Widgets Blog - Emma the Gardener

Growing plants in lunar soil

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Apollo 15: Irwin Scoops up Soil

Astronaut James B. Irwin scoops up lunar soil during Apollo 15, 2nd August 1971.
Image: NASA

When Neil Armstrong made his giant leap for humankind in 45 years ago, he got covered in Moon dust. Throughout the Apollo missions, dust was an issue. Fine but rough, it caused problems with the space suits, and created mini dust storms in the cabin once the landers launched back into space.

On Earth, mineral soils are formed from the underlying rock by weathering, which is a collection of natural processes that gradually break down the rock. Weathering can be mechanical (through atmospheric conditions such as heat, water, ice and pressure) or chemical (when the surface rock reacts with water, oxygen or chemicals produced by plants). The rock particles then combine with organic matter to form what we know as soil.

On the Moon, that doesn’t happen. Lunar dust is formed from lunar rock (regolith) when small meteorites hit the Moon’s surface and pulverize the rock. Some of the rock melts and then cools, coating the dust with a glassy shell. There’s no organic matter for the dust to combine with. UV rays by day, and solar winds by night, create charged particles and give lunar dust ‘static cling’. Oh, and tiny specks of iron make it magnetic. So it’s not your run-of-the-mill Earth soil.

But would anything grow in it? The short answer is no – the minerals it contains are locked up in a form that plants can’t access. Whilst it might be possible to use Moon rock as a ‘substrate’ for hydroponic growing (essentially there merely to hold the plants up), all of their nutrients would have to be supplied with a fertilizer.

But that’s not the final word on the subject. NASA did some plant experiments with Moon rock at the time of the Apollo missions (mainly as part of their quarantine procedures to make sure they hadn’t imported health risks with their souvenirs). They didn’t attempt to grow plants in lunar soil, but they exposed plants to it. Not only did they find no negative effects, the experiments seemed to show that the plants benefited from the Moon dirt – results that have not been replicated. Since then the Moon samples have been considered a precious commodity and have not been made available for destructive research such as grinding them up to grow plants. So researchers have to use ‘simulants’ – Earth rocks that are similar in type to those found on the Moon.

Early in the new millennium, a team of researchers led by Natasha Kozyrovska and Iryna Zaetz from the National Academy of Sciences in Kiev, conducted a series of experiments with French marigolds (Tagetes patula) in one such simulant – anorthosite. They published their results in 2006.

Unsurprisingly, seeds sown in plain old crushed anorthosite didn’t grow into plants. But they were the control group. A second set of seeds was inoculated with a microbiome (bacteria and fungi known to promote healthy growth), whilst the crushed rock was also seeded with bacteria – and in this more complex ecosystem the seeds were able to germinate and grow into flowering plants. The microorganisms present were helping the plants to extract nutrients from the rock, and the authors suggested that this might be a way of starting to grow plants on the Moon.

Reading through the paper, I got the impression that what the authors were proposing was a kind of space permaculture. Lunar regolith is sterile, which not only means that plants can’t rely on microorganisms to release nutrients, but also means that any soil made from them would be a blank canvas for microbes accidentally brought from Earth. Rather than fungi and bacteria that promote healthy growth, you could end up with an imbalance – an environment that is harmful to plant growth. The idea of inoculating the seeds and the regolith was to promote a healthy soil environment that could protect plants against pests and diseases.

French marigold

The selection of French marigolds was not random. The scientists wanted to grow ‘pioneer’ plants that would not to be too fussy to grow in the nutrient-deprived lunar soil. These ‘first generation’ plants would then be composted to create organic matter and real soil, but the goal was also for them to be multipurpose. They were looking for plants to recycle waste products and produce oxygen, which had potential nutritional and medicinal benefits, and that flowered and so could improve the psychological well-being of the astronauts. Providing all these benefits, whilst kick-starting a sustainable ecosystem that makes use of local resources, is a tall order – but apparently French marigolds fit the bill!

