Why Mulch a Temporarily Unused Garden?

"S" emailed me and asked about why I bothered to mulch the soil in the greenhouse that isn't being used at the moment. She didn't see the sense of wasting the mulch or wasting my time. 

Actually "S", that's a great question. And by the way, you'll soon see that it isn't waste at all, at least not from the point of view that I'm coming from. 

Ok. First question to consider......why do I use mulch? 

1- to control weed regrowth

2- to retain soil moisture

3- to protect the soil microbes

4- to provide nutrients to the plants

5- to retain soil so that it doesn't erode or blow away

6- to feed the worms 

If you noticed, I applied water to the greenhouse soil prior to applying mulch. That's should give you a big hint. 

The soil in the greenhouse is fairly young. I'm in the process of building it up. In order to get a good soil ecology going, I've been using generous amounts of fresh compost, supplementing that with livestock manures and urine. To create a preferred environment for soil life, I've been keeping the soil moist and shaded. This has meant watering once or twice a week plus keeping the soil surface covered with mulch. If soil drys out or bakes, I'd be losing much of the soil microbes and other soil life (worms, springtails, etc). The soil life is what decomposes the compost and manure teas, thus eventually providing plant nutrients. It's actually a complex cycle, but basically that's what's going on. 

By covering the soil with mulch, even though I'm not presently growing a crop in the greenhouse, the soil life is preserved and is busily doing its thing. It's in somewhat of a holding pattern since there are no actively growing plant roots. But by being evenly moist and protected from sun, the soil life will do fine until I plant the next crop in the next week or so. The soil life will be able to re-establish their colonies and network, thus recovering from the light tilling by the time the seedlings start to grow. 

So "S", even though I'm not growing an edible crop, I am growing a vast colony of soil life. I utilize this soil life in place of commercial fertilizers. So having a thriving soil life community is extremely important to me. Even with an edible crop, I will tend the greenhouse soil, keeping it moist, shaded, and full of food for the soil life. 

Soil : Till vs No-Till

The past couple days I've been super enthusiastic about getting the garden going full speed ahead. So after preparing a couple of garden sections for replanting, I decided to lightly till under one of the adjacent macadamia nut trees in order to plant a ground cover there. There's some background......

10 years ago I planted some baby macadamia nut trees. I did nothing the change or improve the soil, I simply planted the trees. Since that time I have done no tilling around the trees at all. But I have kept a constant mulch covering. Sometimes it is grass clippings. At other times it's compost. I'd venture to guess that fresh mulch was added 4 to 6 times a year, as needed to keep the ground covered. About twice a year I watered the trees well with manure tea made from composted manures. I sometimes also used diluted urine solution, but I honestly don't recall how often it was applied. 

So today I raked off the mulch and tilled the top couple inches. I was surprised to see that the soil didn't look much different than when I started 10 years ago. Even with all that applied mulch, the soil was still light red and very cindery. It was granular and did not have visual organic content. Only the top 1/2" right under the mulch was dark and looking like garden soil. 

Above, the lighter colored soil that I'm pointing to is a small handful taken from under the macnut tree. I poured it atop the garden soil, only 2 feet away, then took the photo. The garden soil is obviously darker in color, it is crumbly and full of organic material. It feels and smells like good garden soil. It feels nicely moist. The light reddish soil is gritty, dry, appears to contain no organic material. The color contrast is significant. 

I was under the impression that by not tilling or digging, but rather by using top dressing alone, one would improve their soil via the no-till method. I've seen that claim published in numerous discussions of no-till. Hhmmmmm. That doesn't appear to be the case for my type of soil. Top dressing and the use of manure teas did not enhance the appearance of the soil around the macadamia trees. 

This little observation just reinforces my belief that light tilling combined with mulch and compost applications creates better soil for me than using no-till methods being touted by the latest fad in gardening. No-till very well may work in other situations, but it surely isn't doing the trick for this farm....at least not in this stage of development. I'm sticking with my compost piles and tiller. 

Filling In After Mining Dirt

This is the most recent soil mining area, a spot that I'm turning into a parking space for the pickup truck. It's hard to tell from the photo, but the giant hole (which was 9'x16' and 2' to 3' deep) is almost filled in. Just a small spot by the white bucket still needs some rocks. Just a few more buckets of rocks and the area is ready for a topping of gravel. 

This is just one example of what I can do to put a spot back into use after mining the soil. Oh by the way....the answer is "yes". Yes, I have that many rocks on my farm that I can use as fill. I save the big and pretty rocks for stone walls, with the rest being used like this -- fill. 

