Author: Tony Callaghan

TL;DR Multipurpose Compost (MPC) is a modern, soilless, all-purpose mix designed for ease of use. John Innes 1, 2 and 3 are traditional, soil-based formulas graded by nutrient strength and tailored to plant growth stages. Composition Multipurpose Compost  (MPC): Peat-free or reduced-peat blends using wood fibre, coir, bark or green compost. Lightweight, easy to handle, and…

Summary John Innes composts are classic soil-based growing media developed in the 1930s by horticultural scientists at the John Innes Horticultural Institution. They remain excellent for structured, long-term container growth — but differ completely from today’s soilless Multipurpose Composts (MPCs). The formulas are public domain and can be made at home using garden soil, sand and…

Short answer: No — not all plants or seeds thrive in standard Multipurpose Compost. Most retail MPCs are nutrient-rich, fine-textured and microbially inactive, designed for convenience in pots and containers. But seedlings, acid-loving plants (like azaleas and blueberries), and some delicate ornamentals need different textures, lower nutrient levels, or a pH-adjusted base to avoid stress…

Most gardeners can safely re-use last year’s Multipurpose Compost (MPC) — provided it’s refreshed before planting again. Simple refresh Soil-building re-energise Check the pH: most MPC starts slightly acidic (pH 5.5–6.5) and is balanced with lime during manufacture. After a season, lime and base nutrients wash out and natural acids form — so pH often…

Even within the same garden centre, two bags labelled “compost” can behave very differently. Here are the six most common reasons. The wrong product for the job A key distinction is between PAS100 compost and Multipurpose Compost  (MPC). Confusing these two markets — or mixing bulk PAS100 feedstock into retail blends — often leads to…

For first-time growers, planting up is the exciting bit — but the real success comes from day-to-day care. Multipurpose Compost (MPC) gives plants a great start, but it needs a little attention to keep performing. Understand How MPC Behaves Watering – Get the Balance Right Feeding – Replace What’s Used Refreshing – Keep Structure and Life…

Short answer: Not all multipurpose composts are the same? — but they’re all designed with the same goals in mind. All major compost makers aim for roughly the same performance — good aeration, moisture balance, and short-term feeding — but they reach those targets using different ingredients and production methods. Some rely more on coir,…

Yes — indoors, clean compost wins every time. Full FAQ Yes — Multipurpose Compost (MPC) is one of the safest and simplest ways to grow healthy indoor plants. It’s clean, consistent, and far less likely to bring uninvited guests into your home. Indoors, there’s no rain, no predators, and no UV to keep soil bugs in…

Yes — with a little care. If you’ve got an unopened bag from last year, check it and carry on. If it’s compost that’s already done a season in pots or beds, don’t bin it — you can almost always bring it back to life. Last year’s unopened (or partly used) bag If you kept…

The short answer. Yes — most MPCs only feed for a few weeks. After that, plants depend on you for nutrients. Why this happens. Multipurpose compost is designed to be light, clean, and convenient. It’s usually made from peat-free blends of coir, green compost, and fine wood fibre. These ingredients have low inherent nutrition and…