Wondering which compost or soil is best for your plants? Our simple guide demystifies the science and explains what's what

Choosing the right compost or soil conditioner for your plants will help them to grow to their full potential. Some potting composts are enriched with nutrients, too, helping your purchases to establish quickly in their new homes. As well as the composts and conditioners listed, you can also buy products formulated for specific plants, such as vegetables, cacti and citrus trees.

Seed and cutting compost

seed and cutting compost
The perfect choice for growing seeds or taking cuttings, a product such as Gro-Sure Seed & Cutting Compost has a fine texture so it can establish contact with even the tiniest of seeds. It is free-draining to help prevent fungal diseases, and contains the right amount of plant nutrients to support seedlings.


An all-purpose compost, such as Westland Jack’s Magic, is the ideal choice for annual plants and flowers, and for hanging baskets and windowboxes. Most multi-purpose composts are made from lightweight organic materials and are enriched with nutrients that will sustain potted plants for the first few weeks.

John Innes

john innes
Composts labelled John Innes contain sterilized loam, and are similar in texture to garden soil. They are perfect for plants that will be in their pots for more than one year. You may also see the number 1, 2 or 3 on packs, which relates to their nutrient formula – number 3 contains the highest proportion of nutrients and is the best choice for shrubs, trees and perennials.


John Innes Ericaceous Compost contains some loam, and is designed specifically for plants that like acid soil. Use it to pot up rhododendrons, azaleas, camellias, acers and Pieris.

Well-rotted manure

well rotted
This is a soil conditioner and when dug into a bed or spread over the surface as a mulch, it slowly releases the nutrients it contains to feed plants’ roots. It also helps to make clay soils more free-draining and sandy soils better able to hold water and nutrients.

Sand and grit

These are useful for opening up heavy clay soils and making them more free-draining. Products such as Kelkay’s RHS Horticultural Silver Sand can also be added to John Innes composts if you are planting pots of drought-lovers, such as succulents or herbs, including sage and rosemary.

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