With the trauma of the recent storm behind us and any bad weather ahead of us already firmly blamed on the fact it is the school holidays because it always happens that way. The moment they go back in a couple of weeks the sun will be shining and it will be the best conditions we will have seen in a long time. The house has stood up to the conditions admirably and gives us such confidence going forward that it will be a safe home for our family well into the future. I can let out a sigh of relief and return to delving into the wonderful world of dirt. There isn’t much time left before I can get out there and get my hands dirty, so I’d better get a wriggle on, understanding how to use it well.
Last time we explored they way plants like to receive their food, cut up into teeny tiny portions of a molecular size. However, this is a far cry from the way we deliver it to them. We lob barrow loads of compost at the soil, bucketful’s of well-rotted manure and handfuls of fertiliser and clumsily mix it all in with a garden fork. Compared to the fine dining going on in the soil, our contribution is rather rustic and about as far from refined as could possibly be.
So, the question to be asked this time is how does it get from chunky to tiny? The common phrases we hear are it is broken down, nutrients are released into the soil and plants absorb them – as if by magic. Now we know about the absorbing bit, so what is involved with the breaking down and releasing? If we start by looking at the common things chucked into the garden to ‘enrich’ the soil, we can get an idea of what we are starting with.
Gardeners are strange folk. There aren’t many people that would delight in a trailer old of animal poop delivered to their door. But this stuff would be similar to receiving a trailer load of gold dust to the right person. But there are conditions. It must be the poop of a vegetarian animal that grazed upon lands not recently sprayed with a systemic herbicide – some of these things can pass right through! And it needs to be well rotted before adding it to the soil in the presence of plants. Fresh poop still makes a great delivery, but you have to wait before using it and the best way is to pop it in a covered pile far away from any source of complaint and wait until it is no longer recognisable as what it once was. Fresh poop can do more harm than good. Once it is ready it should smell it a woodland floor and be nice and crumbly.
This is also a great addition to the garden to introduce organic material. It can end up being a wonderful closed cycle in a well-run garden. The spent crops are gathered up and put on the compost pile, the breaking down and releasing happens and what was once plant is now plant food and on the way to becoming plant again.
These are made up of ‘natural’ ingredients but more often than not, processed in some way, like blood and bone comes in a powder not in chunks of dead cow, rock dust is mined so it is a fine powder. Fish emulsion doesn’t come with visible bits of fish. It is to make it convenient for the gardener and also speeds up the process of making the nutrients accessible to plants.
These are purely man made to meet specific needs of the plant. The nutrients are often non-plant based and sourced from mineral deposits and processed in a factory. Sometimes seen as the bad guys in terms of delivering a healthy diet to the plant. But the advantages are they can be pretty specific with the contents analysis, where the more natural products are down to the vagaries of what the animal ate or the quality of the soil the now rotted plant grew in. These guys are often slandered as the fast food of plant world and not substantial enough for sustained growth. But as we learnt previously – the plants don’t even notice where it came from as they absorb molecules far removed from how they started out and a magnesium molecule recycled though a chicken could be taken into the root hair immediately after one from a packet! The plant isn’t fussy.
So, we now know what the food is predominately made up of, but how does it get small. How is it broken down? Well there is a fabulous process called mineralisation. This is just a fancy way to say decomposition, but if you look at both words de-composite is undoing structure and mineralisation is making something into minerals. But not wanting to over simplify things it is a complex process using a wide variety of soil creatures from the micro organisms that get to work once something dies, and start to break down tissue for their own needs, to the earthworms, bugs, beetles and other creatures that love to eat dead things. In doing so the dead material gets broken up into smaller pieces so the bacteria and fungi can access a greater surface area.
It is like a medieval banquet where the room is filled with all sorts of people for the occasion. The king cherry picks the good stuff and the quality of the servings diminish depending on the status, right down to the dog running off with a bare boar bone. At the end of the day there isn’t much left, however, the meal does reappear in a day or so in a different format and it doesn’t really matter if it came from a lavish throne or a humble origin it is one step closer to being mineralised.
This happens when the micro-organisms release enzymes that oxidise what is left from the ‘breakdown experience’ finally turning the chunky into tiny in a form plants can use. There are other factors at play here, like synthetic doesn’t need as much help from the micro organisms in the mineralisation process but gets there all the same. But there it is in a nutshell – it is all a bit of a giant feeding frenzy and a whole lot of poop broken down into every decreasing sizes.
