Dr Forest
Organic All Purpose Fertiliser 4-4-4
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- ✓Made with organic ingredients
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All Purpose 4-4-4 — a balanced organic fertiliser for the whole garden
All Purpose 4-4-4 is a balanced organic fertiliser that feeds almost everything in the garden from a single bag — vegetables, fruit, flowers, roses, herbs and container plants. An even ratio of nitrogen, phosphorus and potash covers leaf, root and flower together, released slowly through soil biology so there are no salt spikes and no scorched roots. Dr Forest blends it by hand in Stockport from ten organic inputs, with slow-release phosphorus and calcium from bone meal and natural biostimulants from Scottish seaweed and alfalfa.
It takes over from our Veg 4-4-4. Growers kept using that right across the plot rather than only for leafy growth, so we reformulated it as a true all-purpose feed — the same balanced 4-4-4 ratio, but a new recipe with some different ingredients chosen to suit the whole garden. The even ratio covers the majority of what UK gardeners grow, and the feeding guide simply matches the rate to how hungry each plant is.
It is a granular dry amendment — sprinkle it on or mix it in, with no dissolving, no measuring pH and no weekly liquid feeding. Because the nutrients come from organic meals and slow-release minerals rather than soluble salts, soil microbes release them at the pace the plant demands, building soil health rather than degrading it. Made with organic ingredients, compostable packaging, handcrafted in small batches.
One fertiliser, the whole garden
- Vegetable beds and allotments — feeds brassicas, roots, legumes, alliums and salad crops, with calcium and magnesium most veg feeds leave out.
- Fruiting crops — tomatoes, cucumbers, courgettes, peppers, chillies, strawberries, currants and gooseberries; balanced NPK supports growth then flower and fruit set.
- Roses, dahlias and flower borders — steady feeding for strong stems, healthy foliage and repeat blooms.
- Pots, containers and hanging baskets — mix in at potting, then top dress as the compost runs down.
- Herbs and leafy greens — gentle, sustained nitrogen for lettuce, spinach, chard, basil and parsley.
- Shrubs, evergreens, hedging and trees — a balanced spring and summer feed for box, yew, laurel, privet, conifers, acers, hydrangeas, ferns and ornamental grasses that have no crop-specific feed of their own.
- No-dig and living-soil plots — feeds the soil food web directly; seaweed, humic acid and biochar build fertility season after season.
Organic dry amendment vs synthetic soluble feed
Dr Forest All Purpose 4-4-4
- 10 organic inputs — several sources per nutrient, for even release
- Feeds through microbial breakdown at the rate plants demand
- Calcium, magnesium and sulphur built in
- Builds soil biology and structure with every application
- No salt build-up; the soil improves rather than degrades
Typical synthetic soluble feed
- Two or three mineral salts, quickly used up
- A spike of availability, then run-off
- Usually no calcium and few trace minerals
- Bypasses the soil food web entirely
- Salt accumulation can harm roots and soil life over time
Handcrafted in small batches in Stockport, Greater Manchester, using British ingredients where possible, including Scottish seaweed. Made with organic ingredients, with no synthetic chemistry. Made by Growers. Backed by Science.
Ten organic inputs, each with a job to do
This is a multi-input blend, not a two-part salt feed. Every ingredient earns its place — a primary nutrient, a secondary nutrient, or a biological function. Shares below are the proportion of the mix.
Alfalfa meal
The largest single input, and the carbon backbone of the blend. At a third of the mix, alfalfa is the main source of plant-based organic matter — the carbon that soil microbes feed on and steadily turn into humus, building soil structure, water-holding and long-term fertility. It also carries triacontanol, a natural growth promoter shown to lift chlorophyll and photosynthesis, along with nitrogen, potassium and amino acids that feed soil bacteria. It breaks down at a medium pace, bridging the fast and slow nitrogen sources.
Bone meal
The main phosphorus and calcium source — around 18% phosphorus (P₂O₅) with a large calcium fraction, released slowly as soil acids and microbes work on it. Phosphorus drives roots, flowering and fruit set; calcium builds firm cell walls. Availability is best in slightly acidic to neutral soil. (Because it contains bone meal, this blend is not suitable for vegan gardening.)
Nitrogen plant extract
A concentrated plant nitrogen at around 13% N, derived from molasses and rich in amino acids — the early drive of the blend. Amino-acid nitrogen is taken up efficiently and feeds through microbial mineralisation rather than as a soluble salt, so there is no ammonia volatilisation and no EC spike, just a steady release as the soil warms.
Flaxseed meal
Cold-pressed linseed meal adds a further slow-release nitrogen source plus organic matter and oils that feed the soil microbiome. It rounds out the nitrogen curve and improves the texture and workability of the blend in the soil.
Gypsum
Calcium sulphate — a pH-neutral source of calcium and sulphur. It adds calcium without shifting soil pH, supports cell-wall strength and fruit quality, and helps open up heavier soils.
Sulphate of potash
Chloride-free potassium (50% K₂O) with sulphur alongside. Potassium governs water movement, fruit and flower quality and disease resistance — the nutrient fruiting crops draw down hardest — and the sulphate form avoids the chloride that some crops dislike.
