Friday, May 23, 2014

Where did my Calcium go?

Despite the garden being reasonably successful over recent months, I have been noticing and feeling the overall health of the garden to be declining. Many plants seem to be growing slower and performing poorly, with a greater increase in disease and pests. Last year I was drowning in zucchini and silverbeet, this year barely enough. Corn performed poorly despite being planted on compost sites, beetroot are all quite small, broccoli look terribly sick, and peas are wilting away before they have reached maturity. However the topsoil still looks and feels beautiful.

In April I blogged about how I was having an infestation of mallow weed, and how I questioned what this was telling me. From a bit of research, and some great reader comments, I started to believe the problem was related to a calcium deficiency. To help confirm this I decided to do a pH test.

The children helped me perform a pH test using a chemical based kit with a colour chart. According to my son it was 5.5, according to my daughter 5. Considering males are not as good at colour identification as females due to having less eye cone cells, I thought it best to trust my daughter. Regardless both 5 and 5.5 are considered quite acidic, with 6.5 considered best for most vegetables.

Soil pH is a measurement between how much hydrogen the soil contains compared to the amount of other nutrients such as calcium, magnesium, sodium, etc. When one or many of the nutrients are out of balance the pH level shifts from neutral and becomes either acidic or alkaline. The really important thing to understand here is that a pH test does not tell you which one of these nutrients your soil is deficient in. It is only an indicator to a possible imbalance. And this is where you have to be really careful. Adding dolomite because of assuming you have magnesium deficiency, when in fact you only have a calcium issue, may result in raising magnesium to a toxic level. But it gets even more complex...

From what I have been reading, calcium is in competition with other nutrients such as sodium, potassium, magnesium, ammonium, iron, and aluminum for uptake by the plants. Meaning what appears to be a calcium deficiency may in fact be one of the others blocking calcium uptake. For example a high level of sodium can displace the calcium and cause calcium leaching. Iron and aluminum can combine with the calcium and form insoluble compounds. And that’s just a couple of examples of the complexity.

So with all this complexity how was I going to know if I had calcium deficiency?

Well… in one of those lightbulb moments the answer dawned on me. I was collecting the chicken eggs, as I do, when I noticed that both eggs were cracked, and it was at this moment the lightbulb went on. You see... for a number of months now I have been aware that the eggshells have been becoming weaker and weaker, sometimes even breaking under the light pressure of being picked up. And of course why would the eggshells be weak? You got it… lack of calcium. This also helped to explain a major drop in production.

One very important thing about keeping chickens that I had failed to understand, was that chickens need a heavy source of calcium in their diet, such as shell grit. I felt like a bit of an idiot - it now sounds so obvious that constant egg production would require considerable calcium. I do hope the recent death of Panda was not also caused by this.

After pondering all this, I have come up with the following theory (refer to above picture):

The plants consume calcium from the soil. The chickens then eat the plants, and calcium direct from the soil. The calcium is then used to make eggs. The eggs are cracked open and the shells returned to soil - making a perfect loop. However the inside of an egg also contains considerable calcium - enough to create the whole skeletal system, claws and beak of a baby chick. This part of the egg is eaten by me and other members of my family, and thus never ends up cycling back into the garden. Considering chickens have been working this garden without shell grit for over three years, and have probably laid around 1000 eggs, I feel my theory sounds quite plausible.

Following Linda Woodrow's advice, my long term strategy is to do what I should have been doing in the first place and feed the chickens shell grit. In the short term to quickly get the garden back to performing, she recommended I apply agricultural lime. Which I have now done. I am now looking forward to some happier plants, and I am sure so much happier chickens.


  1. Jason, I really enjoy your posts. I've been thinking along similar lines in my garden and you've reminded me to start with the basics - a ph test!

    1. I am please to hear you found the post useful. I would love to know what you find out.

  2. Nice bit of deduction, Jason. I give my chickens shell grit, but although a calcium source, it's main purpose is to help grind up food in the gizzard. I also recycle their eggshells back into them via their food.

    I wash the eggshells and put them aside till I have quite a few, then give them a minute in the microwave to kill off any bugs and put them through a mincer till they're nice and fine (food processor would do as well), then mix them back into the chicken's food.

    My chooks love yoghurt and that's also a way of increasing their calcium intake.

