How to Choose The Best Multi-Purpose Compost
Compost is organic material that can be added to plants to improve their health. Whilst making your own compost is a great option for reducing food waste, pre-bought bags can help anyone get started with composting.
Multi-purpose compost is versatile and suitable for most gardens, it generally provides all the nutrients your plants need for healthy growth. Whilst multi-purpose compost tends to be a good all-rounder, there are other types available to suit specific soil types and plants – worth bearing in mind before you make a purchase.
If you reckon multi-purpose is the way to go, there are just a few things to bear in mind when looking for the best compost for your garden:
Benefits of Using Compost
Whilst we all know that compost is good for plants, it may not be so obvious as to why.
Seeing as compost is made up of decayed organic material, it has a lot of great nutrients in it. The three main nutrients, which are often present in shop-bought fertilisers as well, are nitrogen, phosphorous and potassium.
Using compost helps improve the condition of the soil, and help with pH imbalances. It also works to maintain moisture levels and boost the general health of plants.
Another benefit is that the microorganisms introduced to the soil will also help your plants to repel a number of plant diseases.
Compost can often be used at many different intervals along the life of your plant, from encouraging seeds to germinate, to aiding with repotting plants, or persuading plants to flower.
Of course, composting is also good for the planet. Creating compost at home in a compost bin is a great way to recycle kitchen and garden waste.
Ingredients in Compost
Multi-purpose composts contain a range of nutrients and minerals to help plants thrive. However, you should note how long the compost will continue to nourish your plant for. Most multi-purpose composts will provide nutritional value for around three months.
The key ingredients to look out for are nitrogen, phosphorous and potassium. Broadly speaking, nitrogen helps with leaf growth, phosphate is for a strong root development, and potassium will encourage flowering and fruiting.
Sometimes there will be additional ingredients like seaweed; seaweed contains a lot of micronutrients that are beneficial to both the aesthetic appearance of the plant and its general health.
There may also be other materials present, like bits of bark or stones. This can vary from compost to compost. The inclusion of larger materials can stop the compost from becoming too compacted, and can help with drainage and aeration. However, it can also just demonstrate that the manufacturer isn’t very careful with sieving the compost, and it’s not uncommon for budget composts to have a higher density of large material.
Finally, whether or not compost contains peat is a matter of interest, and contention, for many gardeners. Given that it’s such a polemic issue, you’ll find that the next section is dedicated to the pros and cons of peat-based compost.
Peat vs Peat-Free Compost
Traditionally, a lot of composts contained peat – it’s high in nutrients and works wonders on plants. However, the negative effects of harvesting and using peat have become more evident in recent years.
First, a little background on peat, in order to truly understand the problem. Peat is made from partially decomposed bog plants – that’s why it’s so nutrient rich. These plants have been compressed down which locks up all the carbon that they’ve absorbed in order to grow. Peatlands can actually store and absorb a lot of carbon dioxide, keeping it out of the air. Ultimately, they do a valuable job towards helping with climate change.
When peat is dug up, to be used as compost (or for other reasons), the store of carbon is disturbed and released into the atmosphere. This is the first downside of harvesting peat – especially on a commercial scale.
When peat is spread over the garden, its carbon content turns into carbon dioxide over time – not great news when trying to keep the release of greenhouse gasses to a minimum.
Finally, peat bogs offer a unique and rich ecosystem for lots of animals. Once this environment is disturbed, it is extremely difficult to recover it. Due to the way peat is formed, it is very hard to recreate or restore a peat bog.
So, where does that leave us with compost?
Well, peat-based compost is still readily available, but a lot of gardeners are choosing to avoid it as much as possible for the above reasons.
Many manufacturers are attempting to lower the peat content in their compost, due to its negative impact on the environment. However, if the compost doesn’t state that it’s ‘peat free’ or at least ‘low in peat’, you should presume that it has a high peat content.
There are a range of peat-free composts on the market, although some gardeners feel they are not as effective as those containing peat. Those that are peat-free generally contain wood-based materials such as wood fibre, sawdust or bark.
Peat-free organic composts also tend to be more expensive because there is more processing involved than simply digging up peat.
Now you have the facts, you can make your own informed decision about compost. In the end, whether you choose a compost which contains peat or not will likely come down to your own priorities.
How Much Compost to Buy
Compost can come in some pretty large sacks, some of which may well be too large for standard gardening jobs.
The composts featured on this page come in bags ranging from 50 – 70 L. For context, a 50 L bag can weigh 12 kg + (it depends somewhat on the composition of the compost).
Whilst a lot of composts are sold in 100 L bags, these may not be practical for some people in the garden. They can weigh anywhere from at least 25 – 30 kg.
A lot of gardeners find 50 L bags a lot more manageable, although of course they may not offer such good value for money.
The most important thing to be aware of is not buying a bag that will be completely impossible to move. Even though a lot of delivery drivers will be helpful enough to carry the sack to the back gate or shed, you will likely still have to carry it some way yourself.
While compost can be stored indefinitely, it does begin to lose some nutrients after four months. After one year of storage, the compost may be sufficiently lacking in nutrients to make it not worth using. Therefore, it’s a good idea not to buy more than you need.
Multi-Purpose Compost FAQs
Why should I use compost?
Compost is nutrient-rich, which means it’ll help improve soil structure, boost strength in your plant so it can fight diseases, and encourage your plants to produce vibrant and healthy flowers. It should also help retain moisture in the soil, meaning each water should last for longer!
How long does compost last?
The longer compost is stored, the more nutrients it loses. After one year it will have lost a lot of its nutritional value and may be less worthwhile to use in the garden.
Storing compost correctly can stop it from getting too wet or dry, which are other issues that can result in compost not lasting as long. If it is shop-bought compost that came in a bag, make sure that the bag is well sealed for storage.
How do I use compost in my garden?
Compost can be used in a variety of ways; in its simplest form, it can be simply raked into soil and spread near plants. Finely-textured compost can even be sprinkled over newly sown grass seed on the lawn.
- If you want to sow seeds in a tray, you can use compost as the potting medium to give them a boost. Plant the seeds according to their instructions, and water the compost after sowing them.
- For repotting, use compost to fill in the space between the plant’s roots and its new larger flowerpot.
- For growing cuttings, fill a pot with compost, make holes using a dibber, and place the cuttings in the holes, pressing the compost around it. The process of taking cuttings from plants can vary, so check that you’ve followed an additional instructions before planting the cutting in compost.
- Compost can also be used as the potting medium in hanging baskets.