We are always in the mood for appropriate technology, especially when it is elegant and inexpensive – perfect for people! So when we heard about the Kon Tiki biochar kiln and how it makes inexpensive, copious biochar efficiently and with minimal smoke our little ears perked up.
Most biochar retorts we have seen are complicated affairs requiring external energy to heat the biomass stock material to the temperatures needed for pyrolysis, with fairly poor efficiency. Not so the Kon Tiki. It’s secret is in the shape (physics, friends). The inverted cone contains the fire in such a way that the biomass stock is not burnt up but the gases are, all without producing excess smoke. It uses no external heat source. And it’s simple to construct if you’re handy.
The link to the Kon Tiki description is here.
Now, by means of full disclosure, we admit that we have not tried the Kon Tiki kiln or other similar kilns. We do have our eye on one suited to backyard charcoal production – the CharCone – here.
If you can’t afford either of these options, it is possible to dig a pit the right shape and make biochar in it. See this presentation.
There is no end to trimming and pruning woody materials here on the Rancho. And given the success of biochar in a few garden beds, we are keen to spread it over larger areas. Several years ago we purchased some biochar for an experiment on new garden beds. This was right before the beginning of the Great California Drought and we were not able to follow through due to lack of irrigation water the last three summers. However, we did have enough left over biochar to dose one of our growing beds in the main garden. That bed has flourished, even more than the rest of our mineralized garden. It was not a controlled experiment, but the biochar seems to have helped. Biochar is supposed to aid:
All of these are useful in our loamy sand. This is in addition to biochar’s role in sequestration of carbon for the long term.
This certified Organic farm near Maricopa, California, growing blueberries in a soil-less media, has an oil well in the field! The lanes between the rows are suspiciously weed free. Surrounded by chemical agriculture for miles and miles, one has to wonder whether these blueberries taste like anything but oil and sand. Buyer beware – not all Organic farms are like the picture on the plastic clamshell!
Organics standards spell out what the farmer can’t use on their crops, period. They do not dictate diversity or pollinator habitat or whether the farm would be a place you would like to take your kids. The lesson here is that if you want your food to be a certain way (healthy, for example) you should know exactly where it comes from.
The best growers utilize both minerals and biology in their quest for excellence. These two major pathways for getting nutrients into the plant are not mutually exclusive – in fact they can support each other.
In the mineral pathway, nutrients enter the plant roots directly, without intervention of the soil micro-organisms. There are several ways this occurs, described in more detail in this post. In the biological pathway, microbes use soil minerals to build their bodies, but also receive food from the plant roots directly. When the microbes die or excrete, the resulting compounds can be absorbed directly by the plants. The plants feed the soil microbes who in turn feed the plant in a symbiotic relationship. Balanced and available soil minerals support this relationship.
There are three ways plants can absorb minerals directly: by mass flow, by diffusion or by root interception. Mass flow is the movement of dissolved nutrients into a plant as the plant absorbs water for transpiration. The process is responsible for most transport of nitrates, sulfates, calcium and magnesium. It requires that the nutrients be dissolved in water and enter the plants in ionic form, suspended in solution.
Diffusion is the movement of nutrients to the root surface in response to a concentration gradient. A high concentration in the soil solution and a low concentration at the root cause the nutrients to move to the root surface, where they can be taken up. This is important for the transport of phosphorus and potassium. If there is too much salinity in the soil, this process comes to a halt. That is why we pay close attention to the sodium levels in the soil test and even better, the conductivity. In general we want the conductivity to be under 2 mho/cm, but we don’t want conductivity to be zero – some energetic communication is essential.
Finally, root interception occurs when a root contacts soil colloids which contain nutrients. The root then absorbs the nutrients. It is an important mode of transport for calcium and magnesium, but in general is a minor pathway for nutrient transfer.