    1. Interesting about putting the eggshells in the microwave. I have heard about this before but never knew why. My girls love yoghurt too. I also let old milk go chunky, and they really love that.

  3. Hi Jason, theories are fine if they are based in fact, not assumptions and generalisations. eg Tetrachromacy is only found in women, though not a lot of women have it and it is blindingly obvious when they do.
    Your daughter may indeed be right, but due to its logarithmic scale there is a world of difference between Ph 5.5 and 5.0. Ag lime will help at 5.5 but you may need to do some foliar applications at 5.0 while thing start to happen in your soil.

    Looking at your photos, your garden looks...neat and tidy, dry high carbon mulch and shallow rooted plants, the mallow is accessing nutrients that have leeched away from the topsoil, that is where your calcium has gone, down!

    Chickens are a whole different story, honestly, unless you garden specifically for the chickens, deep rooted nutrient rich weeds, compost and masses of invertebrates they will still need supplementation.
    The first thing to understand is chickens need a constant supply of small sharp stones for their gizzard, that is their teeth, if they cant grind their food and shell grit they get little nutrition from it and starve.
    Chickens wake up at dawn starving hungry and need to snack at least every two hours because their energy needs are high and stomachs are tiny.
    Chickens need a shell grit container so they can eat extra calcium when they need it, only having calcium in their pellets will result in chickens overeating carbs and getting fat trying to get enough calcium. It is the worst of both worlds, struggling to lay an egg because of muscle spasms due to low calcium made even harder from being overweight.
    Get these three things right and your chickens will be lively and lay lots of armour-plated eggs without breaking a sweat (for at least a decade).

    1. Steve, your opening line has hurt my feeling - making me feel unworthy of having and presenting my personal ideas. I did state "My" theory, and have never made claim of being an expert. However the rest of your comment is wonderful information that I highly appreciate. You have got me thinking... having more theories :)

  4. This happened in our garden years ago , where the nutrition dropped in the soil. I never really believed that could happen until I saw it for my own eyes, suddenly my soil wouldn't grow anything- now we know we always had extra natural organic matter and keep building it up. Scary to think that main stream big agricultural gardens must just keep adding artificial fertilisers to do the same thing.

    1. This problem I think is quite common, and I suspect the prime cause of people stopping gardening - thinking it is too hard. Not me though. I look forward to posting back when the garden is thriving again. It is reassuring to hear from others who have had similar problem and found solutions. Thanks.

  5. I apologise sincerely for hurting your feelings, entirely my fault, I edited the sentence down to make it concise and failed to see the context had changed. It was meant to say "We" (as in people) make generalisations and assumptions that completely change our understanding of how thing work.
    I dont expect you as a gardener to have a full working knowledge of soil. I expect someone like me (a farmer) to be able to quote the nitrogen cycle chapter and verse. Be able to demonstrate how the nitrates formed from ammonia and urea bypass plants, bond with the calcium and leave behind an acid and why the Adelaide hills and plains climate makes that area particularly susceptible.
    A farmer will lose 1.2kg of calcium out the gate for every tonne of wheat he sells but it is quite possible to tie-up 100Kg per hectare in a season, due to nitrates, as a direct result of the way he/she farms. A veg patch will react in a similar fashion with the added problem that a lot of veggies we grow are very sensitive to low calcium availability.

    I expect this same standard of information to be available from gardening experts to the general public, instead we get we get told to toss a couple of handfuls of lime on before we plant (more than a tonne to the hectare each year) to "sweeten the soil" or "balance the earth". I dont think it is possible for any home gardener to come to any logical conclusions from that kind of statement.
    As far as gardening and animal husbandry problems, I would regard this as barely a speed bump on the road for you, very easily fixed.
    I managed to kill my rhubarb crowns for seven seasons in a row before I worked out what I was doing wrong.

    1. This is great information Steve that I really appreciate. If I am understanding correctly my soil has become acidic due to adding too much ammonia/nitrogen rich cow manure - especially considering the commercial manure I am using has probably been soaked in urine. Thus the solution to my problem is to back off on the use of cow manure - especially considering I already have chicken manure being added - and add some lime to get things back into balance.