Other past mined pits were used to make growing beds. Some holes were filled in as a hugelpit....woody material on the bottom, organic debris atop that, and a cap of compost, soil, and mulch. These pits make super growing beds. I currently have bananas, turmeric, sweet potatoes, and pipinolas growing in such beds. 

Another pit I've been using for organic debris that I don't deem fit for veggie growing areas. I'll layer in dog poo and kitty box tootsie rolls with grass clippings and a bit of soil. This is also how I deal with donkey and sheep manure the day after they are dewormed, so that most of the residual dewormer goes into the pit. Once the pit is mostly filled, I'll plant a tree there. (I think I've mentioned this before, but at my age, it's news to me!) It's a good way to mine soil from a smallish pit and turn it into a tree growing spot. 

To tell you the truth, I never thought I'd be mining soil until I moved to this place. Wherever I lived before, soil was a given. It was everywhere. Nothing like living on the side of an active volcano to make one appreciate real soil that you could sink a shovel into. 

Potting Soil

Recently a person quizzed me about what I'm using for potting soil to start seeds. Over the past two years I've used a number of different mediums, but currently this past couple of months it's been Pro-Mix BX. Why? Because that's what I can get a hold of locally that actually works well for me. The "working well" is the important part. 

When I first started growing seedlings I tried an assortment of homemade potting mixes...

...garden soil

...sifted compost

...volcanic cinder

...cinder & peat moss

...peat moss

...sand

Each had a drawback that didn't work well for me. I'd say that the cinder & peat moss worked best, but the cinder I had was too coarse. I needed something finer. And the pH was way off, so it only good for starting seeds. 

I could have kept experimenting but I needed to start getting serious about growing food. So I looked to commercial potting soils, something with an established track record. By shear luck I stumbled upon several bales of Pro-Mix that someone wanted to sell. I jumped at it. I was able to get a pallet of Pro-Mix MP, which is an organic version. The basic difference between BX and MP is that BX contains vermiculite and a wetting agent (MP doesn't), plus MP uses about 30% coconut coir in place of spagnum moss. MP cost significantly more than BX, and another drawback for me is that it dries out quickly. I had to water seedlings daily, even on cloudy days. When I ran out of MP I looked around and settled on Pro-Mix BX, the version that my local Ace Hardware sells. 

BX is not considered "organic", I guess because it contains a wetting agent. This doesn't bother me, because as I see it, organic gardeners use Dawn dish detergent as their wetting agent and it surely isn't organic either. I amazes me how gardeners that are so wrapped up in being organic will turn a blind eye to using Dawn, cardboard, newspaper, old carpet, regular garden hoses, plastic rain barrels, etc. All these have traces of chemical contamination and aren't organically "clean". But as I said, it doesn't bother me. Realistically, I can't totally avoid chemical contamination in my life. Not even the air I breathe is chemical free. I just try to be reasonable about things, not fanatical. 

So my current potting soil is Pro-Mix BX. 

Some day when I have the time to fiddle around, I plan to come up with a homemade version. In the end, I'd like to be more self-reliant and have my homestead provide for itself the best it can. I have access to homegrown fresh spagnum moss, though I don't know if that is something to use. I'd have to mix it with something else. I also could gather lots and lots of coconuts locally, which couod be made into coir. But I would have to figure out how to do that. I have volcanic cinder which I would need to clean, sterilize, and sift. I have compost & garden soil which would also need to be sifted and sterilized (fungal diseases abound in the tropics). And I have easy access to lava sand. It's a lot to be figured out. As I said, I don't have the time for that right now. But my gut instinct says that lava sand or volcanic cinder,  along with fine high nutrient compost might be the ticket. 

Mining Dirt

"A", who also lives on Big Island,  wrote to ask me where I get my garden soil from. Quite honestly, I don't buy it. In fact, I'm quite leery about importing soil onto my farm. Bringing in soil could be introducing serious unwanted pests, plant disease, or weeds. I've already got enough little nasties to deal with and I surely don't need more! I've heard of other people who have brought centipedes, stinging caterpillars, little fire ants, and coquis to their places via soil and plants. I accidentally brought a coqui frog  on building lumber, though hubby and I spent several minutes hunting the buggah down that evening. While I will bring in the Kona mulch, which is raging hot and nasties can't survive the heat, I won't bring in non-heated organic matter nor soil. 

So, do I just create all the soil I need? Not hardly! It takes lots of time, effort, and resources to make garden soil. I simply can't do it, at least not enough of it. So where do I get soil? I mine it on my own farm. 