In the biological pathway, the soil life and the plant exchange nutrients in a symbiotic relationship. During plant growth, the roots transport sugars into the soil. These sugars provide food for soil microbes, who in turn multiply quickly in response to the food. The microbes extract minerals from the surrounding soil in order to build their bodies. When they poop or die, the microbe’s bodies are broken down into compounds that the plants can absorb. Microbe byproducts feed mineral nutrients to the plant via mass flow, diffusion, or root interception. Or, in the case of VAM, the mycorrhizae conduct water and minerals directly into the plant roots.
Capitalizing on the biological plant-soil fertility cycle has some distinct advantages. If you do not irrigate your crop, even a few weeks without rain at the wrong time can spell disaster. On the other hand, microbes can continue to work even in very dry conditions.
Almost all of the OMRI organic minerals OrganiCalc recommends are microbe friendly, encouraging microbes rather than inhibiting them. However, agricultural sulfur and copper sulfate deserve scrutiny.
Copper sulfate is a powerful fungicide, but the Biomin (4%) copper we recommend has no fungicidal properties.
OMRI 90% Ag Sulfur (Tiger Sulfur, for instance) is not without consequences. Often Ag Sulfur is the only way to remove excess cations, and restore balance to the soil. So, it has its uses, but we do have an application limit of 100 lbs/ac (which is not much) on this material because it does impact soil life.
Ag Sulfur is slow acting, usually taking over a year to do its work. Specialized microbes slowly convert the sulfur into sulfuric acid, which is toxic to most other microbes. Once in sulfuric acid form, the sulfur is free to form sulfates with excess minerals, which in turn can be leached by sufficient clean water. This effectively removes excess cations, bringing the soil into balance, and lowering the pH. There is a long history documenting improved plant health in soils with a pH between 6.9 and 6.0. With the addition of up to 100 lbs/ac Ag sulfur we slowly move mildly alkaline soils toward a lower pH.
Sometimes people confuse this process with another important function of sulfur. Sulfur is a required plant nutrient (sulfur works with nitrogen), and optimum quantities are 50 to 80 lbs/ac (depending on CEC). This sort of sulfur is best supplied by gypsum (calcium sulfate), or other sulfates, which do not harm microbes at all. Gypsum supplies about 1/5th the sulfur of Ag sulfur.
When we feed the soil, we feed the microbes who in turn feed the plant. When we feed the plant, we indirectly feed the microbes who in turn feed the plant.
If managed properly, certain species of plants can form a symbiotic relationships with vesicular arbuscular mycorrhizae (VAM) who scavenge both phosphorus and moisture from the surrounding soil and return it directly to the roots. In order for the plant to form this relationship it is critical that it not have ready access to soluble phosphorus early in its growth. Fertilizing with soluble phosphorus at the seedling stage will inhibit drought tolerance later in the season. Being mindful of this fact, we initiated a conversation with Dr. Christine Jones, who assured us rock phosphate has no ill effect on VAM. Many plants are capable of forming a relationship with VAM, but the cole crops (cabbage, broccoli, etc.) are not.
In 1997 a USDA research team led by Dr. Sara Wright discovered glomalin, which has revolutionized our understanding of how fertile soils are made. Her work has provided the foundation for others, including Dr. Christine Jones and John Kempf, who are engaged in building soil humus while growing crops and/or pasture. Her breakthrough is well documented in this very interesting article: http://agresearchmag.ars.usda.gov/2002/sep/soil.
How does one go about feeding the soil? A healthy soil has balanced minerals but does not contain traces of herbicides, fungicides, pesticides or chemical fertilizers, all of which are harmful to soil life. To feed the soil, balance the minerals and avoid chemicals. A healthy soil also contains organic matter, either from additions of compost or humates, or from cover crops and other living plants.
