SOIL IMPROVEMENT IS THE KEY
BUT WHAT DO YOU USE?
I’VE recently concluded a three-Friday tour of towns in the Western Downs Council region, including Bell, Jandowae, Dalby, Tara, Wandoan, Chinchilla and Miles.
Firstly, I must say that in every town I was made to feel more than welcome, and that I thoroughly enjoyed speaking with a group of gardeners who showed their resilience and true grit during pretty tough conditions for them and their gardens.
My main topic for discussion was all about improving water efficiency in gardens, and one of the main points I stressed was to improve soils so that they could hold more water for longer.
We started with one irrevocable horticultural principle.
Get your soil in good shape and you can’t help but grow quality plants.
Now, I’m sure I’m not telling you anything new here.
Most gardeners practise soil improvement by utilising a variety of methods and materials.
In many instances, the materials selected for incorporation into the soil are usually forms of animal manures and/or composts.
And unless you live on a farm or have rural “connections”, most forms of manure and compost are purchased in plastic bags from your local nursery (of course, you can make compost at home too).
So, how about we take a look at the pros and cons of using manures and composts, fresh from the farm, and “fresh” from the retailer, in our gardens.
Firstly, a quick look at farm or paddock fresh manures.
These can be literally straight from the animal, very raw and quite strong.
By strong, I mean quite possibly damaging to plant growth.
Most fresh manures contain high levels of ammonia, which can literally burn plants if applied too soon.
Some feedlot manures are very high in other salts as well, a fact which I discovered a few years ago when quite a few of my garden plants were burnt by seemingly “safe” aged feedlot manure.
Fresh manures can also harbour organisms that can be damaging to human health.
In addition, they can contain huge numbers of fresh and undigested seeds, which can germinate quite readily in any garden to which the manure has been added. So, what to do with fresh manures?
You can incorporate them into moist soils and leave them for a minimum of around 6-8 weeks.
This will allow the soil organisms and rainfall/irrigation to commence the decomposition process and significantly reduce high levels of damaging ammonia and other salts.
I’d suggest leaving this stuff alone for at least two months if you’ve dug it in.
Or, you could mix it into your open compost bin and let it break down with other organic materials, helping to dilute the nasties normally associated with fresh poo.
The ideal animal manure has been aged, or to quote from the quintessential gardening book or TV guru, is “well-rotted”.
What’s the pick of “natural” manures for the garden?
If you’re looking for bang for your buck (highest nutrient content), then poultry manures usually top the list, followed by cow, sheep and horse all vying for second spot dependant on their origins.
Of course, don’t expect spectacular and instantaneous growth from aged manures.
They are very low in nutrients and release them slowly as they rely on soil organisms to find, chew (20 times please), digest and excrete them in forms that your plants can use.
Some gardeners prefer sheep manure as it comes in a naturally “pelletised” form.
Secondly, let’s have a gander at the bagged products sold by your local nursery or retailer.
These are generally sold in 25 litre bags and come with the usual descriptive names Cow Manure, Sheep Manure, Poultry Manure, Premium Compost, 5IN1, Soil Activator, Mushroom Compost, to name a few.
They’re all pitched at the gardener who wants to add some organic matter to improve soil structure, as well as some nutrients, and then plant the garden fairly well straight afterwards.
Once again, similar to potting mixes, be mindful that these are organic materials and are subject to the ravages of time, moisture and heat whilst in their plastic bags.
I’ve opened some of these products, only to be assaulted by an overpowering odour of ammonia, a tell-tale sign of decomposition in the bag.
Some seem to be mainly manure-flavoured sawdust, and others display the dark, fine consistency and “earthy” smell of real composts.
Like potting mixes, an Australian Standard, AS4454, has been developed for composts, soil conditioners and mulches.
If you can find a product manufactured to this standard, it should comply with benchmarks for pH, salinity, particle size, plant toxicity, and wettability, to name a few.
Some of these products are also approved by Australian Organic, which should also add to your confidence when selecting and using them in your garden.