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SUSTAINABILITY | Read Our Commitment
Please read on to find out what the best organic fertilisers are, what to buy and when to use the different options. As a producer/supplier, no surprise, our quick answer to the question is our Biochar Super Compost (SF60).
The internet is littered with poor use of terminology and in a lot of cases a fertiliser that is labelled organic may not actually be organic, therefore we have gone back to basics to cover some core definitions before we get stuck into the list of organic fertilisers. If you are sure of your terminology, jump down a few paragraphs.
What does Organic mean?
Hence an organic fertiliser has to support these requirements. The term 'organic' excludes most "man-made" or "synthetic chemicals".
Here at SoilFixer we find these definitions tricky.
Let us look at the term 'man-made' using compost to illustrate. Compost is widely reported as the number one natural organic fertiliser, it is rarely considered man-made. SoilFixer's history is based on making compost - we are die-hard advocates of quality composting. But look at this another way: all the compost available for purchase is "man-made". Each city/region has huge composting sites that accept truckloads of green waste collected from our gardens. It is then shredded in enormous shredders to create piles (windrows). Then pile conditions are controlled (time, temperature, moisture) using huge diggers to turn it. finally, the compost is sieved and bagged. The microbes do all the decomposition - totally a natural, organic system, but making compost is a man-made, large scale recycling process that uses energy. The 'energy' and 'man-made' process is true for just about every organic fertiliser you can buy. (e.g. bonemeal - a high-temperature process to sanitise and crush animal bones; chicken manure - dried, pasteurised, packed in plastic tubs, transported to garden centres, seaweed, etc).
Synthetic - usually means not made by nature. Synthetic is often applied to fertilisers and in particular NPK fertilisers with a negative connotation. Again the terminology is 'tricky'. If we go back to school for a moment, one of the foundation stones of natural science is that we cannot create or destroy matter - all we can do is change its formulation. There is the same number of nitrogen atoms on earth today as there have always been. (Man cannot make new nitrogen atoms). All nitrogen fertilisers are made from naturally occurring nitrogen (i.e. nitrogen from the air) which is converted to an ammonium compound using lots of energy (the Haber-Bosch process). All nitrogen added to soil is cycled back into the natural world via the nitrogen cycle.
Rather than 'man-made and synthetic are bad', maybe a more nuanced context is needed to help tackle the valid and real concerns about the future of our planet.
We cannot avoid the fact that in heavily cropped soils (be they allotment or farm), depletes the soil of NPK nutrients (they are taken away in the crop). These have to be replaced each year to maintain yield. We tend to blame the synthetic atom of nitrogen as harmful and yet the natural atom of nitrogen (e.g. attached to compost particle) as 'OK'. Again the problem is not nitrogen - the problem is how do we maintain the soil organic matter when using nitrogen. Without doubt, long term use of compost and an organic system achieves this. But, what if we could also achieve the balance by applying man-made (!) nitrogen without harming the soil humus.
SoilFixer is agnostic around the sources of NKP. If renewable energy was used to make NPKs, they are applied correctly, and we understand that we also need to add/maintain soil organic matter just as much as we need to add NPKs, then new solutions are possible.
Many gardeners have got used to using man-made NPK chemical fertilisers (i.e. compounds with high nitrogen, potassium, and phosphorous content). Many are converting to 'organic fertilisers'.
We have copied over a number of "eco-friendly alternative organic fertilisers". Below each, we have added a cautionary note for gardeners to think about.
There are many types of compost. Here, we will focus on compost made on a large-large scale from green waste. (This would also cover all homemade compost).
By far one of the best organic additions you can add to soil. But here's an interesting side thought - although it releases some NPKs slowly over time, it is sold (labelled) as a soil improver. It is not sold (labelled) as an NKP fertiliser because it does not meet the "legally defined" minimum level of NPK for a fertiliser!
Where possible - make your own compost. You know exactly what goes in it. If you are buying compost - just be aware you need to read the label. Compost some years ago used to mean peat - that's all. Now some branded composts contain no green waste and no peat! They are mixes of wood, coco coir and the like. Fine, they work well but have a think - in the UK we grow no coconuts. All coir is imported. In theory, using it we have prevented the destruction of peat wetlands in the UK and Ireland. But we have transferred the responsibility for a sustainable compost to the far side of the world. So maybe ask the question - is the coir in the compost as a result of the massive move to make cocoa milk or palm oil tree planting - both of which we now leaning have come at an enormous cost in terms of destruction of rain-forest.
