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 limited capacity to hold fertiliser for long.

To give a short boost, manufacturers add a starter charge of fertiliser — typically enough for 4 to 6 weeks of growth.

After that, it’s like running a car on fumes: plants start to slow, leaves pale, and flowering tails off.

What to do.

• Feed regularly once growth starts. A balanced liquid feed (tomato feed, seaweed extract, or general all-purpose fertiliser) every 1–2 weeks keeps things ticking.
• Top up long-term pots. For bigger containers, mix in a controlled-release fertiliser pellet or a small amount of composted manure or a biochar-humus composite when planting.
• Water wisely. Nutrients move with water — overwatering flushes them out faster.

A gardener’s tip.

If you notice a brand claiming “feeds plants up to six months,” check the fine print. That’s under ideal watering conditions — and usually only if you’re using the full recommended amount of slow-release granules. Real-world results vary widely.

Soil-builder’s view.

If you prefer a “feed-the-soil” approach rather than “feed-the-plant,” start blending MPC with home compost or biochar-based mixes. These build natural nutrient cycling — so the feeding gap narrows with every season.

Summary.

Think of multipurpose compost as a starter mix, not a full meal. It gets plants growing fast — but you’re still the chef who keeps them fed.