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Dr Forest

Living Soil Refills UK

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Living soil programme — sold separately

Living Soil Refills

Veg, Bloom, bone meal and micronised rock phosphate. Restock what you need.

Everything in the Dr Forest living soil programme, sold on its own. Restock the blend you have run out of, feed heavier for maximum yield, or re-charge a soil you are running for a second or third year. Choose your component and your size. New to the programme? Start with the complete Living Soil kit.

Veg — 3.5-0.4-2.8The growing-phase amendment. Nitrogen-led, with calcium and magnesium from day one.
Bloom — 1.9-0.4-3.6The flowering amendment. Nitrogen steps down, potash and calcium step up.
Bone meal — 3.5-18.5The phosphorus charge. Worked into the soil once, a week before planting. Adds a little nitrogen.
Micronised rock phosphate — 31% P₂O₅The plant-based phosphorus charge. Nitrogen-free, slower than bone meal and more dependent on an acidic soil.

Reusing your soil? This is what you need

Veg and Bloom at full strength, and only a third of the phosphorus charge — last year's phosphorus is still banked in the soil. Top the organic matter back up with compost and you are away.

You bought the soil once. You do not need to buy it again.

Feed the soil and the soil feeds the plant.

★★★★★ 5-star across all platforms · 4,300+ reviews. Handcrafted in small batches in Stockport, Greater Manchester, in compostable packaging. Made with organic ingredients, and safe around children, pets and wildlife.

Veg — 3.5-0.4-2.8

Thirteen inputs, nitrogen-led, with a carbon backbone of organic alfalfa meal and bokashi-fermented bran. Calcium and magnesium available from day one. Humic and fulvic acid at 1% each.

Analysis

N 3.5% · P₂O₅ 0.4% · K₂O 2.8% · CaO 2.9% · MgO 1.9% · SO₃ 8.1%

Alfalfa meal 37.5% · amino-acid nitrogen from molasses extract 17% · bokashi bran 8.5% · gypsum 7% · seaweed meal 6.5% · kieserite 6.5% · zeolite 5.85% · malted barley 4.5% · sulphate of potash 3% · biochar 1.5% · humic acid 1% · fulvic acid 1% · boron complexed with humic acid 0.15%

Bloom — 1.9-0.4-3.6

Nitrogen drops back; potash and calcium rise. Magnesium sits on its optimum — enough for the job, and no more. Too much magnesium suppresses reproductive growth without buying any quality, so it is held level rather than pushed.

Analysis

N 1.9% · P₂O₅ 0.4% · K₂O 3.6% · CaO 3.7% · MgO 1.7% · SO₃ 10.0%

Alfalfa meal 31% · zeolite 17.15% · gypsum 10% · bokashi bran 8% · seaweed meal 6.5% · amino-acid nitrogen from molasses extract 5.5% · kieserite 5.5% · sulphate of potash 5.2% · malted barley 4.5% · biochar 4.5% · humic acid 1% · fulvic acid 1% · boron complexed with humic acid 0.15%

What the feed delivers — and what your plants need

Every level is set against peer-reviewed trials on flowering and fruiting crops, not tradition. Here is what a standard build puts into the soil solution, against what the plant actually wants — and the one that matters most is phosphorus.

What the feed delivers, against what the plant needs A standard build, in the soil solution Potassium 60 175 ~160 mg/L delivered Phosphorus 25 30 ~27 mg/L delivered Magnesium 35 70 ~55 mg/L delivered what the plant needs what this feed delivers
Nutrient This feed delivers Flowering plants need Fruiting & root veg need
Nitrogen high in veg, lean through flower low in flower — lifts flavour moderate and steady
Phosphorus ~27 mg/L, from the charge 25–30 mg/L 35–50 mg/L — add extra P
Potassium ~160 mg/L 60–175 mg/L ~300 mg/L — add extra K
Calcium high, from day one to sufficiency high
Magnesium ~55 mg/L 35–70 mg/L 35–70 mg/L

"But don't flowers need a phosphorus spike?"

It is the most common belief in growing, and the peer-reviewed answer is no. A flowering plant's phosphorus demand is real but modest, and the same 25–30 mg/L in the soil solution covers every stage — bloom included. Raise it above that and flower number and weight do not move (Westmoreland & Bugbee 2022; Shiponi & Bernstein 2021). A "PK spike for bloom" sells feed; it does not grow more flower. Bloom boosters seem to work only because they also cut the nitrogen — and it is the lower nitrogen doing the work, not the phosphorus. Dr Forest gets that effect honestly: nitrogen steps down in the Bloom blend while the charge holds phosphorus flat at the level the flower actually uses.

How much phosphorus you feed — Dr Forest vs the rest

Every other living-soil feed bundles phosphorus into the amendment and re-adds it each grow. This is the phosphorus in the feed itself, from each product's own published analysis.