So, adding loads of organic material and fertiliser should sort out my sandy soil…. Or does it?
Come again soon – we are almost at the point of knowing what makes my soil tick.
Sarah the Gardener : o)
A few weeks I asked this question in jest in response to the winter weather conditions. I now know exactly how bad it could be. We have just been through a terrible storm and it would seem it isn’t called the ‘wild west coast’ for nothing! Now I’m not naïve and I knew there would be strong winds, I just thought I’d have at least a couple more months to investigate the situation before winter conditions showed their hand. It is very important when moving to a new location to find out as much about, not only the soil, but the climatic conditions and that was next on my list.
But this week we have had a huge weather event, that seems to have even taken the boffins by surprise as there was little warning. Either that or it wasn’t a slow new week, so their warnings were drowned out by the noise from other worldly events. Somehow an Antarctic blast coming from the south became entangled in the lingering warmth of an exceptional late summer and got all excited. There was thunder and lightning and heavy rain – although at least it wasn’t floody. Most of the high places in the country were dusted with snow and for the rest of us, the temperatures plunged dramatically. But what did the most harm was the wind. My goodness it was wild. Three days later it is still making its presence felt, but on Tuesday night it can only be described as terrifying. Especially when you live in a caravan!
What makes it all the more terrifying is when your home-to-be is sitting up on thin metal jacks about 2 metres in air – facing the full brunt of the storm. The highest gusts were recorded about 30 km up the coast from us at Manukau heads with a whopping 213 km per hour. These were apparently only 10 km shy of the record for the highest winds we’ve ever had (well – since records began) So now we know – just how bad it can be.
The good news is, the house stood still and is a tribute to the Total Relocation Limited team. They have worked so hard and tirelessly on the job. But with our full support, work on the house has been put on hold until good weather returns. It is very frustrating for us, as we are so close to the end. But there are some things that just can’t be helped, and I would much rather have the team be safe and well than complain about our inconvenience. What‘s a few more weeks in the caravan really, in the grand scheme of things?
But what it has brought to light is the worse case scenario, before we even begin to create anything. This is a good thing. As all the farmer neighbours have said in all their years they haven’t seen anything like it, I think it is safe to use this as a benchmark for any of my projects to ensure they are built to last. I am rethinking the kind of greenhouse I will have as it clear an ‘off the shelf’ model just won’t do. This turn of events makes the greenhouse project even more exciting and I am really looking forward to exploring options that will keep my seedlings safe in the spring. But it isn’t just the greenhouse that needs careful consideration, the fruit cage, the orchard, even the washing line will need to be able to stand up to the conditions.
The general rule of thumb when moving to a new place is to wait a year before doing something in the garden to see what it is really like and to see what surprises pop up. The surprises normally refer to the possibility of a magnificent display of spring bulbs, and not intending to mean devastating winds. But I’m impatient and am glad I know now. I am also extremely glad no real harm came to our home, our family and our team during such a terrible storm.
Come again soon – things will improve soon enough.
Sarah the Gardener : o)
When you think about human health, what we need to keep us going seems simple in some respects: carbohydrates, proteins, fats, water, vitamins, and minerals. But these can come from varied sources and our diets are a wonderful combination of so many things, so we get what we need. I remember from my school days being taught that if all else fails, a boiled egg with wholemeal toast and a glass of orange juice would give you something of everything you need to start the day. It was one of the few things from that class that stuck.
But if you break it all down – carbohydrates are carbons, hydrogens and oxygens; minerals are naturally occurring chemical compounds like phosphorus, potassium, sulphur and magnesium. So, while a grand buffet at a fancy restaurant may seem like a great way to satisfy all our needs – we aren’t that different from plants and what we actually need is food that is on a molecular level, so our cells can utilise it best. But the beauty of it all is we can eat a wide variety of delicious things, so we can satisfy our tastes as well as our needs.
Plants on the other hand aren’t so lucky and need just a few things on a molecular level. The plants that give us wonderful things to eat are stuck with a very bland diet for themselves. Plants only need a handful of ingredients from the soil.