How does one go about feeding the plant? Besides feeding the soil, foliar feeding the right nutrients at the right time keeps plants growing rapidly. If plants are very, very healthy they will transfer their excess photosynthetic energy into lipids, which are stored in the soil for later use. These fatty compounds are too complex to be broken down by bacteria (in a process called mineralization), but are food for fungi. Fungal decomposition is an entirely different process, resulting in humification, which builds organic matter in the soil. This is an important topic, best suited to another post…
We’re in for another very dry year in California and much of the American West. Snowpack levels are extremely low in the Sierras. Rainfall has been a fraction of normal. A state of emergency has been declared in California and parts of Oregon and Washington. Water will be expensive, not very good and we’re almost sure to see water rationing. It’s not as bad as the photo of Death Valley above, but we’re in for a very dry summer. What can a gardener do?
Organic mulches that decompose into the soil are the best for the soil biology and the long term health of the garden. Unfortunately we need to be very cautious with the materials we buy or bring into our gardens. There is a real danger that contaminated compost, manure, straw, hay or grass clippings will destroy your garden and keep you from growing veggies for years. We know this from experience! Read on!
Sadly, some very toxic and persistent broadleaf herbicides are being used on grass family crops, golf courses, in ditches and under power lines. The first reported garden contamination occurred in England. Gardeners were using manure from herbivores pastured on land treated with these herbicides, and the compost made from the manure was killing their tomato and other vegetables. Another instance was in Seattle. The herbicide contaminated materials passed through a commercial composting operation, and ruined people’s gardens for years. These material also have contaminated straw from eastern Washington, where these herbicides are used to control Canadian thistle. These very persistent herbicides have the capacity to contaminate straw, hay, compost and grass clippings. They can pass through an animal intact and contaminate their manure. If these contaminants get into your garden they will stunt and kill your plants for years! If you are bringing in mulch materials that you don’t know the full history of, it pays to test the materials before risking your garden.
The herbicides are Picloram, Clopyralid and Aminopyralid but they are sold under the trade names of:
We use this procedure to test any imported material:
Better yet, also maintain a control.
The following alternative procedures are widely reported on the internet.
To test compost or manure…
Fill another three clean pots solely with commercial potting soil. These will be the untreated comparisons.
To test straw, hay or grass clippings…
In both tests there is a possibility that your pea or bean plants will not do well for reasons other than herbicide residue. Photos of herbicide contamination are on this Washington State University website.
In the vegetable garden we use a layer of compost or “proto-compost” (for example, garden waste or mushroom compost that hasn’t fully broken down yet – see picture at right) as a local mulch around the plants. The density of compost and proto-compost is good for holding moisture around seedlings or transplants and the part in contact with the soil gives the soil biology something to munch on.
Note: We don’t use vermicompost as a mulch — it belongs in moist soil below or near plant roots where the microbes in it can spread out and multiply.
Over this we spread a hefty layer of straw. Straw is the stem of grain plants (oats, barley, rice) after the seeds have been removed. Straw is not the same as hay. Hay is the stem and the seeds of plants and is usually grown as a feed for animals. The seeds in hay, even rotted hay, happily sprout and grow in the moist conditions under the mulch.
We also use a thin layer of broken down straw to cover the dirt over newly planted seeds (last years straw works well for this). The bits of straw keep the sun off the soil and help keep it from drying out and crusting over.
Leaves make a great mulch, as does pine “straw” (fallen pine needles).
Grass clippings are dangerous! They have enough nitrogen to heat up and literally burn your plants if fresh clippings are used. Dry your clippings before use or keep them a few inches away from the plants.
Wood chips do not work well in the vegetable garden near the plants. They are great for mulching paths, and around raised beds if you got ’em. The problem is that when they decompose, they tie up nitrogen, and nitrogen is one of the most difficult nutrients to make available in an organic garden. The same is true for sawdust.
We saw one very inspiring YouTube of a man in Washington state who mulched his entire garden with wood chips. It looked great and the plants looked great. Then he let it slip — he’d put a 6″ layer of composted chicken manure under the wood chips. Chicken manure is one of the highest nitrogen manures around. Apparently it had enough nitrogen to supply the decomposing wood chips and grow a good garden.