The above area that was mined is about 9' x 16'. It's a spot that is destined to be a parking spot for my truck. I could have simply leveled it out some, topped it with gravel, and parked the truck. But I looked at all that decent soil that would be going to waste. What a waste. So I decided to mine it instead. Out came the pick, o-o bar, and baby sledge. Over the course of several weeks I gradually worked my way. I'd remove rocks, scoop out the soil into waiting buckets, then return the rocks. As I worked, the hole behind me got bigger and bigger as the rocks weren't enough to replace the soil volume I was removing. In spots I dug 2' down, in others 3'. I mined quite a bit of soil, which went down to the gardens. Now I'm in the process of bringing rocks to fill in the rest of the hole. It will take me another couple weeks to finish this project. ....... Yes, I'm most likely crazy. But I did get quite a lot of soil added to my garden areas. 

This sounds like terrible labor, but I don't find it to be so. I only work about a half hour at a time, so it's a nice workout. No need for an exercise gym membership here!!! No need to pay to work out on somebody else's machines. No need to go jogging for half an hour. I can find plenty of good exercise right here on my farm. 

I've moved on from this driveway parking site and am now mining soil down in the dry river bed area. Lots of soil, few rocks, and not nearly the beneficial exercise. I'm currently mining soil for the new greenhouse growing beds. 

Yes, as a real estate agent once noted, my farm has deep soil. But it's all between a lot of rocks! 

Using Hair, Fur, and Feathers

What do I use to make my compost? I get a lot of requests for my compost formula, a recipe so to speak. Well, I have no set recipe. I add whatever organic, non-toxic material that I have. Plus some things that are not organic in nature, such as lava sand, volcanic cinder, ocean water. The basic idea is to keep the material moist (but not soaking), aerated, have both nitrogen containing and non-nitrogen containing material, and to have it chopped into small pieces if possible. If the compost isn't working, then one of those factors is out of whack.

Because I get so many questions about compost and soil amendments, I've decided to post a string of articles about this subject, strictly about what I do, not how others should do it. My methods may be right, but then again, they might be wrong or just a tad screwy. I'll focus on the popular points and answer questions that I've gotten. So here it goes. 

Question received ...... "Can hair be added to a compost pile?"

Answer .... Yes. 

For years I've been throwing human hair trimmings to the gardens. So either it goes into a compost pile or it just goes right directly into the soil. I see no compelling need to subject it to the heat of composting because :

a) hubby doesn't have head lice

b) the dogs don't have fleas, other skin parasites, or infections

c) the sheep don't have lice or other skin problems

So I use hair, fur, and wool. And even feathers. 

Above......I trimmed hubby's hair the other day. Rather than throw the hair into the trash, I swept them up and added them to a garden bed that I'm working on. So although he never gets his hands dirty or even picks a ripe veggie, he's contributing to our food production. Ha. 

Human hair is just fine in the garden. I'm told that other gardeners collect hair from hair salons to use. Purists may warn and scream about chemical contamination. While there are probably small bits of various chemicals in that hair, I would venture to say it's no worse than all the pollutants that the garden is already exposed to that come along in the rain, that are in the air, that are everywhere we turn. Face it, we can never be truely chemical-free anymore. The world where I live is too contaminated. Most gardeners can only use commonsense and avoid dangerous levels of noxious chemicals. That being said, yes, I use human hair......hubby's and my own. 

What is probably more chemical free than human hair would be pet fur from one's own dogs or from pet grooming shops. Pet fur wouldn't be as subjected to dyes, conditioners, and styling agents as human hair. I personally have three dogs that are seasonal shredders, thus I get piles of fluffy fur when they shed. It all goes into the garden to one place or another. 

Above is some of Willie's fur added to the hugel bed. He's just starting to shed again. Over the next few weeks he'll donate bags of fur. 

My feather source is the birds we process for food. Chickens. Ducks. Turkeys. While some of the feathers are set aside for artist friends, most simply go into the soil. 

Is there much benefit to hair, fur, or feathers for the soil? I don't know exactly what it would be, but it's organic material going back to nature and that sounds good enough to me. In Mother Nature, animals die and their fur, feathers, or scales decompose, becoming part of the soil. Thus recycling these things would be an acceptable permaculture method. 

Hair and feathers break down slowly. So you might be able to visually identify them in the soil for months. Think of it as a slow release fertilizer. Since they are slow to decompose, I spread it out rather than leaving it in big clumps. 

With sheep wool, I take advantage of the fact that it slowly decomposes. I use it for mulching. It tends to produce a felted mat that suppresses weeds but allows rain water through. I don't have enough sheep for wool to be a big item in my garden. Afterall, I only have hair sheep, not woollies. But I'll use what I can get. 

What is Soil pH?

Jerry has asked, "What is pH? Why do you test for pH?"

For a non-chemistry major, the simplest definition for pH is to say it measures the reactive ions in a solution. It allows someone to classify a solution as acidic or basic, that is, how far off of neutral (non-reactive) it is. I'm sure that went over plenty of heads, but I don't know what else to say. But other than a definition, I'll talk about how pH affects my soil. 

