It’s time to start raising tomatoes – and take a punt on warmer weather to plant them out in November. By Margaret Simons.
The best time for planting tomatoes, my gardening books tell me, is when the night-time temperature is consistently above 10 degrees. Another way of knowing is to thrust your finger into the soil. If you can keep it there for a minute with no discomfort, then the soil is probably ready.
When I lived deep in the country, a neighbour advised me that the way to judge soil warmth was to sit on the ground with bare buttocks, and I actually did this. In my inner-suburban Melbourne garden, with the McDonald’s at the back fence and the queue for the post office at the front, that doesn’t seem advisable. Even though, just between us, I am mad.
The night-time temperatures are not yet warm enough in Melbourne for tomato seed. Like many gardeners in the southern states, I start my tomato plants indoors in pots to get a jump on the season.
Thanks to lockdown I have not been to Bunnings. I am reliant on the things I have at hand or can make myself. For that reason, I am forced to reuse last season’s potting mix as I prepare for the growing season. That’s okay; I have done it before and have perfected the technique and some workarounds. Doing this is a great way of earning sustainability brownie points, but it’s a messy business and not for the squeamish.
I really should wear gloves for this kind of job, but I can never stand using them in the garden. They make my fingers too bulky and crude, robbing me of the sense of touch. Instead, I plunge into the dirt bare fingered and try to make up for it later by scrubbing and lathering with sanitiser.
So yesterday I made my mix. First, I harvested the muddy worm-castings from the bottom of the farm that sits under the mandarin tree. I picked out the things the worms seem to find indigestible – chiefly avocado seeds and skins but also the occasional sticky label proclaiming the remains of a Batlow apple or Queensland mango. You could use your own compost if you don’t have a worm farm.
I tipped the worm mud into a tub and left it in daylight so the worms – which are programmed to avoid predators – would squirm to the bottom, making it easier to scrape the good stuff from the top.
Meanwhile, I sterilised a tray of last season’s potting mix by putting it in the oven for half an hour at 100 degrees. No hotter, my gardening book said, or you could create toxins. I used a meat thermometer just to be sure. Just as well it is months since I could hold a dinner party. Future guests: I sterilised the thermometer afterwards.
This was the first time I have used the oven in this way. Normally, if I want to sterilise old potting mix, I cover it in black plastic and leave it in the sun for a succession of hot days. But the sun is not yet hot enough and the tomatoes must be started.
Having assembled my ingredients, I got a big plastic bucket and tipped in the cooled potting mix and a roughly equivalent volume of worm castings. To this I added a handful of fertiliser (I’d put in more than a handful if it was for established plants) and half a bag of perlite (heated and crushed volcanic rock). I was lucky to have this left over from the previous gardening season. Vermiculite (a silicate) is also good.
If neither of these is available, I have in the past used coarse sand. The idea is to aid drainage and stop the soil from becoming too heavy and compacted. Perlite and vermiculite also hold nutrients and retain water, so, if you have them, they are better. But when Bunnings is closed, we must make do. For sprouting seeds, use more perlite, vermiculite or sand to keep the mixture light. For established plants, use just enough to keep the water flowing through and stop everything clogging up. It’s a bit like making muffins: you can use judgement rather than precision.
Having assembled my ingredients, it was time to mix. In the loneliness of my locked-down backyard, up to my elbows in muck and having not spoken to a three-dimensional human being for days, I chanted to myself like a wicked sister from Macbeth:
Double, double toil and trouble;
Fire burn and caldron bubble.
Fillet of a fenny snake,
In the caldron boil and bake;
Eye of newt and toe of frog,
Wool of bat and tongue of dog,
Adder’s fork and blind-worm’s sting,
Lizard’s leg and howlet’s wing …
And so on. I have, after all, been feeling like a witch. My grey hair is long and unkempt. My solitude is deep and my imaginings are my most intense company. As I mixed, a stray worm was my only observer, if worms can observe. Have others become so unhinged? If so, gardening is no cure, but it does help you feel more at home with your madness.
The potting mix was ready. I was still singing. It was time to contain the magic and put it to use. I brought out the little pots I save each time I buy a plant from Bunnings. I poured a kettle of boiling water over them to sterilise, then filled the bottoms with crushed eggshells, saved from a hundred boring omelettes eaten on my lap in front of Netflix.
Crushed eggshells aid drainage. At a pinch, you can use them instead of perlite or sand in your potting mix. I nearly always put them at the bottom of pots. I piled my mix into the pots and went back into the house, trailing mud and worms, to find the plastic clip-lock box in which I keep seeds.
There were two half-used envelopes of tomato seed, another of cucumber, one of eggplant and an old pillbox full of burry coriander, harvested when the bushes went to flower last autumn. The seeds looked like little flakes and whorls of gold and silver when I sprinkled them on top of my cauldron brew. I raised my filthy index finger and pushed them under.
It seems so unlikely, when you combine seeds with soil, that anything will result. They look so tiny, so impotent. Not at all like a capsule of life. There are so many parables about seed cast on stony ground or baked too fast by the sun. There are so many ways in which the enterprise can miscarry. And yet, almost as often as not, it works.
My tray of pots filled with homemade mix now sits on my dining room table next to the window. I look at it at every meal. A worm or two has crawled out and perished on the wasteland of the tray.
I can expect to wait for a fortnight or so, and then tiny plants, thin as cotton, will push their way through the soil and begin to unfold into their full selves. The traditional time to plant out tomato seedlings is the weekend before the Melbourne Cup – unless there are sudden chills, gales or 40-degree stinkers.
Who knows where we will be, or even who we will be, by then? Will the crowds gather, with their hats and shoes and gaudy ways? Perhaps I will have had a haircut. Perhaps I will have trimmed and scrubbed my nails, removing the signs of my backyard degradation.
Perhaps by Christmas I will be harvesting my tomatoes, slicing them for salads and barbecues and dinners to which I will invite friends, and I will have cleaned the house, and everything will be warm and new. By then, perhaps, I will have forgotten that I went mad for a while, stirring my cauldron of magic muck in the crisp chill of early spring.
This article was first published in the print edition of The Saturday Paper on Sep 25, 2021 as "Cultivated tastes".
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