Widgets Blog - Emma the Gardener

Sow, Grow, Repeat: Composting

View comments

I hopped up to London a while back to be a guest (along with Jeff Lowenfels, author of ‘Teaming with microbes’) on ‘Sow, Grow, Repeat’, the Guardian’s gardening podcast. Wearing my Master Composter hat, I was chatting with Alys Fowler and Jane Perrone on the ins and outs of composting. Find out more about Bokashi, the weird things compost nuts add to their heap and the microbes living in there!

From the Sow, Grow, Repeat website, you can listen to the show online, download an mp3 or subscribe to the show via iTunes.

Posted in Blog on May 30, 2015 ·

Last modified on Aug 9, 2015

Tag: compost

Starting over: composting

View comments (1)

Kitchen waste set aside for home composting

I’m a firm believer in composting. In the years in which I haven’t really had a garden, I have mourned the loss of valuable resources as I sent my compostables off in the municipal collections.

Making your own compost is a wonderful way of feeding your garden. Closing the circle, turning a waste product into something useful, and saving money into the bargain.

Secret heap
A stealthy compost bin, hiding behind a tree

One of the things I have done this year, in my new garden, is set up a compost bin. It’s not in an ideal location – it’s not close to the house, so I have to make an effort to go out there. And it’s currently in the shade, although the removal of an unwanted conifer will soon sort that out.

And so I am, once again, collecting up compostables in a separate pail. Vegetable scraps, tea bags and cardboard tubes for the most part. Cardboard tubes (or scrunched up newspaper, or corrugated cardboard) are a valuable addition to the heap. Not only are they carbon-rich, balancing out an excess of nitrogen-rich kitchen scraps or grass cuttings), but their shape adds air to the heap. Composting bacteria need oxygen, just like us.

Cold composting
The current contents of my cold compost bin

Wearing my Master Composter hat, I went to London recently to join Alys Fowler and Jane Perrone for a chat about composting. You can hear the result in the latest episode of Sow, Grow, Repeat, the Guardian gardening podcast.

Did they leave in the bit where Alys talks about composting her pants? You’ll have to listen in to find out!

I do CAT cold composting where I add a mixture of materials to my heap as and when I have them. It may take longer to rot down, but it’s a lot less effort than looking after a ‘hot’ heap ;)

Posted in Blog on May 30, 2015 ·

Tag: compost

The Composting Condundrum

View comments

Compost heap
A giant compost heap, like this one at West Dean, isn’t an option in my new garden

Clearing the allotment is no simple task – it’s now a 20-minute drive away, and as the weather has turned wet and the ground is sodden, it’s impossible to get the car anywhere near the allotment. Anything I want to bring home has to be carried down to the car park, and transported from there. As a result, there has been a certain amount of prioritising about the things that are worth rescuing, and those that can be passed on to the new tenant (whoever that will be).

I have three plastic compost bins on the allotment – two standard green hand-me-downs that deal nicely with garden waste, and a ‘Green Cone’ composter. The Green Cone is designed to deal more with food waste, even meat, and to keep it safely out of reach of rodents inside a buried basket. Unlike a regular composter, you don’t harvest compost from a Green Cone, it feeds the soil around it and occasionally you would need to move it as the basket fills up.

The Green Cone compost bin on the allotment

The question is what sort of composting I want to do in the new garden, and where to site the bins. It’s not a question of composting or not – as an organic gardener I would feel very remiss if I weren’t composting at all, and although most people think that sending off their food waste to be recycled is a good thing, I see it as sending away nutrients I have paid for that could feed my garden!

In the previous house I had two plastic ‘daleks’ at the end of the garden, and two worm compost bins that lived in the shed. One of those was abandoned when I moved out; the better of the two, my ‘Can-o-Worms’ is, I think, in Malvern. Worm composters need some shelter – like us, composting worms don’t like extremes of temperature. They need shade in summer and protection from freezing weather in winter. And rain, because worms can drown if the bin fills with water.

In the main body of the garden, the obvious spots for compost bins are out of sight, and hence in shade. I could put one in the ‘extension’ where it would be less obvious, but it would also be further from the house. Given our more rural location, rodents are likely to be more of a concern, and I think the worm bin (which is up on legs) might be a better bet than the Green Cone. We don’t produce a lot of food waste that would be unsuitable for normal composting, and I can still send that off for municipal recycling.

