Fertilising: when and with what?

Feeding: less is often more

Every plant needs nutrients, just like us. But too much fertiliser causes more problems than too little. Overfed plants grow soft and are more prone to disease. The art is giving the right amount at the right time.

GardenWorld helps you visualise a garden design suited to your soil type. Know your plants and you can fine-tune your feeding programme perfectly.

The seasonal schedule

Early spring (March-April)

This is the main event. Most plants begin their growing season and need food now. Spread a layer of mature compost or an organic general-purpose fertiliser around perennials and shrubs. Garden centres and RHS partner shops carry good organic options.

Feed your lawn with a specific lawn fertiliser once the grass starts growing again. Not too early, or you'll mainly be feeding the weeds.

Late spring (May-June)

Container plants and newly planted annuals get a boost now. Liquid organic feed works quickly and is ideal for pots and containers. Roses appreciate a second feed around flowering time.

Summer (July-August)

Go easy. Most perennials and trees have enough from their spring feed. Only heavy bloomers like hydrangeas and container plants need an extra dose. Stop feeding shrubs after mid-July, as new growth now will be too tender for winter.

Autumn (September-October)

Feed the lawn with a special autumn fertiliser rich in potassium. That strengthens roots for winter. Ornamental borders get a layer of compost as winter cover and preparation for next year.

Organic versus synthetic

Organic fertilisers (compost, manure, blood meal, bone meal) work slowly. They feed not just the plant but also soil life. Nutrients release gradually. That's better for the soil long term.

Synthetic fertilisers (granules, liquid plant food) work fast. Handy when a plant is clearly deficient, but they add nothing to soil structure. Feel free to combine both: compost as a base, synthetic as a correction.

NPK: the three letters

Every fertiliser packet shows three numbers. They represent nitrogen (N), phosphorus (P) and potassium (K).

Nitrogen: leaf growth. Lawns and leafy vegetables need plenty.

Phosphorus: root growth and flowering. Flowering plants and newly planted shrubs benefit.

Potassium: resilience and fruit formation. Key for fruit trees and winter hardiness.

Choose a fertiliser that matches what your plant actually needs, not simply the highest numbers.

Common mistakes

Over-feeding: leads to root burn and environmental pollution through leaching. Stick to the dose on the packet.

Wrong timing: fertilising in full summer or late autumn causes problems. Plants can't absorb it or put on vulnerable late growth.

Dry spreading: never scatter granular fertiliser on dry soil. Water first or feed just before rain. Otherwise the granules scorch roots.

A soil test as starting point

Not sure what your soil needs? Do a soil test first. It shows any deficiencies and prevents you adding what's already abundant. Too much phosphorus is environmentally damaging and hard to fix.

Special cases

Rhododendrons and hydrangeas: need ericaceous feed. Standard general-purpose is too alkaline.

Veg patch: heavy feeders (tomatoes, courgettes) get a top-up every three weeks. Light feeders (carrots, herbs) manage on the spring feed.

New plantings: skip fertiliser in the first year. The plant needs to root first, not explode above ground.

Feed smart, not more

Good fertilising is about timing, dosage and choosing the right product. Less is often better than more. Design your garden at GardenWorld so you know exactly what each plant needs.