrients are released through microbial breakdown rather than immediately dissolving. The most common cause of issues is applying to dry soil or allowing granules to sit in contact with stems and leaves — both of which are avoided by following the application steps. If you significantly exceed the stated rates, the elevated mineral fraction from SOP and polyhalite can cause root zone concentration issues, so stick within the recommended range, particularly in containers where there is no soil buffer to dilute excess.
Yes. Container rates are lower per litre of compost than open ground rates because there is no soil buffer — nutrients are concentrated in a fixed volume of media. Use the container rate table rather than the per-m² rates when feeding pots, grow bags or raised beds with a depth under 30cm. Always water thoroughly after application to begin distributing the mineral fraction through the root zone. In containers with drainage, watering until it runs from the base ensures even distribution.
Do not apply to seedlings under four weeks old or plants with fewer than four true leaves. Young seedlings have undeveloped root systems and limited capacity to buffer even mild nutrient concentrations. Wait until plants are established and actively growing before applying. For potting-on into compost, the granules can be mixed into the compost at the base charge rate and the seedlings moved in once their roots are large enough to grow through rather than sit on top of the fertiliser layer.
Growmore (7-7-7) is a fully synthetic water-soluble granular feed. It delivers nitrogen, phosphorus and potassium quickly but does nothing for soil biology, contains no secondary nutrients, no trace minerals, and degrades soil structure over time through salt accumulation. Fish, blood and bone is a three-ingredient organic blend providing a single release speed per nutrient with no soil biology support, no potassium source beyond what is incidental in the meal, and no Ca, Mg or S. Dr Forest All-Purpose uses 16 ingredients delivering multiple release speeds per nutrient, Yorkshire polyhalite as a four-nutrient secondary mineral, humic acid for chelation and CEC, biochar for water and nutrient retention, seaweed for biostimulant activity, and dried worm castings for soil microbial enrichment and plant growth promotion. Every additional ingredient has a specific, research-backed function.
Dr Forest products use no slaughterhouse by-products. This is a deliberate formulation choice, not a constraint. Phosphorus comes from a plant-derived meal source rather than bone; nitrogen comes from plant-derived fractions rather than dried blood. This makes the products suitable for growers who prefer to avoid all animal slaughter by-products in their garden, while maintaining full nutritional performance.
It is compatible with seaweed teas, comfrey teas and similar low-nutrient biostimulant liquids. Do not combine with high-nitrogen liquid feeds like tomato feed or liquid grow in the same week — the combined nitrogen input will push total N beyond what the plant can use efficiently, risking soft growth and increased pest susceptibility. If using a specialist liquid feed during peak demand periods, reduce or skip the granular application that month.
Our larger pack sizes are supplied in kraft paper bags that are home-compostable and recyclable through standard paper recycling streams. Please check the packaging on your specific size at point of purchase for the most accurate recycling information.

 

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