Where I lived on the mainland, my soils were always slightly acidic, which most plants thrived in. Garden areas received a sprinkling of granular lime each spring or fall and it was sufficient to keep a happy veggie garden. I never really thought much about pH. 

Things are quite different where I'm now living.....and actually trying to eke out a self reliant existence. When I started out my homestead, my soil was acidic, around 5.4 to 6. Since I live down wind from an active volcano, I get a nice dose of acid rain on a fairly regular basis. Plus I get daily light deposits of acidic volcanic ash, what housekeepers call gritty dust. On top of that, soil in my area is calcium deficient, so there is no calcium buffer for this acidity.

Besides acidic rain and ash affecting my soil, I also add various soil amendments as I attempt to make my gardens more productive. These amendments have an effect in soil pH. Composts and manures tend to acidify. Coral, shells and bone tend to do the opposite.

By the way, the amount of rainfall has an effect of pH too. Lots of rain leeches out calcium, leading toward acidic soil. Since I live in a location with normally 80" of annual rain which often comes in heavy downpours, I sometimes see a problem with leeching. 

So why is pH important to me, why care? The level of the pH has a direct bearing upon which nutrients and minerals are available to the root zone -- to the soil microbes and plant roots. I could have the best combo of nutrients & minerals but they won't do any good if the can't be utilized. In soils that are overly acidic or alkaline, nutients and minerals are not available to soil organisms. 

My goal is to keep my soil pH close to 6.5 to 6.8. Most vegetables like that range. I use coral sand, burnt coral chunks that have been hammered into small pieces, plus burnt bone that has been hammered into finer pieces. And wood ash. Only the wood ash adjusts pH quickly. The others work slowly, but are very important for adding much needed calcium and other minerals. I rely upon the coral and bone as my primary pH controls, with wood ash being used for quickly (meaning 2-4 weeks) needed measures. Besides, wood ash also is a good source of potassium in addition to having some calcium and other trace elements. Wood ash is a good fit for "sandy" type soils like mine. 

I currently produce or gather all of my soil additives. But when I lived in NJ, I used pulverized and granular lime for addressing pH issues. Of course, they were purchased at a store. But old farmers would tell of times when seashells and oyster shells were used to help condition the soil. Some recalled their fathers crushing the shells under the wheels of a truck before spreading them in the fields. Others remember the shells being burnt first. When hiking around the back areas of NJ beside and through old farm fields, it was not uncommon to see seashell pieces sticking out of the ground. Here in Hawaii I don't see the abundant seashells that I saw on the beeches of New Jersey. Thus shells are not common enough here for me to make a special trip to gather them up for garden use. But if I see them, I'll add them to my collection bucket. 

pH Soil Test - Homestyle

I've been fielding numerous email questions about soil, with the number one about a home test for pH. I find that home testing is simple. And because of our acidic rain here, due to the erupting volcano, plus the fact that I add soil amendments between each crop, I test soil pH frequently. How frequent? For right now, between each crop. Once I start cutting back on soil building amendments, then I'll probably slow down to 2-3 times a year. Both the volcanic acid rain and the biomass soil additives (compost, mulch, manures) contribute to acidification of the soil. 

The test I do involves test strips and/or pH paper. For the bare minimalists out there, you could use a mixture made from red cabbage that would give you a rough acid vs base result. Or for the techie oriented gardener, there are pH probes. I have a probe but I found that it needed cleaning between use for a reasonably accurate reading....and quite frankly, I never seemed to have ultra fine sandpaper on hand when I needed it. Usually I couldn't find the sandpaper because someone used it (sigh...usually me)......that is, IF I could find where I last misplaced the pH probe! I've done that plenty of times. In fact, right now I havent the foggiest idea where the dang thing is. For some reason that's beyond me, I always keep the pH testing strips & paper in my medical kit. Thus I can always find them. Yeah, I equate test strips with medical testing, thus the reason I find them in my veterinary supplies. Hey, I do what works, regardless of how silly it seems to others.

So for my home tests I need...

...pH test strips or paper. I buy them online. 

...distilled water. 

...soil sample. 

...Test strips & paper. While not the most accurate testing equipment, they are plenty accurate enough for gardening. I just need a general idea what the pH is. 

...Why distilled water? Because my catchment water comes from acidic rain. I adjust the pH of the catchment water using baking soda once a month, so on any particular day heaven only knows what the water pH actually is. By using the same gallon bottle of distilled water over a stretch of time, my test results at least are relative to each other. This gives me a better idea of the trends going on in my gardening and soil amendment efforts. 