Living-soil feed P₂O₅ in the feed How it is applied
Dr Forest Veg & Bloom 0.4% a separate one-time charge
Leading grow-stage feeds 3% in the feed, re-added every grow
Craft bloom blends 5% in the feed
High-phosphorus bloom feeds 8% in the feed, every grow

Some of these use the same micronised rock phosphate Dr Forest does — they simply bundle it into a 3–8% feed and re-apply it every stage, every crop. Dr Forest works it in once as a separate charge and takes only a third on reused soil, so the soil never loads up.

Why re-amending a 3–8% phosphorus feed goes wrong

Rock phosphate and bone meal are slow-release — they weather over years, not weeks. A feed carrying 3–8% phosphorus doses that slow mineral at a rate that would only make sense for a fast inorganic salt the plant uses up each cycle. But slow phosphorus does not leave. Re-amend every grow and you add it far faster than the plant can take it up, so it climbs.

01It builds past what a plant can use

A plant draws about 25–30 mg/L of phosphorus from the soil solution and no more. Above that there is no gain in growth, flower or fruit (Westmoreland & Bugbee 2022) — everything past sufficiency simply accumulates.

02It competes with zinc and iron

Surplus phosphorus competes with zinc and iron for uptake — an effect set by the phosphorus-to-zinc balance rather than a single figure, and worst on soils already low in zinc. They are the two micronutrients behind a clean finish and behind aroma and flavour; the blends carry seaweed and a full micronutrient package to keep them available. The plant can look fed and still run short of them.

03It peaks at the wrong moment

Slow phosphorus added early and topped up each cycle sits at its highest late in the grow and into the next — exactly when you want the feed easing off for a clean ripening. You cannot turn a banked mineral back down.

04The science shows no upside

In controlled trials, raising phosphorus above sufficiency does not lift yield or quality. It raises tissue phosphorus, micronutrient antagonism and leaching instead (Westmoreland & Bugbee 2022; Shiponi & Bernstein 2021).

Why phosphorus does not belong in the feed

Put a slow phosphorus into the feed and top-dress it cycle after cycle, and it stacks in the soil far faster than the plant can draw it down.

What phosphorus does to a re-used soil Soil solution phosphorus, mg/L, over four grows in the same soil surplus — zinc & iron increasingly tied up 25–30 — all a plant needs Grow 1 Grow 2 Grow 3 Grow 4 30 52 78 104 Feed with P bundled in (most brands) Dr Forest — P as a separate charge, cut to ⅓ on re-use Phosphorus is slow: only ~a third releases per grow, the rest banks. Put it in the feed and re-amend, and it climbs every cycle — competing with iron and zinc, and leaving a loaded soil that never finishes clean.

Either way, you pay for it

In a living soil the phosphorus stays put. Bundled into an all-in-one feed, you cannot turn it down without starving the nitrogen and potash the plant still needs — so on a reused soil it only ever climbs, when all you actually needed to replace was nitrogen and potassium. The soil gets harder to run each year, not easier.

In a soluble mineral feed the phosphorus you do not need just washes out — expensive run-off, and a pollution problem, for no benefit to the plant.

Dr Forest keeps phosphorus in a one-time charge instead: top up nitrogen and potassium by the week, and the banked phosphorus holds steady at what the plant actually uses.

Dr Forest keeps it separate — so the soil lasts

Phosphorus lives in a one-time charge, worked in once and never fed again. On a second or third grow you take just a third of the charge — because last year's is still banked — while nitrogen, potash, calcium and magnesium carry on at full strength. Phosphorus stays flat at the ~27 mg/L the plant actually needs, the soil never loads up, and it finishes clean grow after grow. Our bloom feed carries 0.4% phosphate; a typical "bloom" amendment carries 5–8%.

Why the charge goes in a week before planting

Phosphorus is slow, so you add it before the plant needs it — not when it needs it. Worked into the soil at planting, it has the whole veg phase to weather, and it is ready and waiting the moment bloom demand climbs. Add the same slow phosphorus at the flip instead and it is barely started — still locked in the mineral through the weeks the plant wants it most, and only catching up long after flowering has peaked.

Slow phosphorus, added early, is ready for bloom Phosphorus available to the plant (%), across a grow BLOOM — WHEN P IS WANTED MOST 0% 50% 100% wk 0 wk 2 wk 4 wk 6 wk 8 wk 10 wk 12 worked in Worked in at planting — ready for bloom Added at the flip — too late Phosphorus is slow, so you add it before it is needed — not when it is needed. Worked into the soil at planting, it has the whole veg phase to build, and it sits near maximum exactly when bloom demand peaks. Add the same slow phosphorus at the flip and it is still weathering long after the plant wanted it.

The phosphorus charge

ABone meal — 3.5-18.5

Finely ground and steamed. A biological apatite, so soil acid and biology break it down readily. The more reliable of the two: faster, less fussy about pH, more forgiving if your soil drifts. It carries a little nitrogen of its own, which nudges a build gently towards yield.

