I started thinking about garden soil recently when a friend complained to me about her gardener.
She’d just had a large bundle of bare root roses delivered. So she asked her gardener to plant them immediately.
But the gardener spent hours picking bits of old builder’s rubble and stones out of the border, while my friend worried that the roses would die. ‘I just wanted her to get on and plant them,’ said my friend. ‘There wasn’t time to fiddle about, but she always does what she wants to do, not what I ask her to do.’
In fact, the gardener was absolutely right. The bare root roses are dormant over the winter. It’s ideal to plant them as soon as possible, but a knowledgeable gardener will ‘heel them in’ or roughly place them in the earth or in some potting compost. They’ll be fine – for weeks if necessary.
But if you plant trees, shrubs or roses without sorting out your garden soil, then much of the money you spent on the plants will be wasted.
They won’t all die. But you won’t get that gorgeous, luscious effect you see in photographs. You’ll get straggly plants with scrappy foliage and fewer flowers than you’d like.
Which garden soil is best?
You don’t need the ‘best’ garden soil. You just need to make your own garden soil as healthy as it can be.
Good soil is alive with life. There are more living organisms in a teaspoon of good garden soil than there are human beings living on the earth. They includes worms, insects, microbes and funghi.
Insecticides and fungicides can kill these living organisms off. Covering it in concrete, stone, artificial grass or anything that doesn’t breathe suppresses the life underneath.
It’s even worse if people use products like bleach for killing weeds, because it will kill the good organisms – the ones your plants need – as well as the weeds.
So when you see those internet ‘hacks’ suggesting you pour bleach on your soil as a homemade weeding remedy, scroll on by. If you accidentally spill some bleach as a one-off, don’t worry too much. The soil will recover.
If you just carry on planting plants, but you don’t feed the soil with mulch, manure or soil improvers, you’ll use up many of the soil’s nutrients. And if you never put any nutrients back, then your soil can run out. In agriculture, this is a very serious issue. That’s how vast swathes of land can turn barren, unable to grow the food we need to survive.
Can you make good garden soil?
You can improve your garden soil.
Firstly, if it’s got lots of rocks or builders’ rubble in it, pick them out.
If you have a new-build house, there’s every chance that stuff will have been dumped in the garden. It’ll be rolled flat, covered in topsoil and a layer of lawn will be added. That’s why many plants and lawns don’t thrive for long in new build gardens.
You can feed the soil by adding a layer of garden compost, well rotted manure, leaf mould, lawn clippings or spent mushroom compost. You don’t need to dig it in – I practice no dig for flower borders. Just leave the layer on top.
And while it’s better to do it in spring or autumn, you can do it any time.
Some gardeners add a very thick layer. You can read about Frances Moskovits’ amazing herbaceous border here, because she uses up to 2ft of compost. But most gardeners only add around 2″-3″.
Just looking at the people I’ve interviewed on the blog, I think you can say that if you want lots of flowers and veg, use lots of compost or manure every year. But if your garden is mainly green, with relatively few flowers, then once every two years is probably fine.
Do fertilisers improve your garden soil?
No, they don’t. Composts and manures feed the soil. Fertilisers feed the plant.
Fertilisers are specific chemical or home-made solutions or granules administered to individual plants to help them grow better. Once they’ve been used up, that’s it. You have to reapply them to get more benefit.
Soil improvers help the soil function better. They don’t get washed away or used up. They feed the soil, not the plant.
If you use fertilisers, you should get more flowers or better crops, but it won’t make a long term difference to the soil. They only benefit the plant you directly fertilise, rather than the whole garden. You also need to add fertilisers when the plant needs them or they can be washed away by rain.
If you feed the soil, the whole infrastructure improves. You’ll get better water retention or drainage, and more of the micro-organisms that keep your plants health.
Biochar is an old farming technology rediscovered for gardens
There is a new product around which can almost be described as a mix between fertiliser and compost. It’s called biochar, and was used by the ancient Amazonians to convert barren soil into fertile land.
Biochar is charcoal which is mixed with other elements, such as manure or other organic fertilisers, and added to the soil.