Worm composter
My worm composter might be a bit cleaner now, after a year off in Malvern!

The answer might be to build a shelter for the worm bin, and have that out of sight under the kitchen windowsill, where it will be in shade, and a regular compost bin elsewhere in the garden. Something more attractive than a plastic dalek would mean it could have a better location – but one of those posh wooden ‘beehive’ composters isn’t going to fit in very well with my idea for a ‘Middle Eastern’ theme. I’m trying to think of something else that might do the job, or someway I could give a compost bin a suitable makeover!
So it seems that the compost bins on the allotment could safely be bequeathed to the new owner… but nothing is decided, as yet.

What do you think?

Posted in Blog on Nov 25, 2014 ·

Tags: compost & gardens.

Space worms

View comments

Worms were the only survivors when space shuttle Columbia broke up on re-entry in 2003. Caenorhabditis elegans, nematodes, had been sent into space to test a synthetic nutrient solution. Their naturally short life-span meant that the survivors were several generations removed from the worms that were blasted into space at the beginning of the mission. Nematodes experiments have also been conducted on the International Space Station (ISS), looking at the effect of microgravity – it turns out that these worms can suffer muscle mass loss in the same way as humans do. Nematodes weren’t the only worms included on that fateful mission; among the student experiments (which included space bees) was one that aimed to investigate mealworms (Tenebrio molitor). Sadly they didn’t survive.

Worm compost
Composting worms, at work on Earth

Small organisms such as these are very useful for bioscience research in space, but there are other reasons why worms might be a key feature of future space adventures. When the latest Antares supply mission to the ISS suffered a ‘launch mishap’ at the end of October, another student experiment – to investigate whether worm composting works in space – went up in smoke. The students wanted to find a way to recycle leftover astronaut food, and were sending composting worms (Eisenia fetida) into space – the same worms you’re using here on Earth if you have a worm composter. Fortunately, the students have been told they will get another chance to run their experiment.

Composting worms can help to dispose of waste food because they can eat things we can’t, and including animals and insects into closed-loop agricultural systems in space is one way of completing the cycle and turning waste products into inputs. They can be used to improve the soil and produce fertiliser (like the composting worms) or to turn inedible biomass into protein to enhance the astronaut’s diet. But adding animals into the system can be tricky – not only are they large and heavy (hence expensive to launch into space), but they produce waste gases and some of them would stink out closed quarters. Plus you have to factor in the time spent looking after animals, when astronauts are already busy. Aquatic animals such as fish are also being considered, but bring their own set of problems to overcome.

And so the idea of raising edible insects in space arises. These ‘microlivestock’ can be easily and cleanly raised on waste products, and produce little in the way of waste themselves (and frass , worm poop, makes good fertiliser). Insects are already eaten in some cultures on Earth, although for most people they are decidedly not on the menu.

Main course
An appetising plate of edible insects

Two of the most studied species are silkworms (Bombyx mori) and mealworms, which are beetle larvae.

Katayama et al point out that insects were an important portion of the hunter-gatherer diet. Perhaps the Paleo diet people should be taking a look….

Silkworm pupae
Yummy looking silkworm pupae

Yang et al write about the history of silkworm consumption in China and state that silkworm culture won’t have adverse effects on the cabin environment. They also say that silkworm fibre (I assume they mean silk) is over 98% protein and could be hydrolysed into an edible product. I’m not sure anyone would find that more appetising than the worms themselves.

Yu et al propose a simple bioregenerative life support system involving mulberries and silkworms. The mulberries would provide fruit for astronauts, plus leaves to feed silkworms. The silkworms could also eat the leaves of stem lettuce – stem lettuce is a popular Chinese vegetable, but the leaves aren’t eaten (and seem to be considered inedible). 105 silkworms would provide the daily protein requirements for an astronaut (a Chinese astronaut, or taikonaut – they note that the Russians have double the protein requirement!). The silkworms can be eaten as pupae or as powdered larvae (which has the advantage of not having to deal with cocoons). Yum.

Beyond that being a slightly dull diet, I fail to see how mulberry trees would make good candidates for space cultivation, being large trees. You could take seeds, I suppose, so they blast-off weight would be small, but then you’d have to wait years for the trees to mature….

