If you’re fairly new to gardening, you may well have been astonished at the number of different types of potting compost that are available from even relatively small garden centres and DIY stores, and you may be wondering what are the differences between them. This short guide should help you decide which one is best for you, and give you the confidence to go and buy compost for your garden.

Potting compost is defined as a medium in which to grow plants in pots or other containers. So it’s not really your home-produced compost, although that can work. Most people find it best to buy compost for container planting, as it contains a better balance of nutrients. But what sort should you buy?

Multi-purpose compost is probably most people’s go-to potting compost, and it’s pretty reliable for most plants. But do be aware that all multi-purpose compost is not the same, not even from the same manufacturer. Many of these composts were originally based on peat, but manufacturers are trying to cut down on its use, so are experimenting with different base materials. These can therefore alter year on year, as different and improved peat substitutes become available, or other materials are proven to be less effective as a growing medium. What’s more, multi-purpose compost doesn’t work very well for growing seeds, as the particles can be a bit big, and it can also dry out quite quickly.

 A good alternative is a loam-based compost, such as the John Innes composts. These do have a standard formula, developed by a gardening institute, and have different formulations for different purposes. They tend to be a bit more expensive than multi-purpose, but many people find that’s a price worth paying. The soil base means that they don’t dry out as quickly as multi-purpose compost.

Some multi-purpose composts now have “added John Innes”. This doesn’t actually have a defined meaning, but probably means that they also contain some loam and some added nutrients. This is likely to be a good thing, as loam dries out more slowly than most multi-purpose composts, but you may pay a lot more for that phrase, when you could achieve the same effect by mixing multi-purpose compost with some standard topsoil and adding slow-release fertiliser.

Specialist composts are used for plants that have specific requirements, such as ericaceous plants, which don’t like alkaline soils. They are generally not necessary for your average bedding plants and vegetables. Other specialist composts include mushroom compost and mushroom and manure compost, both of which are good for growing vegetables, as they contain plenty of organic matter. These may be more difficult to come by, but are available from compost suppliers.

So there you have it: a quick guide to potting compost!

First of all, blueberries like very acidic soil. Since most soil is more or less neutral, that means that most garden soil is not suitable, and you’ll therefore need to grow them in pots in ericaceous compost. You can buy compost from most garden centres and compost suppliers. When you first plant your blueberry, choose a container that is about 30cm in diameter, and be prepared to move it to a larger one in a few years’ time.

Secondly, although there are several types of blueberry that are marketed as ‘self-fertile’, some need another cultivar nearby. And whether self-fertile or not, your crop will be much better if you grow two different cultivars close together. This is not hard, as there are plenty of different varieties out there, but check the labels carefully to make sure.

Thirdly, you’ll need to provide food and water. Make sure the pot doesn’t dry out, watering with rainwater if possible. Of course in a drought, any water is better than none, but do try not to use tapwater if you can avoid it. Feed each month with an ericaceous fertiliser. The fruit ripens in stages, so you will need to pick it as it ripens. You may find that you need to net the bushes to protect them from birds, who seem to find blueberries almost irresistible.

Blueberries freeze very well, so you don’t have to worry if you can’t eat them fast enough. If you pop each picking into a freezer container, you can keep adding to it, and you will soon have enough for some great recipes. You can usually cook with them straight from the freezer, even if the recipe doesn’t specifically say that, although you may need to give cakes and muffins a bit longer than the recommended baking time to take account of the fruit being frozen.

Blueberry muffins are a really good use of frozen or fresh blueberries, and there are plenty of recipes out there. My personal favourite is Nigella Lawson’s recipe, because it is very quick and easy to make, but Paul Hollywood of The Great British Bake Off also has a good recipe on the BBC Good Food site. You can also add blueberries to pancake batter for both crepes or Scotch pancakes. It’s an excellent way of getting of your five a day, and with home-grown blueberries, you won’t even feel guilty about the cost!

Ericaceous compost is an acidic growing medium for acid-loving plants such as blueberries, rhododendrons, azaleas and camellias. Use it for suitable plants in pots, especially where your garden soil is alkaline.

Ericaceous compost is an acidic growing medium for plants that dislike alkaline, lime-rich soil. A lower pH means greater acidity; raising pH makes a soil less acidic. The name is associated with heathers (Erica).

Which plants is it for?

• Acid-loving shrubs: rhododendrons, azaleas, camellias and pieris.
• Fruit: blueberries, especially when grown in containers.
• Acid-loving heathers: Calluna and Daboecia. Not every heather needs acidic conditions.

A suitable ericaceous potting compost provides the growing conditions, nutrients and moisture retention these plants need. If your garden soil is alkaline, growing them in containers is usually more practical than trying to change the whole bed. Test your soil pH and check the needs of the particular plant.

Choosing bags: our peat-free ericaceous compost is offered in 40-litre bags, with pack choices from 1 to 50 bags. The product page shows current availability and pack options. Check delivery and access information before ordering.