The ones that get talked about the most are the NPK combo. Nitrogen, Phosphorus and Potassium (we mentioned him earlier in the sciency stuff – he’s the K, just to confuse the already bewildered) These are the ones that get headline billing on bags of fertiliser, in the hope that the keen gardener will be able to work out which product is best for the plant. But then you need to know what your plant needs and what state your soil is in before making an informed choice, otherwise you are just taking a stab in the dark and could be wasting your money and stuffing up your soil. Over fertilisation can be a bigger problem than under fertilisation. This is why we need to know about these things.
Nitrogen (N) generally originates from organic material and is what makes strong shoots and leaves and makes healthy foliage. Although, depending on what you are growing, too much can come at the expense of flowers and fruit.
Phosphorus (P) is mineral from inorganic sources and helps the plant grow strong roots and we have already learnt the importance of strong, healthy roots.
Potassium (K) is also a mineral and plays a big part in plant reproduction – flowers, fruits and seeds. You really don’t want to lack this in the veggie garden or the harvest wouldn’t be all that great.
There are three other important ones that make up a huge part of the plant, Carbon (C), Hydrogen (H) and Oxygen (O) but the plant has no trouble getting hold of these, usually from the atmosphere to use in photosynthesis, that they are hardly even counted as the essential nutrients for plants.
But the plant diet is a little more varied than just these top six. There are others. The secondary elements, the plant needs them, but not in great quantities. However, they are essential for plant function and if they are lacking – for whatever reason, remember it doesn’t necessarily need to be absent from the soil, but just being too cold, or some other excuse, for the plant to take it up, the plant has ways of letting the gardener know. Nutrient deficiencies show up in the leaves like some kind of code – from yellowing leaves with green veins, to purple leaves, to patchy leaves to stunted and munted leaves. Each deficiency represents in different ways. It is a bit like a pregnant woman screaming out “I want ice cream and I want it now!” And if you know what is best, you go and find ice cream straight away!
So, these secondary elements are Calcium (Ca) and this is important for making strong cell walls. Sulphur (S) is involved in making chlorophyll, the thing that makes plants green, so it is kind of important as most plants are green! Magnesium (Mg) has an important job in the photosynthesis process so you really wouldn’t want your plant not to have access to this. But of an interesting note too much chicken manure in your soil can interfere with the availability on Magnesium. Which is another reason it is important to know all of this stuff. It is so easy to take handfuls of ‘good for the soil’ things and lob them about like it is some kind of lolly scramble, without realising you aren’t actually helping.
Then there are the Trace Elements. Plants need them but in minute quantities. The plant will let you know in its leaves if they are lacking, but absolute care must be taken when adding them to soil. You can’t unmake the sea salty.
Boron (B) has a key role in plant growth, so it is pretty important. Without it you can end up with stunted growth. Iron (Fe) and Manganese (Mn), like Sulphur are gainfully employed in the production of chlorophyll. Copper (Cu) and Zinc (Zn) work closely with enzymes to make things happen. Molybdenum (Mo) is a little-known nutrient that helps the plant convert nitrogen into more plant friendly forms and so the smallest nutrient is essential for the use of the largest.
There are a few other teeny tiny ones that are hardly worth mentioning and from what I can understand aren’t all that problematic or they would be higher up the list.
So if you look at it like a high school social structure – you have the popular kids, N, P and K – everyone knows about them and think they are important. They get talked about a lot! Then there are the kids everyone seems to like and get on with, but at the same time they are just average and ordinary and no one notices them. The poor C, H and O’s. Lost in their ease and abundance. The sporty ones – the secondary elements – they make the school look great – or not if they don’t do well and everyone notices them when they win or when they lose. The rest of the time no one really thinks about them, out there in the field, doing their thing and practicing all the time.
The trace elements have to be the geeks and the nerds. Their importance is barely noticed but without them there would be no school newsletters, no librarians, and no one to do all those volunteer jobs everyone else loves to hate. I have to confess back in the heady days of school I was a trace element and found there were certain privileges being in the science club that the more popular kids had completely overlooked – like being inside at lunchtime on a rainy day, for one! And ironically Nitrogen can’t be without Molybdenum doing its homework!
And that is what a plant needs in it’s daily diet to stay healthy. But we are still looking at things in a tiny molecular level and it is still a far cry from shovelling barrow loads of compost onto new season soil. So, the next question is, who chops up the plant food into bite sized chunks?
Come again soon – we’re almost there in this journey and then I can start digging.