...The sample. Getting a soil sample is simple as long as I follow a few rules. Clear off the top couple inches of soil which is primarily mulch. This upper section is not where the plants roots are. I'm targeting the plant root zone. Once I'm down to the root area, I'll simply take a scoopful and put it into a clean cup or jar. 

Next I'll add water, enough to cover the soil with the intent of having a layer of water atop the soil once the soil particles settle out. I don't have a centrifuge, so I need to either rely upon gravity to settle the soil particles or drip the soil slurry through a coffee filter.  I've often toyed with the idea of making a bicycle tire centrifuge, but haven't gotten around to it yet. If I actually had a bicycle, it would be simple, but alas I don't have one.  Maybe I could just put the soil/water mixture jar in a sling and swing it around my head for a bit. But I haven't tried that yet either. So I use the lazy gravity method by letting it drip through a piece of napkin, paper towel, coffee filter, or scrap of cloth in order to clarify the water. The only reason I want the water to clear is so that the soil particles don't interfere with my being able to see the color on the test strip/paper. Without filtering or settling out the silt in some fashion, the muddiness interferes with the color on the test strip/paper. 

(I normally don't use a coffee filter, because I'm a scrooge and filters cost money.)

Once I see some reasonably clear water, I'll dip my test strip into it and read the results. I could use an eyedropper, pipette, or even a spoon the collect that water and use it to wet the test strip/ paper. Just alternative options, but I usually just make a quick dip. 

Reading the test strip or paper is simple because they come with a color chart. Just match up the colors then read the chart. Bingo. 

I used to use a swimming pool test kit, but I found a problem..........

....As the above test shows, my soils' pH is often BELOW the test strips capability. On the above strip, the pH is the second colored square down. This test produced a barely yellowish result because the pH is actually below 6.4. How much below I couldn't tell. Thus this test kit won't do for my soils. 

Since I didn't know how much lower the pH was, I decided to use a more broad range pH test that I had on hand. I needed to know if this soil was still in the 6 range, or if it had slipped into the 5's or worse. So here's the next result......

The chart indicated that the pH is 6-ish. The color was strong enough to tell me that it wasn't slipping down in the 5 range. 

But for my routine testing, I don't use either of the above kits. While these two each have their place, I strongly prefer using these.......

............strips:

............paper:

The strips and paper seem to give me consistent results and are within the range most useful to me. So I took a strip and tested my sample. In the photo below, it's the strip on the left. The results indicate this soil sample is at 6.1. ......... It was the clear amber but a trace of color change was taking place but not strongly enough to darken the entire color patch to make it 6.2. But as I've said, I don't need a real accurate result, so to say the soil is 6.0 to 6.2 range is accurate enough. 

The strip on the right is another soil sample from a different garden bed. You can see that there was a stronger color change. This bed has been consistently testing at 6.4-ish. 

For garden beds that I have been using for a while, I tend to use the pH paper. I find that it's quick and simple to use, plus it's cheap. I can get a lot of tests out of a roll. The down side is that the roll can get ruined easily if I'm not careful. Dropping it into a puddle is not advisable. And forgetting to put it back into my pocket, thus leaving it outside to be rained on is also not a good idea. 

(Above-  I tear off a short strip of paper off the roll, about 1 1/2 to 2 inches.) 

The above test indicates a pH around the 6.0 and 6.2 range. **** Important----- notice that I hold the paper so that gravity lets it hang down vertically. Once the paper gets wet it is very limp. With people who are having problems using pH paper, it is often because they try to hold the paper upright or horizontal, rather than letting it hang. 

Once I know the current pH status, I can guess-imate how much coral sand, crushed bone, and wood ash to till in. It's only a guess, a gut feeling acquired from months/years of doing this. The soil that tested around 6.0 will get a heavier sprinkling of wood ash than the one that tested at 6.4. Both will get a dusting of coral sand and a moderate addition of bone. That's along with two inches of compost and a light layer of rabbit manure. 

Soil Sediment Test Interpretation

Soil sediment -now what......

Ok, now that I told you how I do a basic rough soil sediment test, what do I do with the results? 

First of all, this home test just gives a basic rough idea, it doesn't examine the soil particles under a microscope, so I don't know exactly what my soil looks like. But I don't see the need to be that precise. Nothing is all that precise in my gardening anyway. And besides, I'm not an obsessive-compulsive.

Why forego a more precise laboratory test? Foremost, the plants seem to be growing ok. I'm not seeing significant "sick" soil anymore. And since much of my homesteading approach keeps the idea of frugality in mind, why spend the money if I don't have to. 