Kieserite
Magnesium sulphate — a steady source of magnesium and sulphur. Magnesium sits at the centre of every chlorophyll molecule, so it keeps foliage green; sulphur supports protein and amino-acid synthesis.
Scottish seaweed
Cold-water Ascophyllum nodosum from the Scottish coast. A biostimulant rather than a headline nutrient source, it supplies cytokinins, auxins, alginates and a spread of trace elements that prime the plant's own growth and stress responses.
Humic & fulvic acid
Humic acid raises the soil's cation exchange capacity and improves structure and root growth; fulvic acid is a low-molecular-weight chelator that binds micronutrients into forms roots can take up. A little goes a long way.
Fermented biochar
Pyrolysed carbon with a vast internal surface that houses beneficial microbes. Pre-fermented so it is biologically active from day one, it helps hold nutrients in the root zone and reduce leaching under heavy watering or rain.
Feeding guide: light, medium and heavy feeders
Soil mix (before planting): 5–10 g per litre of soil or compost, worked in thoroughly. Top dress (during growth): 2–4 g per litre of soil, scattered on the surface and watered in. As a guide, a level tablespoon holds roughly 12–15 g. Match the rate to how hungry the plant is, using the three groups below.
Plants are grouped by how much feeding they need. Light feeders — legumes, root crops and Mediterranean herbs — grow best in leaner soil and can run to leaf or fork if overfed. Heavy feeders — fruiting vegetables, brassicas and container plants — draw nutrients down fast and need topping up often. Medium feeders sit in between.
Light feeders — lean and steady
Fix their own nitrogen or store food in their roots, so too much feed brings leafy tops, forked roots or fewer flowers.
- Vegetables: peas, broad beans, runner beans, French beans, carrots, parsnips, beetroot, radishes, turnips, onions, garlic, shallots.
- Herbs: rosemary, thyme, sage, oregano, bay, lavender.
- Ornamentals & evergreens: established trees and shrubs, conifers and evergreens, hedging (box, yew, privet, laurel), topiary, acers, ferns, ornamental grasses, alpines, nasturtiums and wildflower areas.
Medium feeders — the everyday majority
Steady demand through the season, happy on a balanced feed.
- Vegetables: potatoes, sweetcorn, salad leaves, lettuce, spinach, chard, rocket, kale, leeks.
- Fruit: strawberries, raspberries, blackcurrants, redcurrants, gooseberries, blueberries (keep the soil acidic for these).
- Flowers & shrubs: hardy annuals, cosmos, sweet peas, sunflowers, geraniums, petunias, most herbaceous perennials and bedding, flowering shrubs (hydrangea, hebe, viburnum) and climbers (wisteria, honeysuckle, jasmine).
Heavy feeders — hungry and fast
High, sustained demand, especially in pots, grow bags and baskets where roots are confined and watering leaches nutrients away.
- Fruiting veg: tomatoes, cucumbers, courgettes, marrows, pumpkins, squash, peppers, chillies, aubergines.
- Brassicas: cabbage, cauliflower, broccoli, Brussels sprouts.
- Hungry crops & flowers: rhubarb, celery, roses, dahlias, chrysanthemums, clematis, hanging baskets and patio containers.
Outdoor beds, borders and allotments
Scatter evenly and work lightly into the top 5–10 cm. Lower end for light feeders and established beds, upper end for heavy feeders and new plantings. A handful is roughly 40–50 g.
Step by step
- Prepare the soil. For new plantings, mix All Purpose 4-4-4 into the compost or bed at 5–10 g per litre before planting.
- Match the rate to the plant. Light feeders at the lower end, heavy feeders at the upper end, using the three groups above.
- Water in. After a top dress, water well — moisture activates the soil biology that releases the nutrients.
- Watch the plant. When lower leaves fade from deep green to pale, or growth slows, it is time to top dress again.
- Repeat through the season. Keep to the frequency for the feeder group; ease off as crops finish or plants go dormant.
1. Overfeeding light feeders — beans and carrots want lean soil. 2. Underfeeding pots — confined roots and frequent watering empty a container fast. 3. Expecting an overnight response — this feeds over weeks, not hours. 4. Applying to bone-dry soil — always water in. 5. Feeding dormant plants in winter — wait until growth restarts in spring.
Pair with Sulphate of Potash for a potash lift on tomatoes, roses and fruit as they flower and set, and with Seaweed Plant Food for extra biostimulant during heat or transplant stress. For fruiting crops that want more phosphorus and potash later on, our Fruit & Vegetable Fertiliser 4-5-6 carries them through to harvest.
Keep the bag sealed in a cool, dry place. As a natural product it may vary slightly in colour and texture between batches, and the odd seed may sprout if left damp — neither affects performance. It contains bone meal, which some dogs find tempting, so store out of reach of children and pets.
Why a balanced 4-4-4 works across so many plants
Nitrogen builds leaves and stems, phosphorus drives roots and flower set, potassium governs water movement, fruit quality and disease resistance. Nearly every plant needs all three throughout its life; what changes between crops is the quantity, not the mix. A balanced 4-4-4 supplies the full range, and the feeding rate is matched to demand.