Ideally every part of the garden will be mulched, including the paths and surroundings. There is something to be said for the communication that happens between plants when all of the soil is covered.
Under the right conditions many plant species will form a symbiotic relationship with a type of soil fungi (arbuscular mycorrhizae or AM). The fungi penetrate the roots of the plants and grow out into the soil, bringing back minerals and water for the plants. The plants in turn feed the fungi carbon. The fungi acts like a second set of roots, providing some degree of drought tolerance.
AM tends to be comparatively sparse in soils with adequate minerals and moisture, probably because under abundant conditions the plants are not feeding them carbon to stimulate their growth. For those of us who keep our soil well mineralized and moist, AM are our insurance policy. If anything comes up short, our plants can send out the AM to get it.
Tilling (plowing, rototilling, spading, etc.) breaks up the fungal strands, but they grow back in about a month.
About 80% of plant species form an association with AM. Garden plants that do not are:
Cabbage, broccoli, cauliflower, radishes, turnips, kale, bok choi, and other plants in the brassica family.
Endomycorrihzal fungi is sold in a powdered form for inoculation of soils. We have not been able to tell one way or the other whether the inoculant works.
Most organic growers have used aerobic composting to process raw organic matter, including food scraps, into a useful soil amendment – compost. Composting is a fairly intensive process requiring the ingredients to have the correct C/N ratio in order to heat up yet decompose aerobically. Aerobic composting recycles only about 50% of the carbon in the starting material, losing the rest to the atmosphere as greenhouse gases. Compost piles need to be turned to keep the contents oxygenated and working quickly, plus they require a fair amount of space. And in our experience, they can attract rodents if food scraps are used.
Enter vermiculture and bokashi fermentation as alternatives to composting, especially in small gardens. Both methods are used to rapidly process food waste into a soil amendment. Both have their drawbacks; worms are picky about what they eat and do not eat raw food scraps very quickly, preferring rotten food to fresh. Bokashi fermented scraps should be used fairly quickly, and are wet and unpleasant to handle.
Now enter Bokashi Vermiculture. We put the two processes together to get the best of both worlds. The result is a stable, high nitrogen soil amendment. Simply put, we use bokashi fermentation to process two vegetarian household’s fruit and vegetable kitchen waste, then feed the fermented mess to our worms who seem to thrive on it. The worms rapidly process the bokashi fermentation product into vermicompost. From kitchen to vermicompost takes less than 8 weeks, which means we get more vermicompost in less time. It’s not a new idea, but then again no one else seems to be doing it.
Both bokashi fermentation and vermicomposting conserve nitrogen compared to aerobic composting, and the result is a high nitrogen, stable soil amendment. A handful under transplants in mineralized soil results in great veggies, like the Chinese cabbage in the picture below (pic taken today).
There are plenty of places to buy worm bins and bokashi fermenters. We don’t use either of those, but instead put ours together out of inexpensive parts as described below. Ours is not a system for apartment living, but it could be scaled up or down depending on available space and raw organic matter.
We have a simple 3′ x 5′ worm bin that is built into the side of a hill. The bottom and sides of the bin are cement backer board pieces left over from a bathroom tile project. The cement board does not absorb water and is solid on the bottom, helping keep the worms moist and any burrowing critters out. Anything solid could be used for the floor; we just used what was around. The cover is a plastic tarp with a second acrylic panel cover to help keep the sun from rotting the tarp. Being built into the hill helps to moderate the temperature in the bin – worms do their best between 70 – 80F but they survive from 38F to 95F. This bin has yet to go through a winter, although our coastal California winters are hardly cold. If we lived in a cold climate we might cover the whole thing with a thick layer of straw and let the worms go dormant for the cold season. If we lived in a wet climate we might not build it into a hill, and take more care to keep rain out.