“The height and diameter of ground-controlled mulberry tree were much lower than other kinds of fruit trees. Lower trunk shortened the distance of transporting nutrient and water, accelerated the growth of branches and leave and improved the efficiency of photosynthesis.”

Li et al note that silkworms have a limited waste disposal role, as they only eat the leaves of stem lettuce and mulberry leaves. They investigated mealworms as an alternative, feeding them wheat straw and vegetable waste (and wheat is one of the ‘big 3’ cereal crops on Earth that produce most of our calories, so being able to grow it in space would be useful). Mealworms can be fed a variety of plant material.

Mealworms, with a side of mole crickets

And earlier this year, three volunteers spent three months inside Moon Palace 1 (Yuegong-1), an artificial biosphere in Beijing designed to test the kind of life support system that may one day be used for a long duration space mission. They grew grain, vegetables and fruit and fed the crop wastes to mealworms. They ate dozens of worms each day, trying out different cooking styles and seasonings. No doubt we can expect them to publish a cookbook very soon!

Mealworms may not be the best choice, though – the HI SEAS project decided against them as they are “little escape artists”, something I have personal experience of. I used to have a regular delivery of live mealworms to feed the garden birds. I can just imagine how the postman felt when he delivered the damaged box from which they were all escaping…. Some scientists feel that freshwater algae could deliver the same benefits, but that’s a topic for another post :)


Katayama, N., Yamashita, M., Wada, H., & Mitsuhashi, J. (2005). Entomophagy as part of a space diet for habitation on Mars. The Journal of Space Technology and Science, 21(2), 2_27-2_38.

Kramer, M. (2013). How Worms Survived NASA’s Columbia Shuttle Disaster. [Online]. Accessed 9th November 2014.

Li, L., Zhao, Z., & Liu, H. (2013). Feasibility of feeding yellow mealworm (Tenebrio molitor L.) in bioregenerative life support systems as a source of animal protein for humans. Acta Astronautica , 92(1), 103-109.

Rutkin, A. (2014). Space hopefuls dine on worms in ‘Moon Palace’ module. New Scientist. [Online]. Accessed 9th November 2014.

Space Today Online. (2006). Tragedy of Space Shuttle Columbia. Space Today. [Online:]. Accessed 9th November 2014.

Yang, Y., Tang, L., Tong, L., & Liu, H. (2009). Silkworms culture as a source of protein for humans in space. Advances in Space Research, 43(8), 1236-1242.

Yu, X., Liu, H., & Tong, L. (2008). Feeding scenario of the silkworm Bombyx Mori, L. in the BLSS. Acta Astronautica, 63(7), 1086-1092.

Posted in Blog on Nov 8, 2014 ·

Last modified on Aug 10, 2015

Tags: space & compost.

Groundbreaking food gardens

View comments (4)

On 4th June 2012 I received an email from Niki Jabbour, a garden writer in Nova Scotia in Canada. She said that she was working on a book of edible garden plans and would like me to contribute a design for a composter’s garden. Niki continued on her quest to collect interesting plans for food gardens from writers and bloggers around the world, including Amy Stewart, Roger Doiron, Amanda Thomsen and our very own VP.

A month later, I sent her my idea – the Circle of Life garden. As you can see, my artistic skills are in need of some development:

Emma Cooper's Circle of Life garden design

The idea behind the Circle of Life garden is that it is fuelled by returning waste products to the soil. Chickens have a run around the outside, where they can be fed any suitable garden waste (and will help with pest control). Their coop is right by the compost bins, where their poop will make the composting process go with a bang. A rhubarb patch soaks up the nutrients right by the compost bins, and there’s plenty of garden beds to make good use of all that lovely compost.

To find out more you’ll have to buy the book. Niki has done a lovely job of writing up my idea, and a small team of illustrators have turned all of the designs into beautiful, instructive illustrations. They’ve really brought all of the gardens to life.

One feature of my design that caused a bit of a stir was the comfrey tower. It’s a simple system that uses a vertical length of tubing to rot comfrey leaves down into a liquid feed without that pesky stench. I didn’t attempt to draw one; Elayne Sears has done a lovely job with the image:

Comfrey tower

Illustration courtesy of Storey Publishing, © 2014

To recreate the Circle of Life garden in your own back yard, you’ll need a copy of Groundbreaking Food Gardens, which is available now. When you buy one you’ll also get 72 other wonderful edible garden plans for free ;)

Posted in Blog on May 10, 2014 ·

Tags: books & compost.