The paper mentions another problem with growing plants on the Moon – the Sun is up for about two weeks, and then down again for the same period of time. If you don’t want to go to the expense of supplementary lighting, it reasons, the only solution is to chill your plants so that they are dormant until the Sun comes out again. In the meantime, I guess those long nights are perfect for forcing vegetables and sprouting seeds! Or perhaps mushroom cultivation….

And so it’s time, once again, for you to choose the next leg of our space blog adventure! Would you like to know more about growing fungi in space, how scientists choose which crop plants will be grown in space, or the Moon trees (grown from seeds taken into orbit around the Moon during Apollo 14)? Cast your vote below, or if you have a suggestion for a different topic, leave a note in the comments :)

And you’ve chosen…

how to choose space veggies


NASA’s Dirty Secret: Moon dust

Kozyrovska, N. O., Lutvynenko, T. L., Korniichuk, O. S., Kovalchuk, M. V., Voznyuk, T. M., Kononuchenko, O., … & Kordyum, V. A. (2006). Growing pioneer plants for a lunar base. Advances in Space Research, 37(1), 93-99.

Gardening on the Moon

Posted in Blog on Aug 2, 2014 ·

Last modified on Aug 17, 2014

Tags: science & space.

Changing landscape

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Didcot A

At 5 am this morning, the local landscape changed considerably. Scheduled in the early morning for “healthy and safety” reasons, controlled explosions demolished three of the cooling towers of Didcot A, a coal-fired power station that closed in March last year. There are three more cooling towers, due to be demolished next year.

The demolitions gathered a lot of public interest, and despite the early hour many people took to local vantage points to see them come down. Although some may have considered them to be blots on the landscape, the Didcot cooling towers have been a landmark since the 1960s. Visible for miles around, for many people they signposted the way home, and were a welcome sight at the end of a long journey. They were that for me when I lived in Abingdon; even more so since I moved to Didcot last year.

For several months now I have seen them every day, on my drive into work. It will be strange to see half of them missing on Monday, but I won’t be driving that way on a regular basis for much longer – we’re hoping that we’ll have a moving date very soon now.

The timing of the demolition was unpopular, with many people asking to change it to a more sociable hour, but Didcot A power station is no stranger to controversy. Its reliance on coal fuel made it environmentally polluting (it was targeted by eco warriors) and left it with the problem of disposal of the waste ash. The cheapest and easiest solution for RWE nPower was to pipe the ash into local gravel pits, but in the intervening time the gravel pits they had been holding on to for future use filled with water and became Radley Lakes – a local wildlife haven and green space amenity. When the time came to destroy them, the Save Radley lakes Campaign fought long and hard to protect them. They won out in the end, but more due to economic considerations than environmental ones. The Earth Trust now manages Thrupp Lake as a wetland site, and is planning to build a visitor centre.

Once the remaining three towers are removed, Didcot will be left with a brownfield site. I’m not aware of any current plans for its redevelopment – but according to the Oxford Mail, the ground is likely to be too contaminated to be reused for housing. It’s not the kind of place where you would want to plant a kitchen garden, that’s for sure, but a new day has dawned for Didcot and we will have to wait to see what it brings.

Posted in Blog on Jul 27, 2014 ·

Tag: environment

Moose dribble v toxic fungus

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munchin' moose

Photo credit: Steve Wall

In my occasional series, “When Plants Attack” we’ve seen some of the ways in which plants can defend themselves. So far I’ve covered the chemicals they produce to discourage other plants from growing in their space (allelopathy) and the conventional weaponry they use to guard against a physical attack. I am planning more posts to continue the series, which will include a look at the chemical defences plants have evolved to protect themselves against being eaten. But as soon as a plant evolves a defence mechanism, predators will begin to evolve or develop a way to counteract it. For example, some insects can collect poisons from the plants they’re munching on, and use them as part of their own defences. But until now it has seemed as though plant-eating mammals change their behaviour to cope with toxic plants – e.g. by changing how they forage for food, or by eating dirt (geophagy) to detox.

