Which compost should I buy?

If you go down to the garden centre today you’re in for a big surprise! Easter is the first weekend of the year that everyone starts to think about their gardens and what to change and what to plant … so you won’t be alone!  

There’s no rush, however .. anything tender can’t be planted out until May, when the threat of a frost has gone and it’s best to do some thinking and preparation first before any other planting. The best two times to plant are spring and autumn, and the spring planting window is open until the end of June – so take your time!

One of the items you will more than likely buy at the garden centre is compost.  I am often asked which compost to buy, and it can be very confusing as there are a multitude of composts available. But what actually is compost? Essentially it’s a growing medium made from the decomposition of organic matter, sometimes with extra things added in.  Because it’s mainly made from decomposed plant materials, it can add nutrients into your soil, acting as a boost or fertilizer for your plants.  If you’re not sure what to get for what purpose here’s my guide to composts:

Homegrown compost – you may have a compost bin or storage area where you throw all your cuttings, grass clippings, vegetable food waste and maybe even shredded paper.  Homegrown compost needs to be turned regularly as it naturally breaks down.  Eventually it will make a crumbly brown substance that has no smell, that you can add to your flowerbeds and vegetable patch as a nutrient boost.

Multi-purpose compost – is the most common compost you’ll find at the garden centre and that’s because it can be used for a variety of uses. Its base can be peat or other products such as coir. This is the one you need if you’re making up pots, containers or hanging baskets for the summer. Its nutrient value is fairly short-lived, so you’ll have to feed your plants with fertilizer to top up the nutrients for their continued lush growth and flowering, it also dries out fairly quickly so keep an eye on it and water when required.

Seed compost – is generally finer than multi-purpose compost and has less nutrients in it as it is a growing medium for seed sowing and seeds have all the nutrients they need to get going inside them. I’m trialling using seed and multi-purpose to grow sweet pea seeds this year to see if there is any difference in their growth as lots of gardeners use multi-purpose for seed sowing and are more than happy with the results.

John Innes compost – John Innes is a brand, but their composts are based on loam or soil so tend to not to dry out as much as those based on peat or its alternatives.  There are much as those based on peat or its alternatives.  There are different types of compost for different uses, but each has been scientifically developed especially for each use. They tend to be a bit pricier, but it may be wise to choose a loam-based compost for any plant that you want to live for a long time in a pot.

Ericaceous compost – is compost for acid loving plants such as rhododendrons, camelias and blueberries. If you remember your pH Scale from school, you’ll know that all elements can be tested to see if they are alkaline – neutral – acid.  Some plants like particular parts of the pH scale and a good indicator of how acidic your area is by whether there are many of those plants thriving in gardens or woodlands. Use ericaceous compost in a pot to grow these plants if your own soil conditions are not suitable. There are also ericaceous fertilizer to give plants in pots or in the ground a boost.

Peat-Free compost – whichever compost you’re buying I urge you to buy a peat-free version.  We’ve been increasingly removing and using peat from its natural habitat for the last century, which we now know understand has a detrimental effect in a number of areas.  

Research shows just how important peat is to not just our local landscapes but to our whole planet. It acts as a store for huge amounts of carbon, it's a great habitat for very specific wildlife and it also plays an important role in water management.  

In 2011 the Government pledged to phase out use of peat in garden products, and you should only now be seeing peat-free or reduced peat composts and I urge you to buy them. Yes, they are a bit pricier but I’m not sure we can justify using the peat versions anymore now we know the impact they have.  

For lots of practical gardening advice, get in touch with The Girl Who Gardens!

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