Our worms are red wigglers, a.k.a. compost worms, Eisenia fetida. Our first handful of worms came from a friend, eventually multiplying from just a few to really a lot. Reproduction does not happen overnight though, even though one adult worm can ultimately produce 10 babies a week. It takes 3 – 5 months for a worm to grow from egg to sexual maturity, so there can be a delay if you don’t start with enough worms. Other native decomposers like pillbugs, sowbugs and earwigs live in our bin, as do some extremely healthy looking lizards. In the picture to the right, uneaten bokashi fermented veggies are visible, which is why the worms are there.
We started our worm careers with a more traditional worm bin, the kind with stackable trays. This worked when we were feeding the worms just a few small scraps. The trouble is that most of our scraps are large (outer cabbage leaves, onion peels, carrot tops) and the little trays could not handle them. And although the tray system worked, it did not produce very much vermicompost. We consider our in-ground bin to be a real improvement.
To harvest worm castings we move the darker, denser material to one side of the bin with a shovel. This allows the vermicompost material to dry out a little and the worms to move back to the center of the pile. After a couple of weeks we sift these castings into a bucket through an old nursery flat (about 1/2″ mesh) to get any undigested large chunks out like mango seeds or avocado seeds. These go back in pile for further work by the worms.
The worms are ready to be fed when most of their food in a certain area has turned into dark castings. We shovel out the darker castings and worms leaving a layer of worms and castings at the bottom, then dump in up to 5 gallons of fermented bokashi, then cover the raw bokashi entirely with dark castings and worms. If there are not enough dark castings to cover the worms with, they are not ready to be fed. If dead leaves or other decaying plant material is available, it could be layered in with the bokashi.
At the same time we are feeding, we “fluff up” the active feeding sections of the pile by gently turning it with a shovel. The idea is to make sure that there are no large sections of undigested bokashi. Even though the bokashi ferment is anaerobic, the worms like to eat aerobicly digested food. It does not take long to convert the bokashi to worm food – contact with a little air will do it. Be forewarned; if you are feeding straight bokashi, this process is not completely smell free! The addition of dead leaves or partially decomposed regular compost at bokashi feeding time will make the “fluff” process more pleasant.
There are many websites and stores now that sell bokashi fermentation supplies; we even saw a bokashi fermenter for sale at Whole Foods. These systems may work very well, but we made our own, including our initial batch of EM1 starter microbes.
Traditional bokashi composting is an anaerobic process using EM1 microbes to rapidly ferment raw organic matter (more about the microbes later). The raw organic matter, in our case kitchen scraps, is mixed with EM1 inoculated roughage, in our case wheat bran, and pushed down to remove all air (more about the bran later). The resulting mix is fermented in a sealed container for several weeks at room temperature.
The picture at right shows a brewing bucket with it’s inner plastic wrap seal off. We use a 5 gallon bucket with a sealable lid and cover the bokashi with a layer of thick plastic wrap before putting the lid on. Note that 5 gallons of solid food scraps and bran is heavy – it can weigh up to 40 pounds. It is possible to find smaller buckets or not fill them all the way up to reduce the weight.
Bokashi needs anaerobic conditions (no oxygen) and a little air can cause it to turn black, go bad and really stink. Properly fermented bokashi looks like sauerkraut, with all the original bits still identifiable, and has a vinegary smell that is no worse than sauerkraut. Commercial bokashi buckets have a drain at the bottom to remove liquid. We haven’t done that on ours; we just use solid buckets, and the bran helps to soak up any extra moisture.
We keep up to 4 buckets brewing while 2 buckets are being filled with new scraps. It takes about 2 weeks for us to fill a bucket, then the bokashi scraps ferment in the bucket for another 2 – 4 weeks, depending on whether the worms are ready to be fed or not. The bokashi bucket being filled is kept outside (the garage would be another candidate spot) and we keep a separate container in the kitchen to accumulate scraps. We also keep a container of bokashi bran to add to the kitchen scrap container. It helps to keep odors down in the kitchen. When we put scraps in the kitchen container, we add a little bran.