On Wednesday a paper published in Biology Letters put forward what the authors believe is the first evidence of large mammals evolving to combat a plant’s chemical defences. The researchers collected saliva samples from moose (Alces alces) and European reindeer (Rangifer tarandus) in Canadian zoos, whilst the animals were anesthetized to undergo necessary medical procedures. These two animals are known to feed on red fescue (Festuca rubra), a grass which occurs around the world. Red fescue uses a common defensive strategy: it forms a mutually-beneficial relationship with a fungus (Epichloë festucae), which produces toxic alkaloids.

By applying the animal saliva to grass samples, the researchers demonstrated that both moose and reindeer saliva slowed down the growth of the fungus, and so reduced the amount of toxin that was produced. Moose dribble also appeared to directly affect the levels of the toxin in European samples of the grass (the deployment of chemical defences depends on the environment in which the plant is grown), and the scientists theorize that the saliva is preventing the plant’s defence system from activating, by disrupting its signals.

So it seems that moose and reindeer aren’t just coping with the toxins produced by their diet of red fescue, but have evolved to actively combat them. “Plants have evolved defense mechanisms to protect themselves, such as thorns, bitter-tasting berries, and in the case of certain types of grass, by harbouring toxic fungus deep within them that can be dangerous or even fatal for grazing animals,” says York University’s Professor Dawn Bazely, who worked with University of Cambridge researcher Andrew Tanentzap and York University researcher Mark Vicari on the project. “We wanted to find out how moose were able to eat such large quantities of this grass without negative effects.” This interesting discovery (which will have to be verified by further studies) may seem a little esoteric, but you never know when you might need an enzyme that deactivates a toxic alkaloid (and this particular one also appears in ergot), and when you do it’s good to know that moose happen to have one handy.

You may also be fascinated to learn, as I did during the course of my research for this blog post, that whilst the common usage of “ungulates” refers to hoofed mammals (such as moose, reindeer, cattle and camels), cetaceans (whales, dolphins and porpoises) are also ungulates, sharing a common ancestor with the other species in this large group of mammals.

Tanentzap AJ, Vicari M, Bazely DR. 2014 Ungulate saliva inhibits a grass–endophyte mutualism. Biol. Lett. 10:20140460.

Posted in Blog on Jul 26, 2014 ·

Last modified on Aug 25, 2014

Tags: science & fungi.

Bees in space

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footprint on the Moon

Image credit: the NASA History Office and the NASA JSC Media Services Center

Today marks the 45th anniversary of the Apollo Moon landing, which seems like a good time to take the next step on our space adventure. You choose the topic of bees in space, so here we go!

In 1984, 3400 honey bees (Apis mellifera) joined the crew of the Challenger space shuttle for a mission in space, housed in an aluminium “bee enclosure module” (BEM) as part of a student experiment to so see whether they could build honeycombs in microgravity. Weightlessness didn’t seem to bother the worker bees too much, and they produced a perfect 30 sq. in. comb. The queen laid 35 eggs, but they didn’t hatch. As honeybees won’t foul their nests, and the enclosure was sealed, the bees had to ‘hold it in’ for the duration of the 6-day mission, and were probably glad to return to Earth!

In 2003, the first ever space experiment from Lichtenstein, dubbed “Spice Bees” by its student designers, launched 3 Carpenter bees (probably Xylocopa c. arizonensis) into orbit on space shuttle Columbia. They were housed in a special balsa wood habitat, and deemed to be more active in microgravity than earth. The students were waiting to weigh the balsa block when it returned to Earth, to see how much wood the bees had eaten during 15 days in space. Sadly the bees perished, along with their fellow astronauts, as Columbia burned up on reentry.

In 2012, scientists at the University of Guelph in Ontario performed a series of experiments on Earth to test whether bumblebees (Bombus impatiens) remain effective pollinators at low atmospheric pressures. NASA and other space agencies currently recommend a pressure of 52 kPa for sealed greenhouse environments (for Mars or the Moon), which is cheaper to maintain than the 101 kPa found at sea level on Earth. Experimental results show that plants will grow well at 52 kPa, and bumblees will pollinate them. In contrast, honeybees can’t fly below about 66.5 kPa, and don’t react well to enclosed environments, making bumblebees a better bet for extraterrestrial pollination.

