Pesticide Side Effects - An Insecticide Is Not Just An Insecticide

There are many pesticide side effects, but an important one that a lot of people don't know about is the effect of pesticides on non-target organisms.


Sustainable Fertilizer - Should We Be Using Our Lime Deposits?

Is Lime Sustainable Fertilizer?

Mining limestone is big business, but does it give us a sustainable fertilizer?

The world's biggest limestone quarry is right near the top of the state of Michigan on Lake Huron. It's 7000 acres, roughly half the size of Manhattan.

I'm not sure how much of the material from this particular quarry goes toward agriculture, but lime is one of the most important fertilizers in organic gardening.


Photosynthesis Simple Explanation For Gardeners

This photosynthesis simple explanation is good for gardeners to understand, just so we know the very basics of how a plant eats and what we can do to help.


Home Soil Test Kits - Are They Worth Your Time?

Garden centers occasionally sell home soil test kits, but are they accurate or are you better off sending your soil test sample to a soil lab?


Today I Define Humus And Why It Rocks My Pants Off

Define humus: The organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms.

That's according to Google and it's basically accurate, although if we're getting nit-picky:

  • Humus isn't the only "organic component of soil"
  • It's not just leaves and plant material (it's anything that was once living)
  • Insects and animals are involved in this decomposition process, too.


Biological Transmutation - Can Organisms Really Transmute Elements?

Biological transmutation is when organisms combine elements together to produce new elements. As to whether or not this is actually possible, that's up for debate.


The Number 1 Problem With Organic Pest Control

I know people come searching here for organic pest control methods, and I occasionally mention a few specific techniques, but mostly I talk about a far more important concept that pretty much gets rid of pests altogether.


Vegetable Garden - 5 Tips For Growing The Healthiest Vegetables

Before I studied organic gardening, I had hardly considered growing food. Now, the vegetable garden is my main focus.

Vegetable Garden

This page is my main hub for introducing you to some important concepts on how to grow organic, so be sure to bookmark it.

The cool thing I've learned is that a vegetable garden doesn't have to be a weedy rectangle with straight rows and wide paths in the back corner of your property.


5 Vital Organic Gardening Topics Bloggers Will Still Ignore In 2013

Organic Gardening Topics

I don't read very many organic gardening blogs. I find I pick up more useful gardening tips from reading organic farming research and organic gardening books.

Most blogs just seem to be covering gardening topics that I'm not really interested in, which is fine - I tend to lean slightly towards the ecological side of gardening rather than the aesthetic side, and to advanced soil building and food growing techniques rather than the basics.


Rain Harvesting Into The Soil Instead Of Your Tiny Rainwater Barrel

I love rain harvesting.

My rainwater barrel is super cool and a good metaphor for water conservation. But I find it interesting to actually run the math and see how little water they hold, and I wonder if they are taking the limelight away from more important organic gardening practices.

Rainwater Barrel Mathematics 101

If your roof is 1000 square feet (100 square meters) and you get 1 inch of rain on a spring Friday afternoon (don’t worry, it had to get it out of its system before the sunny, warm weekend ahead), you will have 625 gallons of water coming off that roof.

I don’t know about where you live, but where I live, 1 inch of rain is common.

Let’s say you are rain harvesting into a 60 gallon rainwater barrel that will get nice and full and you can use it when organic gardening to water your tomatoes another day. But 90% of that water is going elsewhere, maybe into your city’s sewer system. Your barrel can only take 1/10 inch of rain from that 1000 square foot roof.

So while I like the 60 gallon rainwater barrel, I think there are better solutions.

Rain Harvesting Into Cisterns

A 600 gallon rainwater cistern could handle almost a full inch and a 1500 gallon cistern could easily take 2 inches. Think of it as a giant rainwater barrel. I think every house should have one of these, the size dependant on the amount of rainfall in your area.

They can be a bit tricky to fit into the landscape and some people think they are an eyesore, but they can be cleverly hidden or even buried.

Rain Harvesting Into Ponds

A more attractive organic gardening solution for rain harvesting would be to build a small pond to catch the water. A pond the size of a king size bed and 2 feet deep would hold your inch of water and if constructed thoughtfully, would provide drinking water for insects and animals.

Rainwater barrel
This awesome pond holds way more water than a rainwater barrel

Every organic garden should have some open water in it for this purpose. Mosquitoes aren’t a problem if you keep the water moving and put some effective microorganisms in it, but that’s for another article.

While your rain harvesting into a pond, you might as well bring your greywater into it to be cleaned and used as well, rather than piping it to the sewer or septic system. Your sink, shower and laundry water can all be put to use in the garden. Make sure to use non-toxic soaps, shampoos and detergents.

Rain Harvesting Into Soil

What I think we should mostly be focusing on is the soil in our organic gardens. The soil is the best way to hold onto water and makes rain harvesting into a rainwater barrel look like child’s play (not that there’s anything wrong with child’s play).

Let's look at how it works using 1 inch of rain as an example. If your roof is 1000 square feet (100 square metres) and you get 1 inch of rain, you will have 625 gallons of water coming off that roof.

A loamy sand, which is 70-85% sand (hence not very good at holding water), can hold 1.1 to 1.2 inches of “plant available water” (plant available water refers to the water that can actually be taken up by plant and microbes and also lost to evaporation; the soil can hold more water than that, but some of it is so tightly held by the soil that it can’t be used).

This loamy sand will already be fairly saturated from our 1 inch rain, though, so it won’t take much of the water from the roof.

A silt loam, which is 75-90% silt, is great at rain harvesting as it can hold the most “plant available water” at 2 to 2.5 inches. It can handle all of the 1 inch rain if you can spread the roof runoff over 1000 square feet. That might be possible with some smart engineering.

A clay soil, which has at least 55% clay, actually holds less plant available water than the silt loam because while it can hold more water, it is held so tightly that plants and microbes can’t get it. It holds 1.2 to 1.5 inches of water, again not much of our roof runoff.

So what to do?

Organic Matter: The Magic Ingredient

There is one thing that we can put in and on our soil that will hold the extra water, and that is organic matter. Organic matter is a rain harvesting genius. I don’t know exactly how much water organic matter can hold, but an article on the USDA website says it can hold 10 to 1000 times more water and nutrients than the same amount of soil minerals.

Even if organic matter holds only 4 times its weight in water, you can hold nearly an extra inch of water if you can increase the organic matter content of your soil by 1.5%, easily doable.

Rain Harvesting
Rain harvesting into the soil is the best option

A study in the Journal of Soil and Water Conservation found that regardless of the type of soil (sandy loam, clay, etc.), “as organic matter increased from 1 to 3%, the available water capacity approximately doubled. When organic matter content increased to 4%, it then accounted for more than 60% of total.”

That means we can now be rain harvesting 2 or 3 inches of rain from the roof, 20-30 times more than your rainwater barrel. This is what organic gardening is all about.

Organic matter can be brought in via compost or mulch. Incorporating 2 inches of good compost into the top 12” of a new garden bed will easily increase the organic matter content by 2-3% (although you might as well go for 6 inches of compost while you’re doing it).

Mulch goes on top of the soil, but it too holds a lot of water.

Now all that’s left is to direct the runoff to your gardens with gutters, and perhaps slight grading of the ground and swales and berms.

Rain Harvesting Summary

The rainwater barrels are a nice idea, but they don’t go very far in rain harvesting from the roof. Cisterns and ponds can hold more and should be used, but the winner in this event is the soil and especially organic matter.

Most soils are low in organic matter and if that’s the case for yours, bringing in lots of compost and mulch will transform your soil into the ultimate storage tank.

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