Bored with Card

View comments (1)

This opinion piece was first published in the June 2011 issue of Kitchen Garden magazine. Things haven’t changed much since then ;)


Although the world keeps changing far more rapidly than many of us can keep up with, there seems to be at least one constant in modern life – much of it comes wrapped in cardboard. It’s almost impossible to buy anything without having to peel off several layers of packaging, and if you don’t have access to decent recycling facilities then a good deal of your bin gets filled with cardboard every week.

On the face of it, this can be a boon to gardeners. We can get our environmental brownie points by taking all that cardboard waste and using it as a carbon-rich material to help us turn our kitchen waste and grass cuttings into life-enhancing compost. By doing so we cut down on the amount of rubbish going to landfill, the fuel used to get it there and the nasty methane gases it makes when it rots down underground. We can be smugly virtuous and bring home our groceries in abandoned cardboard boxes, then turn them into plant fuel – ditching the plastic bags and saving ourselves a packet into the bargain.

Except… it’s not the simple, is it? The boffins that design this packaging are gradually making it all completely indestructible. If you build your heap carefully, nurture it, turn it and then wait several months for the compost to reach perfect maturity then when you come to use it you’ll find that all that innocent-looking cardboard has been contaminated it with plastic.

There’s the cardboard lids from take-aways, and paper plates from picnics; they both have a thin layer of plastic in the mix, which is left behind when the card rots away. And those paper cups you chose for the allotment get-together, precisely so you could compost them? They’ve been coated with something that prevents them from degrading at all. They come out looking, at most, slightly squished.

And although it’s perfectly possible to buy a well-known brand of tape (at least here in the UK) that’s made from cellulose (the same stuff plants are made from) and that disappears without a trace on the compost heap, you’ll find that most companies use plastic tape that just clumps together in a horrible mess.

You’ll have less trouble with plain corrugated cardboard, and it even adds some air into the mix, which can only be a good thing – but watch out for the glue strips used to hold boxes and parcels together, as you’ll be fishing them out later if you don’t.

Clearly eternal vigilance is necessary if you want to keep your heap uncontaminated – which is fine for old hands and composting ninjas, but how to we get people into composting when it’s no longer as simple as ‘cardboard good’, ‘meat and fish bad’?

Compost sticker

Have you read these?
Learn to love leaf mould
Dig deeper, the archaeology of the compost heap

Posted in Blog on Nov 2, 2013 ·

Last modified on Aug 10, 2015

Tags: compost & environment.

Learn to love leaf mould

View comments (1)

Fallen leaves

There might be a new chill in the air, but autumn is a beautiful time of year, when the leaves change color on the trees and the sun shines through a million little stained-glass windows. But once the leaves fall to the floor then it’s a different story. If they fall into ponds they can foul the water, on the lawn they can cause bleached patches and they make paths slippery in the winter. Gardeners everywhere spend the autumn raking up leaves to prevent these problems, but did you know that you can turn them into free soil improver for your garden, rather then sending them off with the rubbish?

Leaf mould is known to horticulturalists as a low fertility soil improver, meaning that it’s great for improving soil structure, helping to improve both water retention and drainage and promoting a healthy environment that helps plants to thrive. Leaf mould makes an excellent mulch, suppressing weed growth and evaporation whilst the earthworms work hard to incorporate it into the soil for you. You can also use it as part of a home-made potting mix, perfect for raising seedlings – try equal parts of leaf mould, loam and garden compost for a good multi-purpose potting compost.

And if you have bare soil in your beds over winter, considering piling your leaves onto the soil surface to protect the soil from heavy winter rains. You’ll have a better soil structure in spring (you can rake the leaves off if you need a seed bed) and fewer weed problems too.

Making leaf mould is easy. All you have to do is to collect wet leaves (from deciduous trees) into one place and leave them to rot down. You can make a leaf mold bin with 4 stakes and some wire mesh, or you can just put leaves into a plastic bag. The container doesn’t matter, as long as it either lets in rain or you use wet leaves. You’ll also need a few air holes – if you’re using plastic bags then trying stabbing them with a garden fork a couple of times.