And that’s the history of bees in space. For our next adventure together, I suggest a trip to the Moon. Investigating the possibility of creating a lunar seed bank was a popular second choice in the last vote, so we’ll give that another chance. We could also learn more about the soil on the Moon (regolith), or delve into the history of the Moon trees, which were grown on Earth from seeds that orbited the Moon in Apollo 14. It’s time to choose your own adventure – which way is the solar wind blowing us?

The votes are in!

Lunar soil wins the poll

Burgess, C., & Dubbs, C. (2007). Animals in Space. Praxis Publishing Limited, Chichester, UK.

Chien, P. (2006). Columbia: Final Voyage. Springer.

Nardone, E., Kevan, P. G., Stasiak, M., & Dixon, M. (2012). Atmospheric pressure requirements of bumblebees (Bombus impatiens) as pollinators of Lunar or Martian greenhouse grown food. Gravitational and Space Research, 26(2).

Wikipedia’s list of space shuttle missions

Posted in Blog on Jul 20, 2014 ·

Last modified on Jul 29, 2014

Tag: space

Grinning, winning cress heads

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Day 203/365 : 12.7.13

Photo by kennysarmy

If you’re looking for ways to keep the little ones occupied in the summer holidays, then check out this competition from Chiltern Seeds. Call 01491 824675 or email to request a free “CRESS HEAD PACK”, and they’ll send you a packet of cress seeds, some googly eyes and some coloured pompoms to make your very own Cress Head/Animal/Alien/Loch Cress Monster (I’d love to see a Loch Cress Monster :)

It’s then up to you to decide how to style your cress head, but once you’ve sown your seeds and waited a few days for nature to take its course, then snap a few photos and email them to Chiltern Seeds – the most imaginative cress head will receive a £40.00 book token.

Growing cress is easy, but if you haven’t tried it before, then have a look at my blog post on how to grow mustard and cress for the low down. There’s also a guest post with some other plants little ones love to grow. Happy sowing!

Posted in Blog on Jul 19, 2014 ·

Tag: seeds

Summer garden activities

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Garden Arbor

The house I grew up in had a very large patio. In the summer we had a paddling pool that my parents could set up, that these days would be classed as a swimming pool. It was made from sturdy canvas and poles, and had a plastic seat on each corner. It took quite some time to fill from the hose, and was – of course – completely freezing to begin with. Once the sun had warmed the water up a bit, we had fun splashing around. The pool didn’t have a cover, and my parents never thought to improvise one, so over the next few days the surface of the water would become littered with flies. When it became too disgusting to swim in, we let the water out. The British summer being what it is, it was rarely worth refilling at the weather had usually cooled down by that point. We also used to have the occasional meal outside, on a patio table with an umbrella, but this wasn’t my favourite activity due to the wasps it attracted.

My old garden would have been large enough to house a small, temporary pool in the summer, and it’s one thing I would dearly love when it’s very hot. But the new garden isn’t big enough. We have been looking at sheds and greenhouses, trying to fit in everything we want without losing too much of my gardening space. The final design will have to wait until we’ve moved in, and can measure up properly.

I’m hoping to find space for my arbor, so we have somewhere nice to sit. Ryan would like a good BBQ. Fortunately these days there’s a much better range of insect repellents and was traps that can help to keep outdoor dining pest free, but once I’ve had time to do some planting the garden should be chock full of aromatic plants to confuse bothersome insects and keep them busy elsewhere! Some sort of water feature would make any traffic noise less obvious, and make our little garden a relaxing haven for a nice glass of Pimms or wine on a summer evening, making winding down after a day at work a doddle. For those ‘summer’ days that don’t quite make the grade, it would be nice to have a patio heater of some kind; Calor Gas have some very stylish options on offer.