People often ask me what type of soil I have. Before I learned about soil sediment testing, I had no idea. I was aware that some areas on the farm drained well, some got mucky after a rain, others didn't drain, and yet some soils wouldn't even accept rainwater (hydrophobic soil). I started looking into some beginners soil science and discovered basic soil components......sand, silt, clay, organic material. Im no soil genius. I'm still learning about soil. But I have been introduced to the soil triangle, which I'll try to explain.  

The triangle charts, below, help me interpret my test results. Using a soil triangle chart, I was able to figure out what kinds of soil structures I was dealing with and it gave me a foundation to work from for amending my soil where needed. Here what the triangle chart looks like, you can find all sorts of variations on the web........

So how to use this chart? 

1-  Lets say my soil sediment test showed me that I had 60% sand. So I'll circle the number 60 on the bottom of the triangle. You can see two tan lines going up into the triangle to the left and to the right of the number 60. I will use a marking pen and draw over those two lines, going from the number 60 out to the sides of the triangle, 

2-Now, lets say the soil test showed that I had 30% silt. Now I look for the number 30 on the right side of the triangle, the one labelled "percent SILT". There are two tan lines eminating from the number 30, one horizontal and one going down to the left. Using the marking pen, I will highlight those two lines, again out t the triangle sides. 

3- The last soil component is clay, and my test says 10%. So I circle the number 10 on the left hand side iof the triangle, the side that says "percent CLAY". Using the the marking pen, I will highlight the tan lines  running from the number 10, one going horizontal and one going down to the right.

4- Now I will look to see where all three highlighted lines intersect. In this case of 60% sand, 30% silt, and 10% clay, the lines intersect in the "sandy loam" zone. So that's what my soil would be classified as. 

This next soil triangle has a shaded area which notes the more preferred soil types for veggie gardens, while the yellow area is less desirable. 

This photo was provided by a person explaining how to use the triangle. Regretfully I don't know his real name in order to give him credit for the picture, 

In the actual test I did the other day, my soil sample values were.....

     73% sand

     16% silt

     11% clay

By using the triangle that puts this sample in the "loamy sand" category. But it also shows that the soil composition is outside of the grey "preferred" area. So this garden bed still needs some work. In actual day-to-day use, this bed is productive, but only because I've been working with it. Veggies grow fine but only if I watch the moisture level carefully. The soil drains very readily and dries out quickly. Between crops I will continue to add amendments : compost, manures, biochar, and till in old mulch. Since this garden bed started out as 95% sand, 5% silt, and unmeasurable amount of clay, it's structure is improving. When I started out growing in this soil, the plants were small, starved for moisture and nutrients, and their roots too warm. I had started with beans and they were a pathetic lot. But now beans growing in this soil look good and yield well. 

I've been asked a few times.....why bother with the testing. Why not simply dig in a lot of compost. Well, that's one way to try doing it. But my soil structure varies from location to location. Some areas are very gritty and sandy, while others are mucky. Thus I don't think the approach of one-size-fits-all would give the best overall success. By doing this simple test, I can learn what soil components a particular garden bed needs. By amending the soil, I can come up with a bed that retains moisture at an optimum level while still draining, and holds nutrients so that they don't rapidly leech away. Excessive clay is not one of my problems, I learned via these tests. 

Soil Sediment Home Test

Sediment or tilth test. Why? So that I can evaluate the effect of my garden amendments, Since soil structure has a bearing upon soil moisture & nutrient retention, I am aiming for soil that is desirable for the type of plants I am growing. 

Home test, why? I could always just send a soil sample off to a lab, but why? I don't need super accuracy, nor do I need to give my hard earned cash to a lab several times a year. A low tech home test is just fine for my purposes. Besides, I test each garden bed at least once a year, so that's a lot of tests. 

What I need.....sool sample, straight sided, flat bottomed clear jar, ruler, dish soap, calculator if I'm not up to snuff about using my brain to do the math that day.

Collect sample

First, choose a representative soil sample. Should be from the plant root zone. Since my garden soil is mixed well the top six inches but often has a mulch cover, I will scrap away the mulch and the top 2-3 inches of dirt, then take my soil sample. 

Amount.....enough to full my jar by 1/3. I'll spread the soil sample out onto a flat plate or tray to dry. Once dry, I'll crush and soil clumps and put the soil through a sieve or colinder. I want to remove any pebbles, roots, etc. 

Next I'll put the soil into my large jar. As I said, I'll fill the jar 1/3 of the way. Then if I have it on hand I'll add a heaping teaspoon of dry automatic dishwasher soap. This helps get the soil particles wet and separated, but with my soil type I haven't found it to make much difference. Now I'll fill the jar with water within an inch or so of the top, put the lid in tight, and give it a good shake to get all the soil wet and suspended. I'll take care to make sure nothing is left stuck to the bottom or sides. Then the jar gets set on a flat surface so that things can settle. 