  6. Well, this conversation has my interest peaked. I just started a raised bed with peat, organic garden soil, sand and compost/manure mix. it is 10 inches deep. My plants (which I bought in peat pots) are not happy. My question is can you have too much agricultural lime? I have subscribed to your blog and hope to learn more. Thansk

    1. Yes I believe you can have to much lime, this would make the soil become alkaline. If you have just recently made this soil perhaps it just needs a bit time to balance itself. As soil is so complex I feel it is better to keep it simple and not try and mix to many different components together. Perform a test - get a large pot and just use the organic garden soil, and see what happens. If that works you may need to start again with what's in the raised bed - replacing it with just pure garden soil.

  7. My mother grew up during the Great Depression in the US. This is how she told me they did this almost 100 years ago. This is what we did in the 1950s and what I do now. I passed this by a PhD in Poultry Science. He assured me my technique and reasoning was correct.

    Don't wash the inside of the egg shells. There are nutrients in the goo in the shell. Let them dry. I put them in a disposable pie pan on the stove. Put the pan of shells in the oven when you have finished baking something. Do not burn the eggshells. The reason we browned the eggshells slightly is to keep dogs or chickens from eating the eggs before they have been collected. "Cooking the eggshells changed the smell and taste. I just put the eggshells in a plastic bag and crush them. Of course, the blender or whatever works.

    For a while, my hens just left the eggshells. So, I just mix the crushed shells into something they like, like gravy or leftover sweet potatoes.

    Eggshells give hens grit and calcium. The membrane in the shell is protein, good for a chick in the shell or for chicks and chickens in the yard or for the dog or your child.

    The PhD went to Russia. In one town the eggshells were reserved for children for the calcium the needed in their diets. This may seem gross, but calcium in eggshells might save a poor child's life or at least contribute to the child's health. Rickets/bone deformation. There are other symptoms for calcium deficiency, even in adults.

    Too much yogurt or any other milk products are not good for egg production, but I forgot why.

    Sprinkle crushed egg shells around your tomato plants. It will prevent blossom end rot. You can put some in the hole before you plant.

    My blog is sort of dead, but I am reviving it.

    1. For the children in Russia, the eggshells were ground fine, probably with a mortar and pestle. In a case of not being able to get my child enough calcium, I would not hesitate to get eggshells into my child. Of course, putting the eggs into an oven for just a bit would kill any pathogens.

      My chickens love scrambled eggs with the crushed shells.

    2. Okay, I will stop after this. I have had hens for five years and have never given them crushed shell. Their shells are hard. The eggshells provide grit and calcium.

  8. Apologies for the delay in replying,
    Hi Jason, I dont think animal manures or ammonia fertilizer are the root cause here. What we often forget is this cycling of nutrients is completely biological, microbes and bacteria are doing all the heavy lifting, without these guys nothing happens. What I think is happening is that your gardens microbe population crashes over summer then tries to recover but starves for food then this reduced population crashes again the next year and so on.

    Now you add ammonia to this small microbe population with very few plants to receive the nitrogen produced, it has to go somewhere and then we get into this death spiral of leeching and acidity.

    The lime does two things, it raises the Ph giving a more microbe friendly environment and it provides a buffer of material that can used to react with these acidic materials that are left in the soil. Lime takes a long time to work and the worse the condition of the soil the longer it takes, in a garden situation where the cost of applying lime is low the more often it is applied the better.

    So that gets things back to the starting point in all of this.
    Where do you go from there? I think a healthy active soil should handle the chicken manure no trouble at all with minimal acid forming it should also be able to hold a large amount of water close to the surface.
    In my mind the quickest way to a healthy soil is to feed microbes their favorite food, green waste and give them a place to live, around plant roots and strive for a highly biologically active soil. Dry mulches, grass and tree waste are a great long term investment but very few things really thrive (apart from fungi) when this is their only diet.

    As an experiment I have been chopping some weeds back every time they get to mid calf high/knee high and letting the prunings lay on the ground. I am up to my 20th cut since mid February and the soil has really started to kick on in the last month!
    Perhaps you would benefit from a square foot gardening approach and maybe a wicking bed for some plants that really take a beating in summer.
    I dont have any luck with the traditional top down deep watering idea, it seems to wash all the good stuff away and kill everything quicker.

    Regards Steve


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