In the cooler hours of the day I will enjoy watering my plants and pottering about in the garden. And, of course, there’s also the joy of picking (and, usually, munching) anything tasty that happens to be ripe as you wander past. I’m particularly looking forward to alpine strawberries, courgettes (although Ryan is not yet convinced he likes them), leafy greens and peppers from the greenhouse.

So… my ideal summer gardening activities would be eating and drinking, relaxing and pottering about. What are yours?

Posted in Blog on Jul 18, 2014 ·

Tag: general

Gum arabic under the microscope

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In this video from the University of Cambridge, Rox Middleton shows us a ‘nanoscale’ image of gum arabic, taken with an electron microscope. Gum arabic is the hardened sap of an Acacia tree; this sample was probably collected in Sudan. If you want to see what it looks like on the everyday scale, I took a photo of a chunk when I visited the Oxford University herbarium. Gum arabic is a food additive, E414, used as a stabiliser. It’s also used in paints and pigments.

Posted in Blog on Jul 16, 2014 ·

Last modified on Jul 9, 2014

Tag: science


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SEM mint image

This isn’t a fantasy alien landscape, its an image of a mint leaf, taken with a scanning electron microscope by Annie Cavanagh. This low-res version is available from Wellcome Images with a Creative Commons license, which allows me to show you how awesome plants are. The spike is a trichome (a hair, essentially). The blobs are oil, sitting on oil glands, and are what gives mint is delicious flavour. The oval structures that look a bit like seeds scattered on the surface, are stomata, the holes that the plant can open and close to regulate its intake of carbon dioxide and the expulsion of oxygen. You can just see the slits along the centre, which is where they would open up.

Posted in Blog on Jul 12, 2014 ·

Tags: science & herbs.

Book classification system

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We still don’t have a date for moving into the house, and nothing is certain, but I am looking forward to the day when I can be reunited with my books. For two years now, many of them have been stored in my parents’ garage; some travelled with me to Kent and although I briefly lived in the same place as some of them, they’re now in a storage locker.

Although I have missed some of my fiction favourites, it’s the distance from my reference library that has pained me the most. Now that it appears the end of the separation is in sight, I have been giving some thought so how I will organise them in their new home.

I used to have an ad hoc system whereby books on a similar topic were clumped together, although it was complicated by the fact that I liked to keep books by one author together as well. I found it hard to keep track of which books I had, and where they were. When I was looking for a book on a shelf it was mostly by the memory of what it looked like – and, when I finally found one, it wasn’t unusual to find out that it looked nothing like I thought.

Keeping track of books in multiple locations has been trickier still. There are a few volumes that have slipped through the net, and are currently… somewhere, but I kept a list of the contents of each box I packed, and stored it in an Evernote database. Over the last few months this has morphed into a Library notebook, in which each book has a record based on a template. It lists the title, author, source details and current location. For non-fiction books it has a space for notes, and for a citation if I think I will want to make use of my research. New books are added as I acquire them, and as long as I keep the locations updated, everything is hunky dory. It’s nice to be able to refer to the database and know that, yes, I do have a copy of that book somewhere. (And it can keep track of ebooks in different formats, which I otherwise tend to forget I have.)

But unless I label my shelves with very specific location data, my Evernote catalogue isn’t going to help me find the book on the shelf. So over the weekend I decided to become a complete and utter library nerd and develop a personal classification system, so that I could label my books and shelve them in a way that makes some sort of sense.

I’m reasonably familiar with the Dewey Decimal System (DDS) from a user’s perspective, since it’s quite popular in libraries. The basic idea is that it is a ‘tree’ system, with ten umbrella subject categories at the top, each one of which is broken down into ten divisions, each one of which has ten sections. You end up with a classification for a book that looks like “629.786 FRE”, which includes the first three letters of the author’s surname, and means you can shelve books alphabetically within each section.