All you need then is patience. Some leaves take longer to break down than others, but after a year you’ll have partially rotted leaves that make good mulch material. If you want properly composted leaves you’ll have to wait at least another year – but once you start making leaf mold each year you’ll soon have an annual supply.

Want to know more? Listen to episode 32 of the Alternative Kitchen Garden Show.

Posted in Blog on Oct 11, 2013 ·

Tag: compost

The Composting Obsession

View comments (4)

Compost heap
A composter’s dream heap

We’re coming to the end of International Compost Awareness Week, an annual event designed to promote composting on all scales, due to the important environmental benefits it brings. Removing biodegradable waste from landfill, and returning it to the soil, solves pollution problems and increases soil fertility in one fell swoop. As a newly reinstated Master Composter (now that I’m home from university), I am fully qualified to tell you about the benefits of composting ;)

But what the press releases won’t tell you is that making your own compost can become a bit of an obsession. The problem, for a gardener, is that you just can’t get enough of the stuff. There are pots to fill, and plants to feed, and although you’ve got the space for another heap, you’re just not sure how you’re going to fill it….

You’ve rifled through the bins and removed anything remotely compostable. You’ve begged your neighbours to give you their lawn clippings, and even their used tea bags. You drive out of your way to visit that coffee shop that will happily load you up with their waste coffee grounds, and you’re travelling around with a bucket and spade in the boot in case you happen on an untended pile of horse manure.

And now you’re eyeing up any other potential sources of organic matter with which you can feed your heap. You know all about the importance of balancing our your ‘greens’ and ‘browns’, and have been keeping your cardboard to one side to add to the heap as necessary. So I don’t need to warn you about that, but there are other potential hazards you need to bear in mind as you wander the streets in search of fuel for the compost bins:

  • Firstly, you should never remove material from wild spaces. It might look out-of-control, and as though you’re doing the environment a favour, but other beings live there and you’re disturbing their home. Humans produce plenty of waste products, so look for those instead.

  • Avoid material that is likely to be contaminated – those piles of autumn leaves by the roadside may look appealing (you have plans for a special leaf mould bin) but they are likely to be polluted and won’t add anything good to your garden.

  • Anything spiny can cause problems – the prickles seem to take much longer to rot down than anything else, making it hazardous to handle your compost without thick gloves.

  • Plant material from unknown sources could be diseased, or contaminated with herbicides.

  • Perennial weeds, and seeding weeds, are only killed by very hot heaps. If in doubt, leave them out, or at least compost them separately and for a very long time.

  • Cooked food, meat and dairy attract vermin. If you really, really, want to compost them yourself instead of sending them off in your municipal food waste collection, then invest in a pair of Bokashi bins to treat the waste before you compost it.

  • Pet waste from carnivorous animals (e.g. cats and dogs) is another no-no unless you can provide a separate system (a wormery can work) and keep the finished compost separate and away from your food crops.

So, those caveats aside, what else can you use to feed your soil and compost heaps? I have collected litter from pet bunnies (who lived on a houseboat, no less) that consisted of sawdust and bunny poo. I’ve investigated collecting hop waste from local breweries (another reason to celebrate the return of microbreweries!). And when I worked I brought home the coffee grounds from the coffee machines in the office, although that got me funny looks.

Gardeners tend to jealously guard sources of organic matter once they have found them, but have you got any generalised tips you can share with avid composters?

Posted in Blog on May 10, 2013 ·

Last modified on Nov 20, 2014

Tag: compost

Biochar compost is as good as gold

View comments (1)

Earlier in the month I received a press release from Carbon Gold, whose biochar compost products have been through the first commercial trials in the UK with professional horticulturalists. Apparently, biochar “helps to boost root growth, reduces the need to water, improves germination rates and results in stronger, healthier plants which are more resilient to disease and changing weather conditions” (you can read more in the trial highlights PDF available from the Carbon Gold website; a more detailed report on the trials will be available at the end of the month).