We copied this from a leading blog on organic fertilisers: "Kelp-based fertilisers contain potassium and a little nitrogen but the true benefits are the long-term effect they can have on your plants. Kelp has been shown to stimulate soil development, which in turn enables plants to thrive and increases overall yield. While you can buy kelp in garden centres, the cheapest way to get your hands on some is to gather and compost it yourself".
Please mull over this paragraph. If we all go down the seafront and gather kelp (seaweed) - we will destroy the habit. If 'farmers' (i.e. the kelp fertilisers suppliers) cut too much kelp they will destroy the natural habitat. Like any other natural resource, it has to be farmed in a sustainable way, otherwise, we are no further forward. Cutting, drying, grinding, packing and transporting seaweed fertiliser has similar energy demands as making nitrogen chemicals. (Economics - the price per tonne of a product can be a very good tool for analysing the sustainability of a product. A huge part of the cost to make and deliver a product comes from the energy consumption (diesel for transport, electricity for heat and power), human labour (all workers need wages to pay for food and heating), purchase of machines (which comes down to making metal and concrete which comes down to heat/energy).
"The most commonly used type of manure is cow manure (followed by chicken, pig and horse). Manures are rich in nutrients that feed plants and soil alike. As with chicken manure, applying fresh directly to plants can burn them, so you have to properly compost it before use. If you’re using it on fruit and vegetables, it’s worth searching for manure produced by organically farmed cows, otherwise, you risk putting chemical antibiotic residues, among others, on your plants". A verbatim copy of other websites.
Consider this - cows in a field poop on grass - this is not collected and available for use. All cow manure available for use is from cows kept in sheds. Almost all cows need to be sheltered during winter. When using organic manure, the welfare aspect of animals can be of equal or greater importance. Do not assume natural-organic is good - you may also need a certification that covers animal welfare.
We would only recommend the use of cow manure when it has been properly hot composted. (High temperatures of 60C will kill pathogens (sterilise) and breakdown any residual antibiotics. Leaving it to stand in a pile in a filed for a year sadly often results in an anaerobic process, with loss of nitrogen (as ammonia gas) and the production of methane (240 times as potent as a greenhouse gas). So again, do not buy it because it is 'organic' not because it is cheap - we suggest you buy it because it has come from the farm which cares for its animals and processes the manure in a diligent manner to create a valuable product.
Chicken poo contains more nitrogen, potassium and phosphorous than any other type of manure and it’s a great source of other nutrients such as calcium and magnesium to boot. The manure can be bought in pellet form or you can ask a friendly farmer for leftover chicken muck and compost it yourself. However, you must make sure that the manure is properly composted before use as the high nitrogen content can burn plants if the manure is raw. Also, as Raskin points out, make sure that your fertiliser comes from a free-range chicken farm in order to maintain the organic and nutritional value. And yet, because it smells, it is almost always supplied in a re-sealable plastic tub that will rarely get re-used or recycled. Being green is not easy!
Alfalfa meal is another plant-based fertiliser that benefits the garden in subtle ways, although it does contain a decent amount of nitrogen as well as some potassium and phosphorous. Alfalfa’s real benefit is that it helps improve soil quality and enables the production of more nutrients for plants to feed on, which increases plant growth over time. It works particularly well on roses and can be bought from most garden centres. Keen supporters of cover crops, but you know from above, the processing plant material into a fertiliser is energy-intensive, etc.
Limestone fertiliser is usually a healthy addition to the soil but benefits differ depending on the source of the stone. Used to balance pH levels in soils with high acidity, limestone also contains calcium, which helps with overall plant growth, and magnesium, which encourages stronger, healthier plants. With limestone fertilisers, it’s important to test levels of acidity in your soil to determine how much, if any is needed before application. Limestone rock requires mining and transport from mine to your garden. It is a huge energy-intensive operation. It might be natural but it can be argued it is every bit as man-made as other fertilisers. Healthy soil will maintain a healthy pH. Rarely does a soil lack calcium and any calcium plants take up can be returned by composting and adding compost back to the soil.
In conclusion, the arguments for and against organic fertilisers are subtle and there is often no clear right or wrong. We advise you to make compost at home. If you have to buy additional fertilisers and compost - then just beware. Try and read the labels and choose a supplier with solid ethical values and environmental commitments.
If you want to boost soil fertility look at newer options such as the role biochar can play. You can make your own biochar super compost by adding our compost humification agent to your home compost waste.
Biochar Super Compost (The best soil improver, enriched biochar, code: SF60)Jumpstart microbia..
£24.99