Bokashi serum is used to inoculate bokashi bran, which is used to inoculate the kitchen scraps for the bokashi fermentation.
Put the rice and water in the jar and shake vigorously until the water is white and cloudy.
Strain off the rice.
Leave the water in the jar with the lid on loosely
Leave in a dark cool place for 5 – 7 days
Assemble these ingredients
Mix the water and milk in the jar.
Leave the lid on loosely, !very important!, it can explode otherwise
Leave in a cool dark place for 5-7 days
Assemble these ingredients
The milk should have separated into a curd on top and a clear yellow liquid below.
A little white mold is okay on the curd but black mold is not okay.
Remove the curd – you can feed it to animals.
Strain out the yellow liquid — this is the serum.
Dissolve the molasses in the serum.
The serum can be stored in the refrigerator for up to a year.
The serum has other uses as a foliar spray or soil drench. More on this in a future post…
We don’t know if this recipe results in the same mix of microbes as EM1(TM) – we assume it does not. However we’ve tried both, and they both seem to work fine for making bokashi bran.
We buy wheat bran in a 50 lb. sack for about $20 at our local feed store. Other people use newspaper or sawdust instead of bran but we haven’t tried that yet.
Assemble these ingredients
This is about twice the water/serum/molasses recommended in other recipes on the web. Perhaps the wheat bran we can buy is extra dry? You may want to start with half the water, serum and molasses and see how moist your bran mix is before adding more.
Most recipes call for the use of de-chlorinated water (or well water or rain water) because chlorine can kill the microbes you’re trying to propogate. We’ve had to use chlorinated water at times and the process still worked. We now have a de-chlorinating filter on a hose bib, so we use water from the filter.
Mix the blackstrap molasses in a little hot water to dissolve it. Dilute with cold water or let it cool to less than 110F (it will feel just warm on the inside of your wrist). The serum microbes will be killed by temperatures over 110F.
Mix the serum, cooled dissolved molasses and water together. Add to the bran while stirring with your hand.
You’ve added enough liquid when all the bran is moist and a handful just sticks together when squeezed.
Put the bran in the sealable container, pushing it down to remove all air.
Cover the top of the bran with plastic wrap to keep air out.
Seal the lid.
Store in a cool place for 2-3 weeks
When you open the lid of your inoculated bran, it should have a vinegar like smell. A bit of white mold is okay.
We dry our bran on a tarp outside, turning it several times a day to get all the parts dry. It takes 2-3 days drying time, even in our California sun. The picture at right shows 10 lbs of bran drying on a 4′ x 6′ tarp. If it is not entirely dry when you put it away it can grow mold, so it’s best to get it thoroughly dry.
April 24, 2014 was the last rain here at Rancho Reinheimer in Arroyo Grande CA until last night, halloween, October 31, 2014 when it dropped 1.85 inches. Showers are continuing today, bringing us up over 2 inches for the storm. That’s already 1/3 of last winter’s total rainfall.
Rain is great fertilizer here. Maybe it’s the extra nitrogen in the water that accumulates as it falls through the atmosphere. Maybe it’s the lack of salts, chlorine and dissolved minerals that’s in our irrigation water (we don’t have a well — we have to use treated city water on the garden). The trees, the frogs, the birds are all out celebrating today. Termites are taking the opportunity to spread their wings and fly away in droves on the fresh breeze.
Today is October 18th and we’re taking it easy at home here in sunny California. Today is the first day we have ever seen our Santa Rosa plum tree bloom in October. But there it is, blooming its heart out as if the sunny 78F day we are enjoying was occurring in March.
This week the ocean temperature off the coast here set a new all time high record. Form our local forecaster, John Lindsey: “Last evening, we may have tied or even broken the all-time seawater temperature record along the Pecho Coast of San Luis Obispo County.” Water temperatures this warm usually mean an El Nino year, with a rainy winter expected. California could really use the rain after two years of severe drought, but they say that it may not materialize. It seems that the ocean is warm all over and it takes some cold water mixed with the warm to bring us the rain.