The problem with the standard DDS for me is that a) I wouldn’t use a lot of the classes, and b) I own so many different kinds of gardening/plant books that I keep running out of sections to put them in. So I looked at the topics of the books I do have, and tried to work out my own, personal classification system. I won’t really know whether it works or not until I have tried to shelve all my books, but I reckon they should all be covered by this:

Class 000: Plants and gardening

000 General gardening
000 General gardening
001 Horticulture
002 Wildlife gardening
003 Composting and soil
004 Permaculture
005 Community gardening
006 Weeds
007 Plant diseases
008 Garden pests
009 Garden history

010 Edible gardening
010 Edible gardening
011 Fruit
012 Vegetables
013 Herbs
014 Unusual crops
015 Edible flowers
016 Perennials and forest gardening
017 Foraging
018 Heritage varieties
019 Wartime gardening

020 Ethnobotany and anthropology
020 Ethnobotany and anthropology
021 General ethnobotany/ anthropology
022 Plant use
023 Food culture
024 Drugs
025 Aphrodisiacs
026 Off-grid living

030 Botany and plant science
030 Botany/ plant science
031 General botany reference
032 Plant identification
033 Botanical Latin
034 Botanical history
035 Propagation

040 Fungi and microbes
040 General fungi
041 Fungi cultivation
042 Microbes

050 Garden animals
050 General animal reference
051 Chickens
052 Bees
053 Insects and minibeasts

Class 100: Food

100 General food
100 Food
101 Food memoir
102 Food history
103 Spices & seasonings
104 Tea and coffee
105 Other drinks
106 Seaweed and algae

110 Recipes
110 General recipe books
111 Garden to table
112 Asian
113 Middle Eastern
114 Spanish
115 Nordic
116 Baking
117 Vegetarian
118 Ices
119 Slow-cooking

Class 200: Science

200 General science
200 General science reference
201 Popular science
202 Chemistry
203 Physics
204 Space
205 Environment

Class 300: Humanities

300 General humanities

310 Writing
310 General writing
311 Freelance
312 Science
313 Home & garden writing
314 Publishing

320 Languages
320 Languages
321 Spanish

330 History
330 History

340 Crafts and hobbies
340 General crafts/ hobbies
341 Photography
342 Papermaking
343 Drawing and illustration
344 Travel

It clearly has plenty of room for expansion. You may be thinking that it’s overkill for a personal library. It might be – but I have over 300 titles in my non-fiction collection and, having had the experience of wanting to pick up a book I once read but no longer own, I am loathe to have any more clear outs. Plus, it may be nerdy, but putting it together made me happy :)

I should be able to use my Brother garden labeller to label my books – the labels don’t fade, they’re removable and don’t leave behind a sticky residue (I know from using them for pretty much everything for a few years!). They may have to go vertically on the spine, rather than conventionally horizontal, but I can live with that.

Even once you have a classification system, what number to give a particular book is a bit of a judgement call. I have a copy of The Complete Yurt Handbook, which stumped me for a little while. I nearly put it in with the food books, because it’s the details of Mongolian food culture in it that I really enjoy (I’m never likely to build my own yurt!). Having put it to one side for a little while though, I found some other titles it naturally falls with – hence the “Off-grid living” section. In some ways it doesn’t matter, as long as you can find the book, but I like the serendipity of going to look for a particular book in the library, and finding something even better close by on the shelf.

Ryan bought me a Personal Library Kit, so I can be a proper librarian – it has a date stamp, and sticky wallets you can put in the books to mark in the date books are returned, and removable cards so you can keep track of which books are on loan, and who has them. Not that I intend to lend my books to many people – that’s a very quick way to lose friends!

Anyway, labelling and shelving my books should be a fun rainy day project once we’ve moved into the house. How do you keep track of yours?

Posted in Blog on Jul 10, 2014 ·

Tag: books

Daisy trick

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In this video from Cambridge University, Dr Beverley Glover uses a Scanning Electron Micrograph to explain the ‘trick’ that makes daisy-family plants more attractive to pollinating insects.

Posted in Blog on Jul 9, 2014 ·

Last modified on Aug 2, 2014

Tags: flowers & science.

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