Sarah the Gardener : o)
Over the last week we got a bit side tracked from the study of the soil, what with Easter and April Fools – I think my 24 carrot gold seeds were a bit too subtle… maybe I should have spray painted 24 carrots gold! Anyway…. The other exciting distraction over the last week is the house has arrived, but I’ll share more of that with you later, because I really need to press on with this soil science stuff. The arrival of the house has tightened the timeline, because as soon as they have finished sticking it all back together and council signs it off, then we can move in. That will mean the caravan and the container can go, and I can start my garden. So, I’d better know as much as I can about the soil before I get started. So where were we…
In order to understand my new sandy soil, I have been trying to understand how the plant works and how the soil works so I can make sense of it all and be a better gardener in less than ideal conditions. Last time was like the bit in a scary movie, where they are crossing a dangerous rope bridge and the hero wants to go fast to get across as quickly as they can, but needs to go slow and examine each tread so they don’t fall through. I feel like we have made it passed the horrible bits and are now safe of solid ground.
So, we know water is a great carrier of nutrients up into the plant, through the xylem, and the root cells have good systems for managing the nutrients once they get in. And we now know the nutrients need to be tiny – on a molecular level to get in. But the question remains: how do they get in? They don’t have arms and they’re not a sponge and don’t go about sucking up everything arbitrarily. It turns out the plant is very particular as to who and what it invites inside.
There are a couple of ways this happens down deep in the soil. One method is passive, and the other is active. The passive process occurs through a process called osmosis which is a kind of popularity contest for ions (the molecules with the electrical charge). Basically, they want to be at the exclusive party and all mill about outside the cell in high numbers, being absorbed through the semi-permeable cell wall into the cell where there are low numbers. The numbers are kept low as once inside the ions that are needed are escorted off into the heart of the root, across the cortex and beyond the casparian strip, and are locked into the plant and able to be used where needed.
However, the water is trying to control this movement and prefers things to be balanced on both sides so won’t let everyone in. If too many ions get in, it becomes too concentrated and the process reverses and the ions leave the cell like it is yesterday’s news. So, there can be a lot of coming and going in the root hair cell.
This is all very well if there are large concentrations of the ions needed lingering in the soil the roots are sitting in. But not all of the ions are there in large enough numbers to just drift in and have to be delivered into the cell like a VIP in an active system. The cool thing about plants is they have a process for everything they need and even create their own energy currency ATP (adenosine triphosphate for those who want to know). It is made in the respiration process up in the leaves.
Apparently, it is not known exactly how this works, but the cell walls of the root hairs have different carrier molecules embedded in them that recognise specific nutrients. Sort of like secret entrance ways and the energy from the ATP is used to bring in these nutrients against the concentration flow so the plant can get what it needs specifically.
I sort of see it like the DJ and the magician turn up to the party and is stuck in among all the party goers out the front. The party goers are having their tickets checked and allowed in so long as the party isn’t overcrowded on the inside. But the DJ and the magician are special and need priority treatment to get in and with the assistance of some currency to grease the wheels (ATP) they are whisked in through their own separate entrances.
However, this system has its limitations. If the temperature isn’t right and it is too cold or too hot, then the doors don’t open, so the DJ and the Musician have to wait outside for it to warm up. Meanwhile the party goes on without the talent. This can be seen in many common plant problems – if it is too cold phosphorus can’t get in and without it the plant turns purple. Or blossom end rot in tomatoes – it is due to a calcium deficiency and in most circumstances, it isn’t because it isn’t in the soil, but it is too cold to get into the plant and so the nasty rot problem occurs. This is why it is more common earlier in the season, when it is still a little cool and then comes right.
But even the passive system has something to teach us… if there aren’t enough nutrients in the soil, the ones already in the root hair cells have no choice but to leave, so they can hang out with their friends until the numbers become more concentrated that they can flow back in the other direction back into the cell. It would seem balance is the key to ensure the plant stays consistently well fed, not yo-yoing between feast and famine.
And that seems like enough to take on today. It would seem information uptake into my head is also limited by concentration levels.
Come again soon – I think we need to find out more about these all important nutrients.
Sarah the Gardener : o)
I am always up for a challenge and when I saw these fancy carrot seeds I just had to have them. They weren’t cheap, but I think it will be worth the investment in the long run. Germination can be a little tricky but so long as you don’t sow them too thickly it should be ok. I’ve used 24 seeds and I’m hoping for the very best!
This April is all set to be an awesome month, and we are starting it off with half a house and will end it with so much more.
