RocketGro Range Explained and Compared
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RocketGro make all three from British farm crops, and all three are certified organic by the Soil Association and completely peat-free. One is a growing medium for pots, one goes into the soil, and one goes on top as a mulch.
Multi Purpose is my pick if you are not sure which to buy. It handles seeds, pots and raised beds, with the feed already in the mix.
pH 5.5 to 6.5 · NPK 12-12-17 · Feeds for 3 to 4 months
Ericaceous is the peat-free, option for acid-lovers like blueberries and rhododendrons, especially on chalky ground.
pH 4 to 5 · Peat free · For acid-loving plants
John Innes No.3 is the one to put a tree or a big shrub into. The loam gives it weight, so it holds its structure for years, not months.
55% loam · pH 6.0 to 6.5 · Great drainage
All three are certified organic by the Soil Association, 100% peat-free, vegan friendly, pet safe, seed free, made in Somerset from British-grown crops, and sold in 50 litre bags.
| RocketGro Multi Purpose Compost | RocketGro Soil Improver | RocketGro Magic Mulch | |
|---|---|---|---|
| What it is | A growing medium for pots and trays | A soil conditioner, forked in or laid on | A surface mulch |
| Made from | Bark fines, wood chip fines, bracken and PAS 100 compost | British maize, rye and grass blended with PAS 100 compost | British maize, rye and grass |
| Feed | A 10-week feed up front, then slower release to three months | NPK 4-2-6, feeding gently for up to three months | NPK 4-2-6 |
| How to use it | Fill pots, trays, baskets and raised beds | Fork it in, or lay 5cm as a no-dig mulch | Spread 5 to 7.5cm on the surface |
| Best for | Potting, seed sowing, hanging baskets, containers | Breaking up heavy clay, tired vegetable beds, no-dig | Weed suppression and holding moisture in beds and borders |
| Not for | Permanent containers, where a loam-based compost holds up better | Seed sowing on its own | Filling pots, it is a surface material |
| Price | Price range: £187.00 through £284.00 inc. VAT | Price range: £242.00 through £384.00 inc. VAT | Price range: £162.00 through £384.00 inc. VAT |
| Choose bag size | Choose bag size | Choose bag size |
Why Professionals & Homeowners Choose RocketGro
Most peat-free composts are a compromise you put up with. This range is not, and the reason is what it is made from. RocketGro grow maize, rye and grass in Somerset and digest the crop, so what you are buying is a living material full of microbes rather than milled bark with fertiliser stirred through it. It costs more than green waste compost and it does a different job.
- All three carry Soil Association organic certification.
- None of the three contains any peat.
- RocketGro digest the crop rather than milling bark, so the material is full of microbes, which is what helps a tired bed.
- RocketGro is vegan, with no animal waste and no added chemicals, and pet safe on the manufacturer’s own labelling.
- All grown and made from named British crops.
Product Comparison of the RocketGro Range
RocketGro Multi Purpose Compost
RocketGro Multi Purpose Compost is the peat-free all-rounder, and the one to reach for where an ordinary multi purpose would do. It is a blend of bark fines, wood chip fines, bracken and refined PAS 100 compost, with a 10-week feed up front and a slower release after that running to about three months.
- Suits potting, container planting, hanging baskets, seed sowing, cuttings, raised beds and general planting.
- Two-stage feed, so it does not run out at six weeks the way some peat-free mixes do.
- Good water retention.
- For a permanent container that will not be repotted for years, a loam-based compost holds its structure better. Use John Innes No.3 for that job.
RocketGro Soil Improver
RocketGro Soil Improver is the one I would put on heavy clay. It is British-grown maize, rye and grass blended with PAS 100 compost, naturally sterilised at 55°C for 40 days or more, and it carries NPK 4-2-6 along with a live microbial population.
- Breaks up heavy clay and improves structure, and the microbes keep working after the material itself has gone.
