Green thumbs and tight fists
Green thumbs, more often than not, come attached to tight fists. We gardeners can’t walk through a public garden without filching a cutting or pocketing a seed pod. We haggle over horse manure – $2 per sack seems reasonable, but $3 is daylight robbery! – and prefer to consult Dr Google for soil health hints rather than a professional laboratory.
For less than a hundred bucks, you can send sample cores off for analysis to find out your soil’s pH; how much phosphorus, potassium, calcium, magnesium and sodium it contains; its cation exchange capacity (a measure of fertility) and base saturation (a clue as to whether you need to add lime or not).
Or you can spend $20 on a cheap DIY kit that, as far as magic tricks go, is considerably less exciting than pulling a rabbit from a hat. Take a handful of dirt, tip it into a small plastic vial, add a splash of pH solution, shake well and all – or at least your soil’s relative acidity or alkalinity – will be revealed.
That’s the theory, but the first (and last) time I used a DIY kit and held it up to the rainbow-coded chart for comparison, I honestly couldn’t see any colour other than brown in my test tube of muddy water.
It would have been more telling to simply plant a few hydrangeas and sit back for a season or two, for these horticultural litmus testers are natural chameleons, their petals tending towards blue in acid soil or pink in alkaline conditions.
Gardeners’ proclivity for parsimony is obvious when you search the web for horticultural life hacks.
Up come hundreds of hints, most quite mad, such as sowing seeds in broken egg shells or recycled bog rolls, lining hanging baskets with disposable nappies (for extra moisture retention) and adding vodka to your vases to make cut flowers last longer. Some of the advice is practical. For example, if you want to know if your soil is drought-prone or floodprone, dig a 10-litre-bucket-sized hole, fill it with water and let it drain. Then refill and set your stopwatch. If it empties in less than a minute, you have free-draining soil; if the water level doesn’t drop in half an hour, you’ve got drainage problems. Mind you, a winter stroll across your lawn is similarly revealing. If your slippers disappear into the sludge, you need some new Novaflo pipes.
The other DIY way to get a handle on the health of your soil is with a texture test. Take a handful of dry soil, add a splash of water and knead it in your hand. If it immediately crumbles, you have sandy or silty soil. If it can be rolled into a bliss ball, you have loam. And if you can squeeze it into the shape of a decent-sized dog turd, you have clay.
Clay soil can be a nightmare. It cracks in summer, sticks to your spade in winter and slowly suffocates the roots of finicky fruit trees. On the plus side, it clings to its nutrients as well as your gumboots.
To loosen heavy clay, dig in compost, sow leguminous cover crops and work in gypsum (calcium sulphate). Get cracking on these jobs now, while the soil is still warm and reasonably dry, as working wet clay does more harm than good.
Adding gypsum improves soil structure through a process known as flocculation, in which clay particles bond with the calcium, rather than each other, which slowly increases friability.
Over time, that prevents crusting and cracking in summer, improves drainage and cranks up beneficial microbial activity, so you don’t hit pockets of anaerobic (rotten-smelling) soil when you’re digging.
Life hack: you can buy gypsum – it’s sold as Clay Breaker in garden centres – or you can raid the skip bins on building sites for unwanted bits of plasterboard and smash them into a fine powder. It’s the same stuff.
But if you’re battling clay and making no headway, the best advice is to build no-dig raised beds on top of it, grow roses (they actually like clay soil) or make friends with a potter.
When my green-fingered mate Fiona Henderson, a West Auckland ceramic artist, sank her spade into a patch of deep clay while helping me plant hostas last spring, she took that stubborn clod home and beat it into submission; it’s now an earthy glazed pot for frothy gypsophila and rhodohypoxis bulbs.
(And, no, in case you’re wondering, it isn’t lined with a nappy.)
Gardeners' proclivity for parsimony is obvious when you search the web for horticultural life hacks.