TL;DR:
Use a specialist compost when your plants genuinely need a very specific pH, nutrient, or drainage balance — for example, seeds, ericaceous plants, orchids, or citrus. For most other “for tomatoes/roses/vegetables” mixes, a good-quality Multipurpose Compost (MPC) plus the right feed at the right time will do the job just as well.
Why it matters
“Multipurpose” means suitable for most — but not all — plants. Some have narrow needs that MPC can’t meet. At the same time, the market has become crowded with products labelled “for roses,” “for bulbs,” “for vegetables,” and so on. Understanding which are truly different (and worth the price) helps you buy smarter.
1. True specialist composts — worth paying extra for
| Type | When to use | Why not MPC? |
|---|---|---|
| Seed compost | For sowing and germination | MPC is too coarse and nutrient-rich. Fine, low-nutrient seed compost prevents seedling scorch. |
| Ericaceous compost | For acid-loving plants such as azalea, rhododendron, camellia, and blueberry | MPC is near-neutral (pH 6–7). Ericaceous compost stays acidic (pH 4–5). |
| Citrus compost | For lemons, limes, and other indoor citrus | Needs sharp drainage and mild acidity. Can be DIY by mixing fine grit into MPC. |
| Orchid compost | For orchids or bromeliads | Requires very open structure (bark, coarse fibre). MPC would smother roots. |
| Cactus/succulent compost | For drought-tolerant plants | MPC holds too much water; cactus compost adds grit or sand for fast drainage. |
Cost note: these mixes are smaller-volume, lower-throughput products — so they’re usually a few pounds more per bag. It’s fair value for what’s inside.
2. Branded “for tomatoes/roses/vegetables” composts — what’s really different?
| Label says | What it usually means | Reality check |
|---|---|---|
| “For tomatoes” | MPC with added potassium fertiliser or slow-release feed | You can achieve the same by adding a tomato feed after week 6. |
| “For roses” | MPC or loam-based compost with added rose feed | Add your own rose or potash feed instead; saves money and plastic. |
| “For vegetables in containers” | MPC with extra wood fibre for drainage | Regular MPC plus balanced liquid feed works fine. |
| “For bulbs” | MPC with sand/grit for drainage | DIY: mix in 20–30% sharp sand yourself. |
| “For herbs” | Often just standard MPC relabelled | Most herbs prefer free-draining soil — add a little grit if needed. |
Bottom line: these mixes make gardening more convenient but not more effective. They mainly exist to simplify the shelf choice (and add margin for the retailer).
3. DIY shortcuts and blending tips
- For citrus or bulbs: add 10–20% fine grit or sharp sand.
- For seedlings: sieve MPC and mix 1:1 with leaf mould or coir.
- For veg or roses: start with MPC and add a balanced feed at week 4–6.
- For acid-lovers: add pine needles or sulphur dust to lower pH slightly.
See How to mix MPC with topsoil for blending ratios.
4. How to spot genuine specialist products
- Real specialist composts state pH, nutrient levels, or ingredients clearly.
- Vague claims like “for healthy plants” or “environmentally friendly” mean little.
See How to read compost bag labels.
Summary
True specialist composts (seed, ericaceous, cactus, orchid, citrus) are genuinely different and worth using. Branded “for tomatoes / roses / vegetables” mixes are mostly marketing variants of standard MPC. Save money and plastic: buy one good MPC, and tweak it with feeds or grit to suit each plant’s needs.
Disclaimer.
Brand names such as Westland, SylvaGrow, RocketGro, Dalefoot, Carbon Gold, and others mentioned on this site are registered trademarks of their respective owners. MultipurposeCompost.co.uk includes these examples for informational and comparative purposes only and does not claim endorsement, affiliation, or suitability for any specific use. Gardeners and buyers should always check current product specifications and manufacturer guidance before purchase or application.