Come again soon – there is so much going on, I’m not sure where to start.
Sarah the Gardener : o)
Currently, in my gardenless state, any opportunity to get up close and personal with any kind of gardening and I’m in. Even a rain soaked autumnal day won’t dampen my enthusiasm, so when I was invited to help pick apples and help get them pressed for cider making I jumped at the chance. I even dragged Hubby the Un-Gardener with me as being cooped up in a caravan on a rainy day is never ideal, especially after 64 days!
The weather had been good pretty much all week and was lovely since, but that day just happened to be the soggy one. I was worried they would cancel it, but they are like minded folk with a burning passion for making the most out of their land, exploring possibilities to as far as they will stretch. A spot of rain is not an issue. It was motivating to be with them and made me all the more eager to start my garden.
We drove down to the back of the farm past all manner of edible crops, fruit and nut trees, pigs and cows. If I was to have a farm like that, that would be the kind of farm I’d have. But I’m more of a plant person and managing plants is a lot easier than managing animals.
You could see the orchard from a distance as the greenery of the trees was dotted with the red of ripe Gala apples. As the orchard was at the far end of the farm, it reminded me so much of my old orchard at the far end of our old place. The grass was long, and the fruit wasn’t quite perfect, and I felt so much at home there.
The first task was to clear away all the fallen fruit, so it wouldn’t be confused with the fresh fruit that was soon to be shaken from the trees. All but the very rotten was picked up and put in buckets for the pigs. It was a good thing I’d bought along my Gardena fruit collecting tools as the Fruit Collector made short work of this job as the icky fruit slipped easily through the flexible wires. Hubby the Un-Gardener nabbed this tool and so I was left rummaging around on my hands and knees, picking up smooshed and the pecked fruit. I looked across enviously at Hubby the Un-Gardener who was clearing up under trees in a great rate of knots without so much as getting his fingers messy.
But it did speed things up, as the clouds above were heavy with rain and a new downpour was threatening to make things unpleasant. Once the ground was declared good to go the trees were given a good shake and the ripe fruit came crashing down. Once again Hubby the Un-Gardener leapt into action and quickly swept up the fallen fruit and the crates were filled fast. There was stubborn fruit that refused to fall and there was something satisfying, to reach up into the branches and pluck armfuls of apples, visibly clearing the tree of its crop.
As we stood back and admired our mornings work, the heavens opened, and the rain came down. There was nothing else for it but to load up all we had collected and return to the farmhouse for wonderful shared lunch. The homemade pea and ham soup seemed perfect for the day. Shamefully my contribution was not lovingly crafted by me, but by the good people in a food factory far far away. It is just too hard to do that sort of thing in the caravan. But just wait until I get my new kitchen – oh the things that will come out of there in the months and years to come!
The highlight of the lunch was to sample the cider, from the orchard, from the previous season. It was so light and refreshing, although I could feel a slight kick coming over me. Just as well we were rounded up to take the apples to the next level. The set up was a dream cider making operation, with everything hand made or put together by our friends. An old bathtub at a good height was filled with water and the apples were washed and scrubbed and any rot, coddling moth or particularly manky bits chopped out.
They were then put into the amazingly crafted handmade crusher. There was a therapeutic action to lifting the lid to add the apples, then allowing the weight of the lid to press them against the wooden drum studded with screwheads to turn them into pulp. A frequent addition of melted bees wax kept the drum lubricated as the small motor kept it all spinning.
From there the pulp went straight to the press, where it was stacked between boards in cheesecloth wrapped bundles, five high and gently squeezed with the aid of a car jack. The juice was encouraged to pour from the fruit and was the sweetest I’d every tried. Once squeezed dry, the flattened pancakes of fruit were put aside for the lucky pigs and the juice was taken away to begin the fermentation process.
It was such a lovely day and we look forward to the day we are invited back to sample the fruits of our labour. It also made me keen to begin to think about the trees I want in my new orchard. Soon it will be fruit tree planting time, so I should give it a little thought.
Come again soon – we’re still looking into this dirt thing as bite sized chunks make it so much easier to understand.
