Phostrogen alternative
Organic too, and cheaper by the kilo
Phostrogen Organic All Purpose Plant Food is a 6-3-6 organic granular feed, enriched with seaweed and sold in an 800 g box. All Purpose 4-4-4 is a granular feed blended from ten named organic ingredients, with calcium, magnesium, sulphur, seaweed, humic acid and biochar. Phostrogen names one ingredient: seaweed. We name all ten. Ours also costs less by the kilo: £5.11 to £8.00, against £8.11 to £10.61 for Phostrogen Organic.
£12.00 All Purpose 4-4-4, 1.5 kg
Choose All PurposeBigger plot? 4 kg is £24.50. 9 kg is £46.00 with free UK delivery.
★★★★★ Rated 4.95/5 from 513 reviews. Free UK delivery over £40. Dispatched in 1 to 2 working days. Formulated and blended in Stockport, in compostable bags.
- All Purpose 4-4-4 does the same job as Phostrogen Organic: one organic granular feed for beds, borders, pots and planters.
- Phostrogen's product description names one ingredient, seaweed. Ours names all ten, with what each one does.
- Per kilo: £5.11 to £8.00 with ours, £8.11 to £10.61 with Phostrogen Organic.
- Per square metre: Phostrogen Organic is cheaper, at 41p to 53p against our 51p to 80p, because its box rate is 50 g per m² and ours is 100 g.
- Ours carries calcium, magnesium and sulphur, plus seaweed, humic acid and biochar.
- Ours comes in 1.5 kg to 9 kg bags and larger. Phostrogen Organic comes in one 800 g box.
- Not vegan: All Purpose 4-4-4 contains bone meal. Phostrogen Organic is sold as suitable for vegans.
What it costs
Pack price divided by pack weight.
Phostrogen Organic at 50 g per m², from its box coverage of up to 16 m²; ours at 100 g per m².
Why the two charts differ. Phostrogen Organic goes on at half the weight, so each square metre costs less. Ours puts down twice the material for 10p to 27p more: 100 g of organic matter and minerals per square metre against 50 g.
Phostrogen Organic: the 800 g box states it covers up to 16 m² and feeds for up to 100 days; 800 g boxes at £6.49 to £8.49 from five UK retailers, checked 14 Nov 2026. Dr Forest from £12.00 (1.5 kg), £24.50 (4 kg) and £46.00 (9 kg) bags. Phostrogen is a trademark of its owner; Dr Forest is not affiliated.
What is in the bag
Organic tells you how a feed was produced. It does not tell you what you are putting on your soil. Phostrogen's product description names one ingredient, seaweed, and leaves the rest unnamed. Every input in All Purpose 4-4-4 is named, with the job it does.
| Phostrogen Organic All Purpose | Dr Forest All Purpose 4-4-4 | |
|---|---|---|
| Ingredients named | 1 | 10 of 10 |
| Nitrogen from | Not named | Alfalfa meal, flaxseed meal, nitrogen plant extract |
| Phosphorus from | Not named | Bone meal |
| Potash from | Not named | Sulphate of potash |
| Calcium, magnesium, sulphur from | Not named | Gypsum, kieserite |
| For soil life | Seaweed | Scottish seaweed, humic and fulvic acid, fermented biochar |
Phostrogen Organic column from the manufacturer's product description and UK retailer listings, checked 14 Nov 2026.
What sets ours apart
Both are organic granular feeds that soil life breaks down over weeks. This is where they differ.
- Every ingredient named. Ten organic inputs, each one on the label. Phostrogen's product description names seaweed and nothing else.
- Cheaper by the kilo. £5.11 to £8.00 against £8.11 to £10.61. Every bag size of ours comes in under the Phostrogen Organic box.
- Calcium, magnesium and sulphur built in. Gypsum, kieserite and bone meal supply them.
- Humic acid and biochar as well as seaweed. They feed soil life and help the soil hold on to nutrients and water.
- Bags sized for a plot. A 9 kg bag covers 90 m². One 800 g box of Phostrogen Organic covers up to 16 m².
- Small batches, compostable bag. Formulated and blended in Stockport.