- Works in a border, a raised bed, a container or along a lawn edge, which is unusual for a soil improver.
- Lay 5cm on the surface for no-dig, or fork it in when you are making new ground.
RocketGro Magic Mulch
RocketGro Magic Mulch is a mulch that feeds rather than just covers. Same British maize, rye and grass, same NPK 4-2-6, same 55°C sterilisation, but graded and sold to go on the surface rather than into the ground.
- Suppresses weeds and holds moisture while feeding the bed underneath as it breaks down.
- Seed free out of the bag, so you are not laying next year’s weeding on top of this year’s.
- Encourages worms and insects, which is the point of mulching with something organic rather than with stone.
- The only one of the three available in a 700L builders bag.
Applications
The simplest way to pick is to ask where the material ends up. In a pot, it is the Multi Purpose. Into the ground, it is the Soil Improver. On top of the ground, it is the Magic Mulch. All three cost more than the conventional equivalent, and what you are paying for is the organic certification, the British sourcing and the living microbes rather than a bigger bag.
- For no-dig beds, lay Magic Mulch 5 to 7.5cm on the surface and plant straight through.
- On heavy clay borders, fork the Soil Improver in the first year, then mulch each autumn after that.
- For containers and hanging baskets, use the Multi Purpose Compost with a liquid feed from about three months.
- For raised beds, fill with the Multi Purpose and top up with the Soil Improver in later years.
- Around fruit and roses, Magic Mulch works well, kept clear of the stems.
Inspirational Ideas & DIY Guides
How I quickly determine the type of soil I’m working with.
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The 3 components of soil, how to test them, and what I look for when choosing the best top soil.
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Maintenance
The feed in all three runs for about three months, so anything potted or mulched in spring wants topping up or liquid feeding by late summer.
Purchasing Tips
All three come in 50 litre bags, so work out what you need before you order: for a surface mulch at 7.5cm that is 75 litres per square metre, and for filling a container it is simply the volume of the pot. Magic Mulch is also sold in a 700L builders bag, which is the one to take if you are doing a whole border rather than a few pots.
FAQs
What is the difference between RocketGro Soil Improver and Magic Mulch?
RocketGro Soil Improver is made to go into the ground and Magic Mulch is made to go on top of it, and the Soil Improver has PAS 100 compost blended into it as well. Both carry NPK 4-2-6, so pick by where the material ends up rather than by what is in it.
Is RocketGro peat-free?
All three RocketGro products are 100% peat-free and certified organic by the Soil Association. They are made in Somerset from British-grown maize, rye and grass rather than from peat or imported coir.
Is RocketGro safe to use around pets?
RocketGro is labelled pet safe and is vegan, with no animal waste of any kind in it. That is the practical difference from a manure-based improver, which dogs will often dig at and roll in.
Can I sow seeds in RocketGro Multi Purpose Compost?
RocketGro Multi Purpose Compost is sold for seed sowing and cuttings as well as for potting, and the 10-week feed in it suits young plants. Sieve it for very fine seed, as you would with any multi purpose mix.
What does NPK 4-2-6 mean?
NPK 4-2-6 gives the percentage of nitrogen, phosphorus and potassium in the material, in that order. The high potassium relative to nitrogen suits flowering and fruiting plants, and it is a gentler balance than a bagged fertiliser, which is why it feeds over three months instead of all at once.
Why is RocketGro more expensive than ordinary compost?
RocketGro costs more because it is Soil Association certified organic, grown and processed in Somerset from named British crops, and sold as a living material rather than as bulk organic matter. Where you only need volume to improve a large area, Green Compost does that job at well under half the price.
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RocketGro Multi Purpose Compost
Price range: £187.00 through £284.00 inc. VAT -
John Innes No.3 Compost
Price range: £127.00 through £232.00 inc. VAT -
Woodchip Mulch
Price range: £112.00 through £277.00 inc. VAT -
Multi Purpose Compost
Price range: £122.00 through £297.00 inc. VAT