Sarah the Gardener : o)
I find if I want to figure out how something works it is important to know everything. I’m not very good at accepting things at face value if it means I’m not quite clear on how it works. Except possibly the remote control on the TV. That is way beyond me and I freely admit to asking the kids to switch it from X-box mode to my favourite TV channel so I can watch gardening shows (when they are on, they can be a bit few and far between on our screens – and also when we had a house… oh the good old days! But we’ll get a new one soon enough). When it is something I’m deeply passionate about, like the garden, then settling for a casual answer just isn’t enough. I need to know how and why, so I can be a better gardener with my new, vast quantity of sandy soil.
Sometimes this takes us to easy places, like the straight forward plant biology, but it can take us to the scary world of chemistry. Chemistry was never my strong point – it is like maths in disguise. But I need to push past school days trauma and dig about for the answer to “how does this absorb thing actually work?”
Deep breath…. Here we go…
Last time we discovered the intrepid root hair cells that get out amongst the soil, risking their fragile lives to hunt and gather the moisture and nutrients the plant needs. But it is all very well to say they absorb or gather, The thing is, they don’t ‘go about’. They are fixed, anchored – rooted to the spot. So they have their outreach as far as their root hairs will go. Generally they aren’t seeking anything out. They are more like the filter feeders of the ocean, like mussels and oysters, glued in position and hoping what they need comes by. They don’t go cracking open soil particles looking for what they need. And remembering the root hairs are microscopic single cells that take on the nutrients, then you need to consider the nutrients need to be really tiny, much smaller than the handfuls of fertiliser, compost, manure or other things you scatter about the soil between the growing season to enrich the soil. Things need to happen to that to make it accessible, but we’ll talk about how it goes from chunky to tiny another time. What we need to know now is about the tiny nutrients and how they get into the plant.
Technically nutrients are broken down into atoms and molecules. So going back to school chemistry – if you remember the periodic table – a colourful chart where most things have a short ID of who they are like C for carbon and N for Nitrogen, but others are just odd to confuse bewildered students like Au for Gold (what’s that all about? – it isn’t like G isn’t available or Go for that matter) and K for Potassium. Well this is a big list of all the chemicals in the world (which are atoms, and are the smallest form of chemical, from what I understand) that go together like Lego to make up everything in the world. It doesn’t matter if it is organic or not – everything in the world can be broken down to a collection of these individual things.
The atoms are joined with others in amazing combinations to become things. They are joined together with electric bonds. If you go back to the periodic table, each thing has a number which tells you how many …
Oh my goodness we have to go deeper – each atom has a nucleus, which is the main bit of it and in it are protons which are positive and neutrons which are neutral and then it has electrons, which are negative, around it – kind of like the planets around the sun. Now depending on how many of each the atom has ultimately determines if it is a negative atom or a positive one. Which determines who it can hangout with to become a molecule. (still sort of like the Lego block – still made of something but that ‘something’ (the plastic) if you broke that down it isn’t Lego anymore, but also looking at the Lego block – does it have two bumps or six?)
Did I mention I don’t like chemistry? – well I hope I’m not losing you as I’m in danger of losing myself here. But this is important because these atoms join together – electrically with their electron glue. I could go deeper into this but it is complicated. But essentially it is like a jigsaw – some fit together and some don’t. Plants need ones that are water soluble so they can easily join the flow of water through the plant via the xylem. If you think about it – the two hydrogens and the oxygen in water are like three kids dancing in a circle and then others come in and join them and the song changes, but there are some kids they don’t want to play with. But also there is a limit to how big the circle can be so even some of the ‘right’ kids miss out. Ie the water can become too saturated with the chemicals and limits the amount that stays in solution. So even on an atomic level you can have too much of a good thing, so over fertilizing is a wasted effort. The number of kids that can join in is also affected by pH and temperature which is also something to take into consideration when feeding your plants.
Ok so you have these chemicals – now molecules, which are groups of chemicals joined in a way that makes them able to join in with the water chemicals to become soluble, sloshing about in the soil. Well not quite sloshing because as all things have this electrical charge, either positive or negative, then the chemicals are hanging around with the soil chemicals and the water chemicals attract them over and like hanging off monkey bars in the playground they swap one rung for another. The root hair can’t take on soil particles but can take on water. But how?
Ok – I don’t know about you, but I need a break here. I don’t enjoy chemistry and I’m sure my old science teacher would look at my explanation and roll his eyes – but I’m not sitting an exam here and a vague understanding of the horrible bits is good enough for me. But we are safely through that bit and how the nutrients get in is kind of cool – once you know about the horrible bits.
Come again soon – for the actual how it gets in. I hope this is making sense to you.
