The Best Compost For Hanging Baskets

Hello and welcome to another entry in DIY Gardening’s blog.

Hanging baskets can be a stunning and beautiful focal point in any garden, and while petunias, begonias and fuchsias can all produce long and eye-catching trails, they need a specific type of compost.

In this post, I’ll answer the following questions:

What is the best compost for hanging baskets?

What are the key ingredients, and what’s their purpose?

Why is peat used, and are there more environmentally-friendly composts that work just as well?

I’ll also reveal the four ingredients I put into my peat-free compost mixes to get amazing results with less fertiliser and less frequent watering.

The Key Ingredients in Hanging Basket Compost

There are two problems that gardeners come up against when growing long trailing or bushy plants from hanging baskets:

1. The baskets dry out very quickly in the sunlight and need lots of water.
2. The excess water flushes the nutrients from the compost.

Plants grown in dry and/or nutrient deficient compost generally perform poorly.

To remedy this, the compost should ideally comprise:

Peat (optional) – while not environmentally friendly, there is a reason why all the popular compost products contain it. Peat is the perfect growing medium, it retains moisture as it can hold several times its weight in water. It also absorbs nutrients from the fertiliser, meaning they are less likely to be flushed out of the basket when it’s watered.

Coco coir – made from the husks of coconut shells, this coir is gradually replacing peat moss in many commercial compost mixes as it’s more environmentally friendly. A good hanging basket compost should contain at least some coco coir.

Wood fibres – wood fibres help with drainage, also aerate the mix and provide space for the roots to grow.

Slow-release fertiliser – because hanging baskets are watered so frequently in the summer, the nutrients are flushed out quickly. Slow-release pellets can feed the plants in the baskets for between 4 and 6 months.

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My Hanging Basket Compost Mix

I’ve been trying to reduce my use of peat-based products as they’re terrible for the environment, so for my hanging basket compost, I use:

General-purpose peat-free compost – I buy locally and get it delivered. My preference is woody, coarse compost that’s not too fine.

Coco coir – I purchase this online and get it delivered. It’s very lightweight and comes in bricks that need to be soaked in water; the coir then expands and can be added to the compost mix. Coco coir holds onto nutrients in the same way peat does, and it holds moisture and aerates the mix too.

Slow-release fertiliser granules – A large bag of these lasts a long time, and they can be used next year as they store well. I add these to the mix so I don’t have to use liquid or other types of fast-acting fertiliser, which wash out easily.

Water storing gel or vermiculite – The gel is preferable as it breaks down and degrades after a few years, but it’s more expensive. Both are designed to soak up moisture and release it when the compost starts to dry out, making them the perfect addition to hanging baskets compost.

Never tried vermiculite? This guide explains the difference between perlite and vermiculite.

Here are the ratios I’m currently using:

Peat-free compost: 50%

Coco coir: 45+%

Slow-release fertiliser pellets: ~2.5%

Vermiculite/moisture control gel: ~2.5%

Why I’m Cutting Down On How Much Peat I Use

Peat has been used in horticulture and industrial farming for hundreds of years but isn’t sustainable.

It takes many thousands of years for peat bogs to form, often at a rate of no more than 1mm per year, and they store a vast amount of carbon which is released when they are dug up.

To date, over 15% of the world’s peat bogs have been drained, and it’s obvious that if this continues, our environment will be adversely affected.

Not all of the peat is used in domestic horticulture, with a considerable amount used for fuel and commercial farming, but the tide is turning against peat.

The best performing compost for hanging baskets is, in my opinion, one that contains peat, hence why most commercial compost manufacturers are hesitant to remove it from their mixes fully.

That doesn’t mean you can’t make your own peat-free compost mix that will work very well in a domestic garden.

You can learn more about peat and peat-free alternatives on the RHS website.

What Happens If You Use Regular Compost?

Regular compost can indeed be used in hanging baskets, it just won’t be optimal and may:

• Dry out quicker.
• Need more frequent watering.
• Require more fertiliser.
• Become compacted more easily.

As specialist composts and home made DIY mixes only cost fractionally more, there’s no reason not to use an optimal mix, especially if you’re out at work all day and won’t be able to water the baskets as often.

Update 2021:

Unsure which plants are best suited to hanging baskets?

Try our guide to stunning hanging basket plants that make an unforgettable statement.

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