BMicronised rock phosphate — 31% P₂O₅, 46% CaO

The plant-based choice, and nitrogen-free — so it holds the flower at its leanest, the flavour build. Ground fine so soil biology and root acids can weather it. Slower than bone meal and far more dependent on an acidic soil, so keep the pH near 6.2 and take mycorrhizal fungi with it.

Rates

Phosphorus charge — bone meal

9g per litre of soil. Mixed through the soil a week before planting. Once per cycle.

Phosphorus charge — rock phosphate

12g per litre of soil. Higher than bone meal, because it releases more slowly and depends more on soil acid.

Reused soil

A third of the charge. Blends stay at full strength.

Veg

5.6g per litre across the growing phase (4.7g lean for flavour, 6.5g for maximum yield). Top-dressed weekly.

Bloom

8g per litre across flowering (6.7g lean for flavour, 8.5g for maximum yield, with a mid-flower nitrogen booster). Top-dressed weekly.

The finish

Plain water for the last two to three weeks.

How much for your soil

Soil Bone meal or Rock phos Veg Bloom
80 litres 720g 960g 448g 640g
120 litres 1,080g 1,440g 672g 960g
200 litres 1,800g 2,400g 1,120g 1,600g

Standard (Balanced) build. On reused soil, take a third of the phosphorus charge and leave the blends as they are.

Get your pH right or none of it works

Aim for 6.2 to 6.5. Slightly acidic soil is what dissolves the phosphorus charge — above about 6.8 the release slows sharply, and no amount of extra phosphorus will fix a pH problem.

If you have chosen rock phosphate, aim for 6.2. It leans on soil acid far more than bone meal does, and it carries calcium and a little carbonate that gently nudge pH upward — the direction that slows its own release. Check your pH mid-cycle rather than assuming it has held.

Veg and Bloom at full strength, and only a third of the phosphorus charge. Last year's phosphorus is still banked in the soil, so you top it up rather than starting again. Add compost to replace the organic matter and you are away.
Usually phosphorus. A complete feed puts phosphorus in every scoop, and because it is slow-release it banks in the soil faster than plants use it. By the third year the soil is loaded with it, which competes with zinc and iron for uptake and quietly caps results. And you cannot fix it — turning the phosphorus down would starve the nitrogen. Keeping phosphorus as a separate charge is what lets you cut it back while everything else stays at full strength.
A little more Veg and Bloom, plus a nitrogen booster in mid-flower — the nitrogen is what adds weight. Not more phosphorus, and not a big jump in the blends: potash and magnesium have ceilings you do not want to cross. The charge is sized by soil volume, so it does not change.
Bone meal is the more reliable: it releases faster, it is less fussy about pH, it forgives a drifting soil, and it adds a little nitrogen. Micronised rock phosphate is the plant-based, nitrogen-free option — it keeps the flower leanest for flavour, but it wants an acidic soil (6.2), mycorrhizal fungi, and a higher rate: 12g per litre against 9g.
It releases more slowly. Bone meal is a biological apatite — less crystalline, more readily broken down. Rock phosphate is a mineral apatite and needs more acid, more time and more help from soil fungi. Nothing is wasted: whatever does not release this cycle banks for the next.
Because phosphorus does not belong in a feed. It is slow, it banks for years, and it only needs applying once. In every scoop it gets over-applied — and excess phosphorus gives no extra yield or quality, it just competes with zinc and iron and runs off.
No. Studies consistently find high phosphorus does not increase flower numbers, and commercial flower growers run low phosphorus relative to nitrogen. Bloom boosters appear to work because they carry reduced nitrogen — it is the drop in nitrogen doing the work, not the phosphorus.
A week before planting. It needs moisture, time and soil acid to begin dissolving. Neither charge burns, so you can plant into it — but a week's head start means the phosphorus is ready when the roots are.
No. Every ingredient depends on soil biology to release it. In an inert medium there is nothing to do the work. These are soil products.
With rock phosphate, near-essential — the fungi are the main biological route to weathering slow mineral phosphorus. With bone meal, still a real gain. See our mycorrhizal fungi powder, and what mycorrhizal fungi do for the background.
Made with organic ingredients and handcrafted in small batches. We do not hold a certification, so we do not claim one. The Veg and Bloom blends are plant-based; bone meal is animal-derived, so if you want a fully plant-based soil, choose rock phosphate.

Dr Forest — Made by Growers. Backed by Science.

Handcrafted in Stockport, Greater Manchester. Named after Joe's grandfather Dr Forrest, a GP near Preston who kept a back-garden plot for the runner beans he turned into piccalilli.

Grower guides

Everything you need to run the programme, step by step:

Feeding calculator · Feeding schedule · Phosphorus & flavour: the science
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