Frost and flavour
ICOULDN’T believe my eyes a few mornings ago when I woke up and glanced out the window. It had been an unexpectedly cool night. Our battered lawn was spotted with worryingly white patches.
The frost layers were even thicker over the straw mulches around our cabbages, kale, parsnips and swedes.
Actually, that made me happy because these are vegetables which develop greatly improved flavours and become much sweeter after being frosted a few times.
I’ve always noticed how frost seems to form more heavily on grass or where straw and similar mulching materials are used.
It rarely appears on bare, dry ground. This clearly reveals the reason frost forms. It happens when moisture given off by plants or from mulches in late afternoon begins to settle again during cold nights, freezing as it does so.
In fact, it explodes the persistently repeated myth that mulches “keep the soil warm” as though acting like electric blankets.
Just the opposite happens because mulches insulate the surface of the soil, sealing it off from the warming effects of sunlight.
This is the real reason why during the colder months, heavily mulched soil is always much colder than exposed, bare soil.
Fortunately, last week’s relatively light frosts did little damage.
I had all our harvested pumpkins spread out in the open to harden off after being cut free.
And I was careful enough to cover them the previous evening with a big sheet of fairly dense shadecloth.
When pumpkin skins become even slightly burned by frost you can be sure that rot will immediately spread from the point of damage. All were saved and have now been carted under cover for long storage.
The SnoGold sweetcorn seedlings that germinated last November have been steadily reaching full maturity over the past couple of weeks.
Heavy rains in March came at a perfect time, just as the kernels were forming and swelling.
The results were in the wonderful size of the sweetcorn cobs.
All are sweet and juicy with beautiful cream- gold colours.
The extra water at a crucial time ensured there were no missing kernels or “baldheaded” cobs a common problem after long, dry summers.
Luckily, even heavy frosts around harvesting time will not damage cobs because they are securely enclosed and totally protected by leafy sheaths.
In fact, sweetcorn leaves can be bleached white after being killed by frosts, yet cobs remain perfectly safe and still taste just as delicious.
Tomato plants are different. Most of ours withered away a couple of weeks ago.
However, I decided to extend the lives of three good producers and also some capsicum plants still bearing good crops.
That meant protection from frost. A sheet of clear plastic film was roughly strung over the tops of these plants, supported by few garden stakes rammed into the ground.
Not a pretty sight, but this cover is now proving valuable and will give us extra supplies of tomatoes and capsicums, even until midMay.
All surpluses are cooked to a puree and deep- frozen for excellent winter and spring eating mainly as sauces, casseroles and soups.
About five weeks ago I planted a good selection of winter brassica seedlings including savoy cabbage, broccoli, cottager’s kale ( Two Peters) and mini- caulies.
They went into enriched soil, spurred along with weak applications of fish emulsion, seaweed concentrate and compost water. They are now doing beautifully and need only an occasional Dipel spray with to keep late caterpillars under control.
Savoy and Sugarloaf cabbages develop magnificent flavours during Tasmania’s cool winters but, unfortunately, have a tendency to burst their heads as they mature.
Many keen growers despair about this unsightly head- splitting, but all it does is make exposed, damaged hearts turn darker green.
This is no big deal because it ensures bursting cabbage heads are even more nutritious. Even so, I still planted a selection of mini- ballhead cabbages, four to the square metre. They will be ready to harvest from late July through to late September.
Weak, heavily diluted doses of fish emulsion over the past few weeks have ensured all brassicas have now formed good rosettes of big leaves.
That’s all they need to be able to easily cope with the inevitable cold, wet soils and chilly winter conditions, typical of Tasmania.
This eliminates the common problem of premature bolting into flower in the middle of winter.
A- MAIZE- ING: Corn is one of the few crops not adversely affected by frost.