Layers will now develop. Coarse sand settles first and within the first minute. At no more than two minutes I use a marker to note the top of this sand layer. 

The sandy layer will look coarser than the silt and clay layers. 

Silt is the next layer to settle out. This will take about an hour to form. It will be a different colored layer. Most people say that their silt layer is darker than the sand layer, but here my sand comes from dark lavas, so my sand layer is darkly colored. At one hour I will mark the line of the top of the silt layer. 

Clay is the slowest of the soil particles to settle out. Heavy clay layer will settle out in a day, finer clay in two days. Some people say to allow clay to settle for a week but I haven't found that to make a significant difference on my home tests. I suppose it matters if ones soil had lots of fine clay, but mine doesn't. 

I use a tongue depressor to mark my layers, but you don't have to. I just happen to have thousands of the little buggahs in hand, so they are handy. I will then measure the depth of sand, silt, and clay, as well as the total soil depth in the jar. These measurements are used to calculate the percentage of each soil component.

For example, the jar above shows 2 1/4 (2.25) inches of sand, 1/2 (0.5) inch of silt, and 1/3 (0.33) inches of clay, for a total of --------3.08 inches. Divide each particle depth by the total soil depth to get the percentages:

2.25 divided by 3.08 = 0.73 or 73% sand 

0.5 divided by 3.08 = 0.16 or 16% silt

0.33 divided by 3.08 = 0.107 or 11% clay. (I rounded to the nearest whole number)

Sifting Soil

Normally I'm not a soil sifter. I just pick out rocks that are large enough to interfere with the rototiller. But one of the community garden workers really got into digging one of the beds  rather deeply. So I seized the opportunity to make that bed into something special.

Carrots, parsnips, and daikon don't take kindly to rocks. When the tap root hits a rock, I've seen some pretty weird results. Roots that bend 90 degrees. Double or triple forked roots. Some that simply don't form edible roots beyond the offending rock. What these veggies like is rock, or even pebble, free soil. Well I acknowledge that I'm not going to have an ideal bed for these root crops, but I can have a reasonably good area for them. So I decided to sift out rocks. 

Doug used a mattock to get down a good 10-12 inches. And he removed all the big rocks larger than a baseball. That's a good start. He got all the heavy work done. Now I followed behind, sifting the soil and refilling the bed. 

I wasn't sure what to use as a sifter. I considered drilling one inch holes in the bottom of a bucket or dish pan, but I didn't have a suitable bucket/pan on hand. I thought about nailing four pieces of short 2x4s together then stapling a piece of wire mesh to it, making a sifter. But the only sizes of wire mesh I had handy was either too small at 1/2" or too large at 2"x4". Humph. Then my eyes landed upon a greenhouse tray. So I gave it a try. Worked like a charm. A tad flimsy, but it did the job rather easily. 

I sifted right atop the bed and soil pile, letting any pebbles naturally roll down to the bottom of the bed. These I could periodically scoop out. I was surprised how easy this was. 

Once the bed is completed, I think the garden workers will opt to grow carrots first, but it's their choice. We shall see. 

Sifting Garden Soil

First if all, let it be known that I don't sift my garden soil except for the carrot bed. I have my reasons. Read on.

This week I read an article instructing new gardeners how to start a garden bed. One of the steps included sifting the soil through a 1/2 piece of hardware cloth. I not only find that not to be necessary, I find it to be detrimental. By sifting, one removes all small stones and cinder larger than 1/2 inch, chunks of organic material, half rotted leaves and grasses, decaying roots and rootlets. All the things being removed are important soil components, in my opinion. 

Rocks to the left. Organic debris on the right. I leave it all in place. 

Small rocks & cinder:

          I keep anything smaller than a hen's egg. Bigger pieces interfere with the rototiller. But rocks and cinder help with drainage, help maintain soil structure, and are a source of minerals for plants, microbes, and other soil denizens. It makes no sense to me to remove small rocks via sifting then later add rock dust for minerals and cinders for drainage. Hey, it was already there before you removed it! The soils of England are a prime example of the adverse effects of rock removal. For decades small children were rewarded for removing stones from the fields. Those soils now suffer the effects ....compacting, clumping, draining poorly, lacking mineral fertility. 

Organic material (rootlets, leaves, twigs, etc):

         Sifting the organic material out, then turning around and adding compost sounds like a waste of good time and effort. Why not just leave the decomposing material right there in the soil in the first place? The microbes that specialize in breaking that stuff down are already in place and doing their job. Besides, the chunky stuff helps retain moisture while at the same time promoting drainage. 

