In the last three days Sydney and most of eastern NSW have experienced cyclonic conditions and the highest daily rainfalls in decades. Our garden has received 260 litres of rain per square metre – that’s over half a ton of water on a surface the size of a double bed! It was even worse in some areas north from Sydney or nearer the coast.
So how does your garden hold its drink? Did you check it up yet?
Yes, it is a scary thing to go back there after heavy rains, walking across squelching lawns, muddy patches and puddles to see flattened plants and broken flower stalks. All these fallen leaves, various objects strewn around by the gale and broken branches waiting to be picked up – feels like a hard clean-up operation.
But it is not as bad as it seems, the greenery is lush and with warm weather still ahead the plants will bounce back quickly, especially with some help.
First, try not to cause more damage. Do not trample the paths near plant root zone because wet soil easily gets compacted and becomes hard when dry, preventing roots from growing through it. If the compaction already happened, aerate the soil by sticking a garden fork into it and wobbling it front to back, creating channels for the air and water.
Look for soil erosion caused by streaming rainwater and don’t make it worse by stepping on and collapsing the undercut edges. If erosion uncovered plant roots, cover them immediately by backfilling the runnels. Water follows the path of least resistance downhill – did you create nice, easy channels for it by the way your garden is laid out? Maybe it’s time to rethink the design.
To prevent soil from escaping down the drain, create water traps (such as swales, pits or bog gardens) which slow water flow. Planting across (rather than down) the slope and good mulch cover also help to retain the soil. And before you top up mulches, do not forget to add more nutrients to replace those leached from the soil by rainwater. Add compost and other relevant fertilisers and conditioners, such as wood ash, animal manures, seaweed or blood and bone.
The opposite of erosion is pooling of water. Unless it happened in your pond or bog garden, try to drain the affected patch quickly, because stagnating water causes root rot in older plants and total collapse of young, partially submerged seedlings. It will be also a breeding ground for bacterial and fungal plant diseases. Dig channels lined with stones or bricks or use pipes to remove the excess water. It is also a good time to check for potential mosquito breeding places in buckets, bowls or pot saucers.
Small plants flattened by rain, but which do not stand in water or waterlogged soil may straighten up on their own if left undisturbed. While they recover, remember that the aftermath of heavy rains is the best time to plant and sow seeds. Get your winter vegetables going, they will grow well and fast (as will weeds, but that’s another matter!). Just watch for slugs and snails; either hunt them after dark with a torch or set traps (beers traps or hiding places like overturned pots) to decimate them before things gets out of control!
Check out compost heaps and worm farms (especially if left uncovered during rains). Soaked compost soon becomes anaerobic and starts producing unpleasant smells. Fork in dry (high carbon) materials: straw, hay, dry leaves, wood shavings or sawdust. Mix well; this allows for air access to the inside of the heap to aid aerobic decomposition. Add more paper and straw to your worm farm and do not forget to check the farm outlet for blockages to avoid drowning the little creatures when next rains come.
The sun will shine again and after a temporary setback your garden will flourish in deeply watered soils.
And after all, what is rain, but an excuse to get a new pair of gumboots?