The original biochar was a mix of charcoal, pottery shards and manure, used by ancient indigenous tribes in the Amazon. They added it to the soil so that they could grow plants in previously infertile soil. And that soil stayed fertile for thousands of years.
I was sent some samples of Carbon Gold’s Biochar range free for review. It’s an range of organic, peat-free soil improvers, fertilisers and composts, all with biochar added.
How biochar works
Microscopic pockets in the charcoal structure of biochar hold water, like tiny sponges. So instead of all the water running away in sandy soil, it’s retained in the soil. But because it’s in the pockets of the biochar, not the soil, then clay soil is less likely to be a soggy mess.
And the water is retained in the pockets until there’s dry weather, when it’s released into the soil for the plants to use.
So you need to water your plants less, because you’re losing less water to runoff. And the soil stays moist for longer.
Microbial activity improves around biochar, too. The same honeycomb structure creates pockets for microbes and nutrients. The plants can draw on these. When plants have a steady supply of water and nutrients, they grow better and are more resistant to drought and disease.
Plants need three things to grow – water, nutrition and microbial activity in the soil. They create the nutrition from sunlight and elements in the soil.
An environmentally friendly manufacturing process
Charcoal is wood burned with minimal oxygen. That process permanently locks carbon in, so the manufacture of biochar is a ‘carbon negative’ process.
Biochar is one of the elements in the Carbon Gold peat-free compost. Most gardeners today are looking for peat-free compost, because mining peat releases a great deal of carbon dioxide into the atmosphere and destroys some of the world’s most biodiverse habitats.
But many of the alternatives have an environmental cost, too. Coir, for example, is a by-product of the coconut industry, so needs to be shipped from countries which grow coconuts. There is coir in Carbon Gold and other commercial peat-free products, although Dalefoot Composts are made from English bracken and wool.
And most peat-free alternatives are currently more expensive than the peat based ones. Although it’s hard to compare like with like, because Carbon Gold can’t be equated with standard composts, it is certainly more expensive. But it’s worth remembering that there should be some permanent improvement to the soil.
What I thought of the Carbon Gold Biochar range
I think it’s difficult for an individual to make comparisons between brands of compost and soil improvers.
We’re not institutions with rows of identical tester seed trays and laboratory conditions, monitored by trained horticulturalists.
We’re ordinary gardeners, with draughty potting sheds and imperfect ways of doing things. One successful sowing of seeds is no guarantee of anything.
I haven’t used peat in the garden for around five years. So I’ve got completely used to peat-free composts and have always found them just as good as the peat-based ones. Melcourt Sylvagrow and Dalefoot Composts are both good. And I’ve personally had good results with Westland’s New Horizon peat free compost, too.
But I thought Carbon Gold’s Biochar was a good product. I researched some of the science around it and liked what I found. It was easy to use and the plants have done well. It is expensive, but there’s a serious long term benefit to consider.
Your garden soil is so, so important. If you’re going spend time and money on any part of your garden, put improving your soil at the top of the list.
But I’d like more explanation
I found the Carbon Gold website quite confusing. You can click on ‘grow house plants’, ‘cultivate herb garden’, ‘create a lawn’ and much the same choice of products pops up, without any explanation as to why you’d want one product over another.
And I had to check elsewhere to find a proper explanation of how biochar worked (although I found one on the Carbon Gold site eventually).
I’ve noticed that a lot of garden company websites are confusing in this way. A friend who works in retail recently told me that companies want you to focus on the products for sale, so any background explanations and ‘how-to’s are often made deliberately difficult to find.
I think that when you’re dealing with a new technology like this, more explanation would be better.
As for my friend who thought her gardener was wasting time by picking stones out of the border before planting roses in it – she is lucky to have someone who cares about the soil and does not treat her job merely as a ‘to do’ list. If you want a similarly good gardener, read how to find a gardener who is perfect for your garden.
More help for eco-friendly gardeners
There’s an old gardening saying ‘feed the soil, not the plant.’
Published at Sat, 27 Nov 2021 12:25:40 -0500