When to Amend Garden Soil and When Not to.
The two types of garden soil that really need to be amended the most are clay soil and sandy soil. Clay needs to be amended to loosen it up. The roots of plants need to have the ability to transfer oxygen through the soil to the root system. That’s why plants do so well in loose soil.
The best way to amend clay is to work into the soil as much organic matter as possible. Rotted leaves, rotted grass clippings etc. Ideally, if you have this material in a compost bin giving it a chance to break down before adding it to the soil that would be perfect, but not necessary.
Wood chips should only be added to soil after they’ve been sitting for at least 3 years, giving them a chance to break down before adding them to your soil. Fresh wood chips need a lot of nitrogen to decompose, and if in your garden they will pull that nitrogen from your existing soil, depriving your plants of the nitrogen that they need.
The more organic matter you add to your soil, the happier your plants are going to be.
Do not remove soil from your beds before you start amending the soil. Doing so will create a “bathtub” where water can get into the bed, but will not be able to drain out. Not good for plants! Plants do not like “wet feet”. Just put the organic matter on top of the soil and mix it in by hand or with a rototiller.
If you have really sandy or gravel based soil in your yard it’s a good idea to amend with organic matter just to add extra nutrition to your soil. Most plants actually love sandy or gravel soils, so when you add organic matter to these soil to take a good soil to a superior soil that plants will thrive in.
The rest of this discussion started out as a post on my private website for backyard growers and their potting soil mixes. This is what I wrote . . .
There are a lot of people that are sure to tell me that I’m doing it all wrong because . . . I’ve never tested my potting soil. All of the plants that I grew and will grow this year in that soil did great! Those that didn’t? I figured they were just too wet which happens a lot with potting mixes. Potting mixes need to drain well so the plant roots can breath.
Some people have really poor soil in their yards.
One thing that I try and remind myself of is that really, really good soil is topsoil that contains a lot of organic matter that wasn’t put there by anybody but Mother Nature. Topsoil is nothing but rotted organic matter that has rotted so well that it turned into really, really rich soil.
So when making a potting mix, I try and mimic that. Lots of rooted organic matter, then enough loose material to makes sure the roots can breath and the water can run through.
PH? Not sure what the PH is. Never tested for it, never had a big enough of a problem to be concerned about it.
Now, with all of that said, if I were to decide to grow nothing but Rhododendrons, tens of thousands of them for the wholesale trade, container grown, I’d probably have the soil tested to make it as perfect as possible. But since my nursery is nothing but a big batch of mixed dogs, no point trying to make any one particular plant happy. I just make generic soil that makes everything happy.
Years ago I planted 705 Rhododendron in the field. 600 at my friend Larry’s house, soil wasn’t bad, but a little sticky. It was clay soil, but not ugly, ugly clay soil. Great for Forsythia and dogwood trees, but the Rhody’s grew slow. They didn’t look bad, they just grew a little slow.
The other 105 wouldn’t fit in Larry’s yard so we planted them down the road from my house on land owned by a mutual friend. Some sand, mostly gravel, lots of big rocks! I mean digging a hole you could see sparks coming off the spade. Those kinds of rocks.
We didn’t amend the soil, we just planted the 105 Rhododendron. No water on the property and the soil drained like kitchen colander. It was dry. That batch of 105 Rhododendrons thought they were planted in heaven! They grew like weeds! We sold that batch two and three years ahead of the ones in the sticky soil. They loved that rock farm.
The lesson? The magic wasn’t in PH or soil amendments. Rhododendron hate wet feet more than anything in the world. All we did, (by accident!) to make them happy was to give them nice dry feet.
No rocket science, just common sense from the perspective of the plants. We can read 100 books, but until you experience a few accidental tests like that you really don’t get that it’s really about what the plants want, not what the book says, or what the professor says.
The professor? He’s never risked his grocery money on a thousand plants in hopes of paying a few bills. His bills are paid. He’s a professor. He doesn’t take chances. He’s really smart, he doesn’t need to gamble. He’s wired to take the sure bet and get a pay check every week. The rest of us? We’re in it for the game and the chance of the bigger reward.
Nothin against higher education. It’s just not my cup of tea. But the true irony is when I get an Email from a horticulture professor asking permission to use my backyard growing system in the classroom. It’s happened more than once. That’s all the compliment that I need. My hat is off to the scholarly type that realizes knuckleheads like me actually have real world experience that they can blend with all of that book learnin.
On many occasions people with horticultural degrees have purchased my products because they realized that after graduation college they still didn’t have all the pieces of the puzzle.
You know me, keep it simple. Simple works pretty good unless your putting human beings in a rocket ship and sending them off to another planet. For that, you need to be a lot smarter than me.
Stay inspired! -Mike McGroarty (Who is this Mike McGroarty Guy anyway?)