As the climate heats up, ocean temperatures are rising, along with atmospheric temperatures. Of course much of the increase in carbon dioxide in the atmosphere is due to the burning of fossil fuels. Did you know that a significant percentage is also due to loss of organic matter in the topsoil? And due to our present industrial farming practices?
Soils can and should be a repository of carbon — building humus is the key.
Graeme Sait makes the link between soil health, human health and the environment in this interesting TedX talk:
We live where it is windy in the afternoon, with intense sun, cool at night, foggy until late some mornings and did I mention the rampaging deer? Our native plants love it — oak trees grow like weeds here. But some of the veggies are tender and they prefer to live a more moderate lifestyle.
Enter the floating row cover tunnel. These are small hoop houses for the garden, but instead of covering them with plastic, Erica covers them with floating row cover, brand name Agribon to be exact.
To construct them she buys 10 foot long sections of plastic electrical conduit — the cheapest kind. Assembly of the tunnel is better as a two person job the first time. We have soft soil so we can just insert the ends of the conduit into the ground. If the soil was hard we might need to pound in a piece of rebar to slide the conduit over. Once one side is inserted, bend the conduit in a hoop and insert it on the other side of the bed. Hoops are placed about every 4 feet along the bed. A straight piece of conduit tied in place along the top will help to stiffen the structure and hold the floating row cover fabric.
Erica buys the 10 foot wide rolls of floating row cover fabric, Agribon AG-19 (http://www.johnnyseeds.com/p-8418-agribon-ag-19-row-cover-10-x-50.aspx), which is expensive but worth it to us for the increase in yield. The only fabric available now is spun bonded and it does not last more than two seasons. There was a time when woven row cover fabric was available and it was much more durable, but alas, those days are gone. She cuts off a length of fabric long enough to cover the tunnel and the ends. The fabric is held on by giant metal clips from the office store, the largest size they make. These are much cheaper than the clips from the garden store.
Since the local deer have grown so fond of tomato vines she always grows her tomatoes under tunnels. The tunnels are large enough to hold the plants even when caged. In extreme deer years, the row cover needs to stay on throughout the season. As soon as a tomato vine pokes through a hole in the fabric, it gets pruned back.
Cucumbers love it under the tunnels and we now get bumper crops in a small area. Since the tunnels provide some frost protection, they are also good for early zucchini until the plant outgrows it.
The taste of tree-ripened nutrient-dense fruit is one of the great joys in my life. I love a flavorful apple at the peak of ripeness, the sweetness of a juicy custard-textured persimmon, a glass of vibrant orange juice. Picking ripe wild blackberries was a late summer ritual in western Oregon where I grew up. Now I have a new ritual; every year I plant fruit trees.
Here on the Central Coast of California we are blessed with a climate that allows us to grow apples and avocados, citrus and plums, apricots and persimmons, pears and berries. We have just enough chill hours in the winter to grow apples and pears, but not the freezing weather that would kill citrus and avocados (although the 26 degree nights last winter did take their toll by severely trimming back our most frost sensitive lime and avocado trees).
Fruit trees and citrus are an excellent indicator of topsoil and subsoil deficiencies. Since we are growing in sandy, low CEC soil here at Rancho Reinheimer, I have become a connoisseur of mineral deficiency descriptions and photos, searching for the “silver bullet” that will cause my trees to look like those in the nearby commercial orchards. It is this futile search for the “silver bullet” that originally led me to the use of soil testing and mineral balancing, but that’s a different story.
The long and the short of it is, deficiencies can and do show up in similar ways for different types of plants. They are an interesting indicator of how minerals move or don’t move in the plant. The pH of the soil can also affect availability of certain nutrients in the soil and can prevent their uptake in the plant. For example, high pH (>7.5) can block the uptake of iron.