Because the nutrients are held in organic matter and slow-release minerals rather than soluble salts, soil microbes release them as the plant's roots call for them. That is why one bag suits a hungry courgette and a lean-feeding carrot: the plant and its root-zone biology set the pace.
Mechanisms of action
Five nitrogen sources, released steadily
An amino-acid nitrogen extract derived from molasses (13% N) gives the early drive, while alfalfa, flaxseed meal, bone meal and seaweed release nitrogen more slowly through microbial mineralisation (Cassity-Duffey et al., 2020). Staggered release means healthy growth without the soft, sappy, pest-prone tissue that a single hit of soluble nitrogen produces.
Slow-release phosphorus and calcium
Bone meal supplies phosphorus (around 18% P₂O₅) alongside a large dose of calcium, released as soil acids and microbes work on it. Phosphorus is the core of ATP, driving root development, cell division and flower and fruit set. Availability is highest in slightly acidic to neutral soil (Penn & Camberato, 2019).
Chloride-free potash
Sulphate of potash (50% K₂O) delivers potassium in a chloride-free form with sulphur alongside, topped up by potassium in alfalfa and seaweed. Sulphate-based potassium suits chloride-sensitive crops such as tomatoes, strawberries and potatoes.
Calcium, magnesium and sulphur built in
Gypsum (calcium sulphate) and kieserite (magnesium sulphate) supply the calcium, magnesium and sulphur most all-purpose feeds omit, with more calcium from the bone meal. Most liquid feeds contain no calcium at all — a key gap this blend closes. Magnesium sits at the centre of chlorophyll; sulphur drives protein synthesis.
Seaweed biostimulant
Scottish seaweed (Ascophyllum nodosum) supplies cytokinins, auxins, alginates and trace elements. Reviews of seaweed biostimulants report gains in growth, yield and crop quality across a range of crops (Khan et al., 2009; Ali et al., 2021).
Triacontanol from alfalfa
Alfalfa carries triacontanol, a natural plant growth regulator linked in the literature to higher chlorophyll content and photosynthetic rate (Naeem et al., 2012), on top of the nitrogen and amino acids it contributes.
Humic substances feed the biology
Humic and fulvic acids stimulate root growth and microbial activity and improve nutrient uptake (Nardi et al., 2002; Canellas & Olivares, 2014); they also raise the soil's cation exchange capacity. Fulvic acid chelates micronutrients into plant-available forms.
Biochar holds nutrients in place
Fermented biochar's vast internal surface provides habitat for soil microbes (Lehmann et al., 2011) and helps hold nutrients in the root zone, so less drains away after heavy watering or rain.
Alfalfa: the carbon backbone that builds soil
At a third of the blend, alfalfa is the main organic-carbon feedstock — the raw material soil microbes live on. As they consume it, part of that carbon is stabilised as soil organic matter, the humus fraction that holds water, resists compaction and stores nutrients on the soil's exchange sites. Feeding the soil organic carbon this way builds that fraction over repeated seasons, so fertility compounds rather than running down.
Organic versus synthetic — the evidence
Dry organic feeding builds soil rather than depleting it. A global meta-analysis found organic fertilisation raised plant biomass by 56% while maintaining plant diversity, where inorganic-only feeding raised biomass 42% but cut species richness by 18% (Shi et al., 2024). Organic feeding also tends to lower nitrate accumulation in leafy crops compared with synthetic nitrogen, and long-term trials such as Rothamsted's Park Grass show organic plots holding or improving while mineral-only plots decline.
Scientific references
- Khan, W. et al. (2009). Seaweed extracts as biostimulants of plant growth and development. Journal of Plant Growth Regulation, 28, 386–399.
- Ali, O., Ramsubhag, A. & Jayaraman, J. (2021). Biostimulant properties of seaweed extracts in plants: implications towards sustainable crop production. Plants, 10(3), 531.
- Naeem, M. et al. (2012). Triacontanol: a potent plant growth regulator in agriculture. Journal of Plant Interactions, 7(2), 129–142.
- Nardi, S., Pizzeghello, D., Muscolo, A. & Vianello, A. (2002). Physiological effects of humic substances on higher plants. Soil Biology & Biochemistry, 34, 1527–1536.
- Canellas, L. & Olivares, F. (2014). Physiological responses to humic substances as plant growth promoter. Chemical and Biological Technologies in Agriculture, 1, 3.
- Lehmann, J. et al. (2011). Biochar effects on soil biota — a review. Soil Biology & Biochemistry, 43(9), 1812–1836.
- Penn, C. & Camberato, J. (2019). A critical review on soil pH and phosphorus availability. Agriculture, 9(6), 120.
- Cassity-Duffey, K. et al. (2020). Nitrogen mineralisation from organic materials and fertilisers. Soil Science Society of America Journal, 84, 522–533.
- Shi, T.-S. et al. (2024). A global meta-analysis on the effects of organic and inorganic fertilization on grasslands and croplands. Nature Communications, 15, 3411.
Figures describe the published literature on these ingredient classes and are not product-specific yield guarantees.
All Purpose 4-4-4 — frequently asked questions
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