Sarah the Gardener : o)
I don’t know about you but I needed a break from all that heavy sciency stuff. You should see what I have been looking into for us next! I do have to say it has been a great distraction from the fact we still don’t have a house. There have been a few delays – which to be honest was probably expected. Either way, the house will arrive soon and it will be much cheaper and much quicker than building a house. So I’m not complaining.
So while I wait, when I’m not losing my head in science, I’ve been processing my chillies from my container garden. There weren’t great quantities but enough to entertain me for an afternoon. We just don’t have the facilities for a glut right now. I decided to take you all with me in my cooking in the caravan arvo and I had a lot of fun. You can check it out here:
It is a great recipe, and really easy – even easier if you have a blender! So I hope you give it a go.
Come again soon – we’re back into some heavy science stuff to pass the time.
Sarah the Gardener : o)
On my journey to understanding my sandy soil from the plant to the soil, we have already found that the plant pretty much sucks up the water from the soil and releases it out of the leaves as water vapour in some kind of super pump delivering the nutrients along the way. There are other uses for the water in the plant, but we’re just interested in the bit that connects it to the soil.
The common line is ‘water and nutrients are absorbed from the soil’ but that isn’t good enough for me – I want to know how. Some soils are better hosts to this process than others and so if we understand how this happens then we can treat our soils in ways that can help and not harm the process.
This means we are still looking at the structure of the plant down in the roots, but there is also some chemistry in there and other complex scary sciency stuff, but if we step back and look at it in a more user-friendly way, it might make more sense. If we think of it in a space type action adventure, then it is even more interesting.
In the centre of the roots is the up and down elevators to the plant above with the phloem bringing the manufactured sugars down and if they are bringing them as far down as the roots it is likely to be stored for future use, like in spuds, carrots or turnips. Beside that is the xylem which whisks the water upward taking with it any nutrients that have been ‘absorbed’. This is wrapped with the endodermis that has within it the ultimate gate keeper as to who can enter the xylem and who can leave the phloem – the Casparian Strip. Like some kind of bouncer protecting the VIP area in a nightclub. And there goes my space analogy already… maybe it is like some kind of specialist Storm Trooper protecting the access way to the heart of the Death Star? I don’t know – my kids are the Star Wars experts. But the endodermis with its embedded Casparian Strip wraps around the pipes to create what is known as the vascular bundle and you can only get in if you’re on the list.
Beyond this central core is the cortex which has large cells that can be thought of like some kind or foyer or waiting room. The sugars from above can be stored here as starches but it is also where incoming waters and absorbed nutrients are escorted across the root as they make their way across the cortex to the vascular bundle as they await permission to head on up into the interior of the plant. In my head I see some kind of secure government department that once you clear the front doors you need some kind of staff member with a clipboard and a name tag dangling from their neck to take you to where you need to be. (I’ve never been in a place like that but seem something similar in the movies.)
Beyond the cortex is the epidermis that wraps around the whole lot in a waterproof layer in a single layer of cells. But not just any kind of protective layer – it has special cells with special jobs. Like the leaves it has stomata cells that open and close to allow gas exchange. But it is the root hairs we are interested in as these are the ones that do the ‘absorbing’.
The root hairs are single cells that elongate out from the epidermis along the length of the root and its branches and are the ones responsible for the all-important water and nutrient absorption. These cells are the hunters and gatherers of the plant cell community. They are microscopic, fragile and only last a few weeks, but the epidermis cells are constantly being replaced.
And that is the biology bit of understanding the soil. Giving myself an overview in my head I see these intrepid individuals (root hairs) risking life and limb going out to seek out the essential elements for life for their civilisation. These nutrients are then thoroughly checked for suitability and demand and then whisked up into the heart of the community on a wave transportation not dissimilar to being teleported to where it needs to be in some hi tech mail room organisational system, with the water being little more than the mechanics of the transport rather than essential in great quantities for hydration – although it does have essential for life uses for a portion of it.
So, you can sort of see some kind of space action movie thing going on… well it is a bit weak, you hopefully you get the picture. There are so many more amazing things going on in the plant to make it the functioning being that it is. But I’m just focusing on how it is connected to the soil.
Come again soon – because we now know how – but want to find out more about this ‘how’ business as ‘absorb’ seems a bit wishy washy to me.
