Autumn Chill

It’s autumn in southern Australia and plants are beginning to slow down as soil temperatures fall and daylight hours rapidly drop away. All this starts once Easter is over and the first rains bring the soil back to life; the autumn chill is coming.

Only a month ago I was protecting seedlings against too much sun and heat. Shade cloth over new seedlings produced the worst seed table I can recall in a very long time. One week they were thriving (photo on the right) and then – phlat!

The most likely problem is that the commercial ‘premium’ potting mix I used lacked sufficient nutrients to provide these seedlings with the energy they needed to cope with extremes of heat and shading, no matter how carefully I watered them. So what started out as excellent piece of planning – an early start to the autumn plantings – turned into a near-disaster, with many seedlings lost.

So the seed table was moved to a sunnier spot, new potting mix obtained from a more reputable supplier, and new seeds planted. All the usual winter stuff - red, brown and white onions, orange and purple carrots, kohl rabi, beetroot, parsley, tatsoi, whitlof, all sorts of flowers (for the Spring display), mitsuba, mitzuna, filderspitzkraut, chives, garlic chives, Black Spanish and Miyashiga White radishes, raddichio, endives, ‘Fat Hen’ salad greens, ‘Freckles’ cos lettuce and thyme.

More netting is dragged out of the shed to cover these seed trays before the blackbirds get in there and flick up the potting mix in their search for worms; the fragile seedlings are all too easily buried.

The ‘home paddock’ garden bed has been dormant all summer for lack of available water; this has been mulched and watered and the soil restarted to receive these autumn/winter crops and the remnants of the summer seedlings.

April brings the first serious rains we’ve had in over six months; weeds and remnant vegetable seeds spring up all though this soil. Direct-sown lettuce does particularly well, along with broccoli, cauliflower, ‘rapa’, silverbeet and corn salad (‘Feldsalat’ in German). It doesn’t look like much now, but it will all get sorted before the soil cools too far.

All this goes on while the last of the summer crops are harvested – pumpkins, zucchinis, basil, eggplants (aubergines), capsicums (peppers), beans, avocadoes, grapes and peaches. The citrus trees – mandarins, grapefruit, oranges and lemons – are already starting to show colour.

And the current soil temperature? Over in the production garden soil temperature is monitored automatically and continuously. I need only log onto the internet to see that the long slow slide into winter is upon us. So now it is a race to get those seed-table seedlings to a sufficient size to plant them out before cool soils stop them altogether.

Home-made soil nutrition

Mid-Spring and two months since we’ve had rain on the Adelaide Plains…

About now I’d normally be starting to see the late winter crops drying out and I’d be struggling to start seedlings in drying soil.

But just for once I’ve got the ‘covers’ on the garden in time; a deep layer of barley straw – about 60 bales – covers all the working beds, paths and the orchard floor. Soil moisture levels are under control, needing only 10 tonne of water per week (10 000 litres) to hold steady.

But with watering and the seed table under control I’m forced to face a more insidious problem that’s been creeping up on me for some years now; the nutrition levels in these soils is starting to fall. This is particularly true along the edges of the garden bed (mesh) fences where I grow beans and cucumbers year after year.

Fortunately we’ve been saving kitchen scraps – imported nutrition – for a decade now in three Gedye bins that have been in constant rotation. Each bin takes at least a year to fill even though we throw in a bucketful of scraps each day and occasionally add green cuttings from the garden and a shovel or two of soil. Where does it all go?

So I choose the oldest bin and pull the tapered top off (the bottom is open). Compost worms everywhere! These worms - Tiger worms, Indian Blues and Red Wrigglers - are different from earthworms; they live on the surface and enjoy moist, cool, dark, oxygen-rich places with lots of food scraps to eat. This lot seem particularly fond of the cook’s lecture notes that she dumped in there; they are living between the sheets of these thick wads of old A4 paper and loving it.

This job stinks.

But I wouldn’t know – at sometime in the past I lost my sense of smell, so I’m the perfect guy for this work.

The top layer of the heap is set aside, the worms are moved to the two remaining working Gedye bins by the shovelful, the nutrition-rich worm castings at the bottom of the bin are loaded into the wheelbarrow and sieving begins.

Old cake trays make great coarse sieves for such compost, removing old bones, sticks, avocado pips and other bits of hard rubbish.

New bean trenches are hoed along the fence lines and ‘Lazy Wife’ bean seeds are dropped onto the trench floor with compost then straw mulch added on top; these large bean seeds will push through this as they germinate.

I add a brand-new drip line to totally saturate the root zone so that the beans can get out into the moist surrounding soil for extra nutrition. The cook helps out by planting the cucumber seedlings, adding compost and back-mulching as well.

And that’s that.

Except that – a day later – there’s still a funny smell lingering around wherever I am. Even I can occasionally detect it.

Luckily the cook is away at a seminar in the Barossa Valley or I’d be sleeping down the back-shed tonight…

How to make soil

Soil – as distinct from dirt – takes years to create. Building soil is the real job of the gardener, and is a task that goes on year after year while annual crops come and go. Building soil requires the cooperation of the cook, for much of the nutrients from kitchen scraps are recycled through compost bins or the chicken flock back to the soil. Buying in compost is a quicker route when soils are degraded or new areas are opened up, but once good soils are established, they must still be fed and developed in the background to growing fruit, vegetables and herbs.

Good soils smell warm and rich, are friable (crumbly) and soft, easily dug, full of worms, and dark with organic matter. These soils are not dug over, except for when rows are hoed for planting seedlings. Good soils are always protected from the sun and moisture loss by mulch – bare soils die, because the worms that upgrade the organic matter in soils to something acceptable and palatable to plants cannot work in hot hard dry soils.

It’s Day 56 after sowing seed, and the last of the seedlings – capsicums and eggplants – go into soil that has been a decade in the making. With the spring crops in, the summer round of re-sowing will recommence over the coming weeks, with rocket and lettuce seeds for salads, more celery and carrots to join the beetroot for juice, and early winter crops such as cauliflower that need to be sown in the warm months. These will go into the beds currently raising slow-growing garlic, onions and leeks that need six months to mature between the coldest and hottest parts of the year.

In the meantime though, its time to make more soil – the potatoes need ‘hilling up’. 85% of the new tubers grow above the original mother potato, and the green stems of maturing potatoes (from whence new tubers will come) are starting to fall over whenever the wind blows.This ‘hilling up’ puts soil around the potato stems, which will push out more roots, segments of which will swell to form the edible portion.

Digging for these potatoes is one of the few processes used in this garden to turn over soil and to break new ground; potatoes are often the first crop into beds that have been dormant for years. So creating new soil is a good way to add compost onto then into old patches, and potatoes are the ideal vehicle.

Making soil is simple enough, though it won’t be ‘real soil’ for some time to come. Clay (dug up during recent plumbing operations) and aged and air dried compost are both put through the shredder to break them down, then mixed in equal parts in the barrow before being shovelled around the potato stems after their mulch cover is pulled back.