words: Diana Noonan
Ash dos and don’ts
Use only ash from wood (not coal), and then, only from untreated wood.
Cool the ash thoroughly before using on the garden or in the compost.
If storing the ash, keep it thoroughly dry.
Scatter, don’t concentrate, the ash, and dig
it in just a few centimetres.
Use ash little and often.
Pest control
Some gardeners believe wood ash, scattered around the base of plants, and replaced after rain, kills slugs and snails. Other gardeners find no success with this form of organic pest control (which may simply mean they’re not applying the ash in the best way).
Don’t fret if you’re fire-less
Comfrey, with its long roots, harvests nutrients from deep in the soil and is an excellent source of potassium. Brew it into liquid fertiliser or make a concentrated batch by covering a bucket of leaves and leaving them for a few weeks to rot down. Citrus (all the better shredded) is another source of potassium so don’t throw away those skins or old fallen fruit. Compost them instead.
I can’t wait to light my fire. I know I’ll miss the warm days of autumn and summer; I know I’ll grumble about the mess: the crumbs of wood on the floor and the ring left on the mat by the ash bucket, and the chore of chopping and splitting and filling wood baskets. But I’m looking forward to that exciting snap and crackle of kindling as flames leap into life, the lovely red glow once big blocks of wood have been burning for a while, and the soft hiss of the kettle on the hot plate. And I’m looking forward to the ash which, all winter and spring, I religiously carry out to sprinkle on the garden or the compost pile.
There’s something quite ancient about this ash-applying routine. Slash-and-burn cultures were among the first peoples to recognise that ash sites were ideal situations for planting new crops, and ‘gardeners’, in the sense of those who tilled formalised plots of soil, used ash from their indoor fires to enrich their beds. The value of adding wood ash to the garden is that it delivers to the soil potassium, one of the most important elements in plant growth, and the ubiquitous ‘K’ listed as one of the three essential ingredients on chemical fertilisers.
Potassium is a mysterious soil nutrient in that it is essential to plant health in so many, almost indefinable, ways. It controls the uptake of carbon dioxide (a gas as vital to plants as oxygen is to us), it regulates the movement of water in plants (and helps improve drought resistance) and gives plants that boost of energy needed to carry out the complex chemical processes that result in their growth.
You’ll soon know if your plants are lacking in potassium. A worrying yellow edge to middle and lower leaves is a tell-tale sign, as is unexpected leaf drop, especially in situations of drought or sudden temperature change. Potassium-starved plants just don’t have the ability to hang in there at times of stress. And they will often be stunted and slow to grow, even in the best of climatic conditions. Add to all this a poor resistance to pests, weak roots and problems with uneven fruit-ripening, and you, too, could be reaching for the ash bucket.
When potassium was formally identified as desirable in the garden, commercial producers were quick to find ways of producing it. Their method of concentrating the element from ash, however, was anything but speedy. Ashes (and those from hardwoods were preferred) were collected in pots of water (hence the old name for potassium: ‘potash’) and left to leach. The resulting liquid was evaporated by boiling or baking, and what was left in the pot was potassium. But not enough to supply the needs of everyone who wanted it. Fortuitously, for gardeners and horticulturalists, potash was discovered in many parts of the world in a mineable ore (rock) form, from which it could then be more easily extracted.
But to return to the ash I produce in my home fire, although it takes a lot of wood to make a little ash, and an awful lot of ash to make a little potash, the plants in my organic garden look pretty darned healthy so I assume my practice of scattering wood ash is working. If the worms in the compost are anything to go by, I’d say it has to be. Wood ash raises the alkalinity of the material it mixes with (this is another way of saying it ‘sweetens’ or raises the pH level of garden materials) and red compost worms need this ‘sweetness’ to thrive. My fruit-bearing plants (which must have a healthy dose of potassium) are cropping well, especially the gooseberry and currant bushes that sport strong wood and show no sign of leaf browning. My tomatoes (the few I get in my southern part of the world) ripen evenly, the stems of my brassicas are stout and strong,and heading varieties (cauliflower and broccoli) are large and compact. In the ornamental garden, the flowers are big and bright.
Not all plants enjoy sweet soils, however, and I take care to avoid scattering ash around acid-loving bushes, such as blueberries, camellias and rhododendrons. I also keep the ash well clear of potatoes, which tend to develop a scabby skin in response to too much potassium.
With any luck (and despite all the garden knowledge one accumulates, it seems that ‘luck’ has a good deal to do with results) my garden will get enough potassium over the colder months to see it right through summer and autumn. By which stage I know I’ll be only too happy to find myself lighting the fire again. There’s nothing quite like a flickering flame and a healthy dose of fertiliser.