The only place where I sift soil is the bed dedicated to carrots. Reason? Rocks cause the roots to split and grow weird. I find that this sifted soil is more difficult to maintain. It drains poorly. It tends to become hydrophobic if it dries out. Worms don't like it. It compacts readily. 

My suggestion -----  skip the sifting. Just pick out the big pieces if they get in the way. 

Grow boxes - Making Soil

It's time to empty out some of my grow boxes and start them over again. Below is a picture of one box that I've opened and removed a couple buckets of soil out of it already. First of all, you can see that the surface of the soil has gone down a bit more than a foot from the top edge. Initially I overfilled the box by about 3 inches. So over the course of 6 months, the soil has settled quite a bit via decomposition of the organic material (grass clippings, weeds, compost, horse manure, and chicken litter).  I had expected that but I didn't know exactly how far it would go down. 

Next, I was impressed by the well developed root system the sweet potatoes made deep down into the box. The roots travelled all the way to the bottom although the tubers were in the upper 12 inches. 

I've opened this grow box and am taking some of the soil out to use in filling another grow box.
 You can see the deep root system that the plants made. 

When I loaded this box in the beginning, I placed the coarsest material on the bottom. The only pieces still intact were the bamboo chunks and 1 inch thick tree branches. Everything else had disintegrated or else was soft enough to crumble by hand as I unloaded the box.

Most of the organic material has decomposed, turning
into a medium brown soil. 

Most of the material I had originally put into this box is no longer identifiable. It is all crumbly and medium brown in color. As a bonus, I found a few dozen worms living in it. 

I emptied the box, returning to coarse stuff to the bottom. Then I refilled it with lasagna style, with thin alternating layers of  organic material (grass clippings, chicken pen litter, horse manure, weeds, waste mangos) and dirt which I took out of this box. I used 1/3 of the dirt for refilling the box. The rest of the dirt went to starting two new grow boxes. 

Myth : Tropical Soil is Fertile

When I moved here I had plenty of people tell me that everything would grow great here. Lush. Tropical soils were fertile. I was actually believing this until I tried growing flowers and veggies. Yes, I had been sucked in by the myth of fertile tropical soils. I thought gardening would be easy and take care of itself! 

Grasses grow great on my farm. Ohia, eucalyptus, and guava trees thrive. Things are always green. But when I started growing flowers and veggies I learned something very significant. Those grasses and trees don't need very fertile or moist soil.

My mother's grass. It was mowed too short when it was first started.
Now it never grows thick nor tall. I could improve this but she is not
interested in having to mow the grass more than once a month. 

The fertility of soil on my farm crashes as soon as the sun can reach the soil surface. So wherever I mow the grass short, the soil dries out, the sun kills the micro-organisms, the grass growth is stunted. Whenever I tilled or flipped over the soil, things didn't want to grow well in that spot. Thus the soil itself appears to have rather poor fertility, with it's fertility highly dependent upon the ecology of surface micro-organisms and surface moisture. A thick grass mat keeps the soil surface shaded and moist. Remove that, and the soil's toast.

In my first few years of gardening, I really crashed the soil ecology. In order to get harvestable vegetables, I needed to rely on commercial fertilizer. I knew that I needed to change my gardening methods, but I was so busy clearing land, building the house, and caring for my parents that I resorted to commercial methods for the quick fix. That meant lots of irrigation, fertilizer, herbacides, pesticides, fungicides.

Now after many seasons of adding compost, manures, trace minerals, inoculated biochar, and constant mulches, my soil is producing great veggies. So many people look at the garden and think, "Tropical soil is so fertile!" The same exact thing happens when people look at the community garden here. I always hear, "Well of course, you're starting out with good tropical soil." FALSE! These gardens are thriving because of the work that has gone into improving soil fertility. It didn't happen by chance.

I'm still experimenting and learning about how to handle the soil on my farms and at the community garden to make them fertile. Some tricks that I find work:
...keep the soil surface covered with mulch.
...if I don't have enough mulch, then let the weeds grow and shade the soil surface. This is a better alternative than letting the sun bake the soil surface.
...add compost with each new crop being planted. Plus till in the old mulch.
...use inoculated biochar in the compost, rather than plain dry biochar. I use urine, manure tea, or compost tea to inoculate the biochar.
...use manures in the compost.
...never let the soil bake dry.
...use a little ocean water in the compost for trace minerals. Or use fermented fish waste when I have it.

As I said, I'm still experimenting. I've been using ocean coral, burnt animal bones, and wood ashes. I'm switching to low-till in the improved areas so that the soil surface is only disturbed in a narrow bed where the seeds will be sowed. I'd like to install drip irrigation, but that will have to wait for now.

Ah, so much to learn, so many experiments to try!