Many of the pictures of nutrient deficient plants shown below have been taken under laboratory conditions, where just one nutrient at a time was withheld. Insect damage or disease symptoms can also look like nutrient deficiencies! Or a plant may suffer from multiple deficiencies, adding to the confusion.
Any diagnosis of a nutrient deficiency should only be made on the basis of a tissue test – a test where leaves or other plant parts are tested for nutrient content (it is best to test a control “healthy” sample at the same time). The instructions for doing a tissue test are on the test labs’ web site.
The pictures below are categorized by nutrient with references at the bottom of the post.
Nitrogen is one of the major nutrients needed by plants — it is used to make chlorophyll — and it is one of the most difficult to find organic sources for. A deficiency can result in yellowing of older leaves first as nitrogen is translocated to new growth in the plant. Stunting of growth can also occur. Different types of plant exhibit different symptoms — not all plant turn yellow.
Sulfur deficiencies look a lot like nitrogen deficiencies however sulfur deficiency affects new growth first because sulfur does not translocate easily in the plant.
Phosphorus deficiency can occur in cool weather. Our young tomato plants seem to be especially susceptible in early spring. It is characterized by a red or purple cast on new leaves and poor, stunted growth.
Calcium aids in cell wall strength in the plant. When deficient it can contribute to blossom end rot in tomatoes and corky spots in apples.
Magnesium can be deficient in certain soils but certainly not in ours. As with all deficiencies, it is best to have the results of a soil test and tissue test in hand before treating the symptom.
Potassium deficiency is not usually a problem for organic growers who apply composted manure, since manure is a good source of available potassium. Potassium deficiency shows up in the edges of the leaves first.
Manganese deficiency produces a leaf yellowing similar to zinc deficiency where the veins of the leaves remain green while the part between the veins turns yellow.
Iron deficiency tends to occur in high pH soil, where the pH is higher than 7.0 or in soils that are severely imbalanced. Its symptoms appear as a yellowing of the leaves in a manner similar to zinc or manganese deficiency, usually with green veins remaining.
In the mineral world they say that calcium is the trucker (in that it moves all the other minerals) but boron is the truck driver. This is apparent in the pictures of boron deficient fruits and trees. Somewhere along the line the truck has gone off the road, resulting in strange shapes, hollow or hard cores and variable leaves.
Boron is mobile in the soil and subject to leaching.
Zinc deficiency causes a symptom called “little leaf” where new leafs are abnormally small and causes a yellowing of the leaf between the ribs, similar to manganese deficiency but with less smooth edges.
Copper compounds are often used in the orchard in organically approved sprays (and in conventional sprays) that are used to control fungal disease. It is immobile in the soil, so if copper sprays have been used in the past, it is worth doing a soil test to determine the amount of copper present. Because of its immobility, copper tends to build up and can reach toxic or at least unbalanced levels. However, some soils are deficient in copper. Before doing a soil application it is worth considering whether copper would not be better applied as a fungal disease preventative spray.
We’ve got a great example of the effects of mineralization and proper fertilization on citrus. The tree on the left is next to the vegetable garden which we use as a demonstration of mineralization, and from which we get nearly all of our veggies, The tree undoubtedly has its roots in the garden since it receives no supplemental water or fertilizer. The tree on the right is about 100 feet away from the garden and despite getting supplemental water and an multiple “silver bullet” fertilization attempts a year, always looks a little sickly.
Last year at Grow Abundant Gardens we did about 1000 OrganiCalc recommendations. We’ve heard of good results from some of you. We are very interested in all of your experiences.
We have improved OrganiCalc substantially since we introduced it about 16 months ago. Nitrogen, a key ingredient, was listed with the other recommendations early on. Our latest improvements include an option to reduce the phosphorus target by 50% in order to save cost on large areas.
We have also introduced a new responsive web site and a new General Mineralization Recommendation document.
Thanks for your support.
Erica and Alice
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