Carbon Gold is a UK-based company, producing peat-free biochar growing products that are approved by the Soil Association. It’s great news that their composts perform well, but to me it’s more interesting that in the trial they performed as well as, or better than, peat-based composts. Comments from the trialists included:

“Excellent peat substitute, better than green waste. Would not hesitate to use as part of a John Innes mix.”
Fergus Garrett, Head Gardener & CEO of Great Dixter

“Switching from our usual compost brand to Carbon Gold has cut water usage by a third. The GroChar compost is less prone to drying out.
Jez Taylor, Market Gardener at Daylesford Organic Farm

“Despite a rather sketchy year, due to the weather and erratic temperatures, I’ve seen excellent root growth in the seedlings I’ve grown with Carbon Gold Soil Improver, I’ve had to water less and it also works well in my own compost mix.”
Mark Diacono, author, smallholder and garden designer at Otter Farm

Although biochar works well in the Amazon (where it’s known as Terra preta and is a traditional soil management technique), we need more trials examining whether it has a role to play elsewhere – there are too many variables involved in environmental problems to assume we can find a one-size-fits-all solution.

In the meantime, it’s good to know that there’s some more high quality, peat-free products on the market for gardeners, so that we can leave peat where it belongs, in the ground.

If you’re pondering the change to peat-free gardening, then have a look at The Peat-Free Diet, my latest book. It’s available to read free here on the website, or to purchase as an audio book.

Posted in Blog on Nov 20, 2012 ·

Tags: peat-free & compost.

Zombie Plants

View comments (3)

This blog post has been very kindly sponsored by Linda from Linda’s gardening journey. It’s not commercial content – click for more information on my sponsored blog post policy.

Zombie Plant - by Phil Jones

Zombie Plant – by Phil Jones

Happy Halloween!

I recently read an entertaining blog post on Claire’s Crops about the easiest way to get plants to self-seed in your garden that gave me the idea for this blog post. So today, in honour of the year’s creepiest day, I bring you Zombie Plants – plants that rise from the dead.

Not literally, of course. I can’t give you a spell that will resurrect that house plant you forgot to water for 6 months and which your Auntie Mavis gave you and will expect to see alive and kicking in a prominent place when she next comes to visit. You’re on your own there.

When I decide a plant is dead, and give up on it, it goes on the compost heap. The plant may not have the same idea. I had a lovely fern once, which I planted out in the garden. It promptly died, as my garden is pretty sunny and dry and it didn’t like the conditions. After a suitable mourning period (I love ferns) I tossed it onto the compost heap. When I next emptied the compost heap, the fern was alive and kicking. A little pale from lack of sunshine, but then you’d expect that from a zombie plant. I planted it out in a shadier spot and… it died. Sadly the magic of the compost heap was not enough to resurrect it a second time.

One of the creepy things that happens quite often with wormeries is that potatoes start to grow in them. The first you know is when those giant, white and fleshy tendrils start poking out all over. There’s a triffid in there, growing from a tiny scrap of potato peeling that had an eye on it. It’s tempting to hack at the thing with a machete until it dies, but there’s no need – it will run out of energy and decompose in due course.

As Claire mentions in her blog post, plenty of plants come back from the dead by distributing their seeds in the compost heap. Some of them are weeds, and that’s unfortunate. But unless you have a hot heap you can use your compost heap as a way to distribute self-seeding plants in the garden. It’s what happened with opium poppies in mine – I tried sowing them the recommended way, by scattering the seed myself, and it didn’t work. When I nurtured seeds inside I managed one or two plants; it was their composted seeds that helped to bring an army of zombie poppies into my garden. Other zombie armies that have arisen include parsley (in paving cracks!), Welsh onions and tree spinach.

The middle of winter can be a pretty desolate time in the garden, unless you’ve been super-organised and planted a lot of winter crops. Frosted, bare soil and stark branches make everything look dead. But, come spring, lots of things will be rising from the dead. Again, some are weeds, but the more impressive growth comes from tubers that have survived the winter underground. These zombies send out shoot towards the light, all the while decomposing as they sacrifice themselves to new growth. Volunteer potatoes, Jerusalem artichokes and Chinese artichokes can all rise from their wintry graves with no warning. Garlic is also great at this, as you can plant cloves in late autumn and see nothing poking above ground until early spring.

What rises from the dead in your garden?

You can find more spooky goings-on in The Zombie Garden.

Posted in Blog on Oct 31, 2012 ·

Last modified on Aug 10, 2015

Tag: compost

Unless stated, © copyright Emma Cooper, 2005-2014.