Side by side
| Phostrogen Organic All Purpose | Dr Forest All Purpose 4-4-4 | |
|---|---|---|
| Type | Organic granules, enriched with seaweed. Other ingredients not named | Granular, blended from ten named organic ingredients |
| NPK | 6-3-6 | 4-4-4 |
| Also carries | Seaweed | Calcium, magnesium, sulphur, seaweed, humic acid, biochar |
| How you feed | Sprinkle on the soil, work in and water. An 800 g box covers up to 16 m² and feeds for up to 100 days | 100 g per m², every 6 weeks, up to 3 times a season |
| Animal ingredients | None. Sold as suitable for vegans | Bone meal |
| Cost per kilo | £8.11 to £10.61 | £5.11 to £8.00 |
| Packs | 800 g, £6.49 to £8.49 | 1.5 kg £12.00, 4 kg £24.50, 9 kg £46.00 |
Phostrogen Organic analysis, coverage and directions from the UK box and retailer listings, checked 14 Nov 2026.
How to switch
Use All Purpose 4-4-4 wherever you would reach for Phostrogen Organic. Start in spring as growth begins:
| Where | Rate | How often |
|---|---|---|
| Beds, borders, allotments | 100 g per m², worked into the top 5 to 10 cm | Every 6 weeks while growing, up to 3 times a season |
| Potting up | 5 g per litre of compost. Heavy feeders: up to 10 g | Once, at potting |
| Pots and baskets in growth | 2 g per litre of pot, scattered on top | Every 4 weeks, from 6 weeks after potting |
A handful is 40 to 50 g; a level tablespoon is 12 to 15 g. Water in every time.
Need help with a particular plant? Our How to Grow Plants guides cover 194 plants, from sowing to harvest.
When Phostrogen Organic makes sense
- You want a vegan feed. Phostrogen Organic is sold as suitable for vegans; ours contains bone meal.
- You want the lowest cost per square metre. At its box rate, Phostrogen Organic wins that.
- You want the Organic Farmers & Growers logo on the pack. Phostrogen Organic carries it.
- You have a few pots or one small bed, and an 800 g box is all you need.
Common questions
What is the closest Dr Forest match to Phostrogen Organic All Purpose?
Dr Forest All Purpose 4-4-4. Both are organic granular feeds for the whole garden: veg, fruit, flowers, shrubs and pots, and both are broken down by soil life and released over weeks. The NPK numbers differ because the blends differ. Phostrogen Organic is 6-3-6. All Purpose 4-4-4 is balanced, and more of the bag is given over to calcium, magnesium and sulphur, seaweed, humic acid and biochar, with the nutrients held in that organic material.
What is in Phostrogen Organic?
Phostrogen's product description says it is enriched with seaweed and suitable for vegans. It does not name the other ingredients. Dr Forest All Purpose 4-4-4 names all ten: alfalfa meal, bone meal, nitrogen plant extract, flaxseed meal, gypsum, sulphate of potash, kieserite, Scottish seaweed, humic and fulvic acid, and fermented biochar.
Is Dr Forest cheaper than Phostrogen Organic?
By the kilo, yes: £5.11 to £8.00 for Dr Forest All Purpose 4-4-4 against £8.11 to £10.61 for Phostrogen Organic All Purpose (prices checked 14 Nov 2026). Per square metre, no: Phostrogen Organic costs 41p to 53p at its box rate of 50 g per m², against 51p to 80p for Dr Forest at 100 g per m².
Is Phostrogen organic?
There are two ranges. The original Phostrogen All Purpose Plant Food is a 16-10-24 soluble mineral feed and is not organic. Phostrogen Organic All Purpose Plant Food is a separate 6-3-6 granular product, certified for organic gardening by Organic Farmers & Growers. Dr Forest All Purpose 4-4-4 is blended from ten organic ingredients, and the alfalfa meal and flaxseed meal are certified organic.
How often should I use Phostrogen Organic?
The box says it feeds for up to 100 days, and one 800 g box covers up to 16 m². Dr Forest All Purpose 4-4-4 goes on at 100 g per m² every 6 weeks while plants are growing, up to 3 times a season.
Is Phostrogen Organic suitable for vegans?
It is sold as suitable for vegans. Dr Forest All Purpose 4-4-4 is not: it contains bone meal.
Can I use Phostrogen Organic and Dr Forest All Purpose together?
Yes, but not both at full rate on the same bed. Finish the box first, then move to All Purpose 4-4-4 at the next application.
More: all brand alternatives · Miracle-Gro All Purpose · Vitax Q4 · Osmocote
Ready to know what is in the bag?
Ten named organic ingredients, one balanced feed, from £5.11 a kilo.
£12.00 All Purpose 4-4-4, 1.5 kg