Sarah the Gardener : o)
Just to recap – I am on a journey to understanding my sandy soil that has taken me into the murky depths of soil and plant science to find clarity. I am trying to understand the reason behind things, so it makes sense as to why we do things. Just saying plants absorb nutrients from the soil is all good and well when you have perfect soil, but when it needs help to ensure a perfect crop, understanding the mechanics behind it helps to make my actions as a gardener more effective. I’ve spent some time poking about on the great big internet and with each revelation of understanding I was like a toddler asking, ‘but why?’ Which took me deeper in my understanding of what is going on in this new land I am now the guardian of.
So today we are starting where I ended up in my research. My ‘but why’s’ took me on a journey from the soil to the plant, so explaining the way back should make it easier to understand.
Everyone knows plants get their energy from the sun and convert it to plant food in the leaves with photosynthesis. This starts being introduced to small kids at school – that and the life cycle of a monarch butterfly. I remember wearing out my best friend’s orange colouring in pencil on that project… opps sorry buddy. As my education progressed the layers of plant knowledge increased, and I can draw the internal structure of a leaf, its cell structure as well as the inside a chloroplast where the photosynthesis occurs within the cell with my eyes shut. It just stuck.
It is fascinating, and to understand the internal structure of the plant does more than just understand how it works, it also helps to understand the impact of how we treat the plants. For example, a common remedy for plant pests is to whip up a concoction which often includes liquid soap. So, the natural liquid soap to grab is dishwash liquid… its soapy, it’ll do. But the thing is, it isn’t soap – it is a detergent with loads of ingredients with the aim of stripping grease, fats, waxes and oils off your plates. It isn’t soap. Soap is made from fatty acids from animal fats or vegetable oils. I can draw the Triglyceride structure with my eyes shut too! (Triglycerides are the molecules we like to call fat and proper soap is made from them.) Insecticidal soaps, in water, kill some common soft bodied insects on contact and do little harm to the plant. However, if you know anything about leaf structure you will realise that most plants have a waxy layer to help prevent moisture loss from the leaves and to use a detergent soap instead of a proper fatty soap will strip this protective layer from the leaves making the plant more vulnerable to diseases. There are so many side tracking topics that are handy to know when delving into the complex lifestyles of our horticultural companions, but I need to come back to the facts of how plants operate in sandy soil.
Ok where were we. Plants create their own energy from the sun, carbon dioxide and water with photosynthesis, in the form of carbohydrate sugars, with oxygen as a by-product. The sugars are transported about the plant to the leaves, stems and roots in a pipe like network called the phloem. It is a one way system sending the sugars down the plant to where they are needed.
Beside the phloem is another pipe network called the xylem and it comes up from the roots and is the one we are more interested in, as part of our journey to understanding the soil. The xylem is the main pathway water takes through the plant, drawing up soil nutrients to take with it, to deliver them to where they are needed in the plant.
This water flow process is called Transpiration. Plants take up a considerable amount of water from the soil, but they don’t actually need all the water they absorb and most of it is lost through the pores in their leaves, called stomata, as water vapour. The main job for stomata is allow the carbon dioxide in for Photosynthesis as well as being a handy outlet for the water. This controlled loss of water in the leaves acts as a kind of pump to draw the water up from the roots with capillary action. As the moisture is lost more is drawn up into the leaf to replace it, pulling it upwards against the force of gravity and distributing soil nutrients with it as it goes and using what it needs for photosynthesis and then pretty much ejecting the rest. It is a pretty impressive system.
There is much more to it than I’ve outlined, but essentially what we are interested in is the water function – apart from having some specific uses within the plant, like in making energy and other things like keeping cells nice and plump so the plants stay upright and don’t wilt and other things. The way it is used like a giant conveyor belt to deliver the nutrients from the roots to the tops. A lack of water in the soil can interrupt this flow and cause harm to the plant.
So that is why it is important to have a soil that can retain water well, and why if I’m to have a successful garden I need to modify my sandy soil, because it isn’t all that good at holding on to water. And this is where I arrived when I asked, ‘what happens once the nutrients get in the plant?’
But we are always left with the fact – the roots absorb the nutrients and water. But my next questions were – that is all well and good, but how? It turned out this was really cool and could make a great space-based action hero cartoon if I was any good at drawing and stop motion filming.
Come again soon – I will try to explain my understanding the how’s behind this magic ‘absorption.’
Sarah the Gardener : o)