September 2011 Tattler.pdf - Platypus Country

GARDENING
Planting time
At this time of year the longer and brighter days make us
keen to get started in the garden particularly in the
vegetable plot. We are so aware of our short growing
season that we often plant too early, motivated by the
hope that crops will mature before cold beats us again.
The two critical pieces of knowledge that should guide
our actions when dealing with warm season plants are:
Soil temperature controls growth above all other
factors; and
Night temperature has more positive effect on
growth than either day temperature or sunniness.
Soil Temperature. To get the earliest rise in soil
temperature in Spring requires that the maximum amount
of light is allowed to fall on the bare soil surface. This
means that at this time of year management decisions
should prioritise this one factor. To prepare for the
planting of warm season crops the most effective action is
clearing away mulch and ground cover such as weed and
grass.
Warming can be hastened by temporarily covering the
area with plastic to intensify heating and reduce heat loss
at night. This action requires some judgement. Plastic left
on or too long may build up so much heat that soil
organisms die which interferes with the soil vitality. (This
is a technique called soil solarisation that is used to
fumigate soil pathogens).
Completely covering a large area prevents entry of water
and oxygen which also reduces soil health. In a large
garden bed try laying plastic in metre wide strips with a
space of 20cms left open between them. This allows heat,
water, oxygen and soil organisms to migrate horizontally.
At Delegate School we ripened watermelons last season
by leaving a black plastic 30cm square around the base of
the plant. This kept the main root area warm and did not
interfere with water and oxygen exchange. The runners
were allowed to stretch over soil and the path made of
bark chips. If we had covered the whole area with plastic,
the heat generated would have been detrimental to soil
and root health and the heat reflected from the surface
would have cooked the vine. In addition, water pooling on
the plastic surface would have surely generated fungal
disease (mildew). Most importantly we restricted each
vine to producing only two fruit.
As the season progresses water management becomes the
priority and this is when mulch comes into its own. Mulch
is also useful in the peak of the summer as it holds down
soil temperatures which can become so high that growth
is inhibited. In our area soil heat may be a temporary
negative factor in the growth of cold climate and shallow
rooted plants such as camellias that are often the basis of
perennial gardens in this district but is not usually of
consequence to vegetable crops. If water permits
maximum growth of vegetables usually occurs with a bare
Susan Tocchini
soil.
Night Temperature. There is little that can be managed
to great effect in the open garden. Placing covers etc. is
time consuming whereas cloches and tunnels are growing
techniques with their own specific challenges.
Growing in the peak of the season and restricting planting
to suitable varieties gives the best and most efficient
production. Nursing crops through adverse weather
conditions is time consuming and ultimately
disappointing. So wait a month or six weeks to plant out
the warm season crops such as tomatoes, zucchini,
pumpkin, peppers and even longer for corn. In the
meantime warm the soil in preparation for these and in
other beds concentrate on crops that take a bit of cold like
coriander, parsley, radish, lettuce, peas, spinach, carrot
and potatoes etc. See Deb's comments below.
September plantings
Spring is in the air and the urge to get planting is very
strong. Since seeds and seedlings are expensive, we need
to ensure the best chance of survival for our plantings. Its
rewarding to see plants emerge from the soil but heartbreaking
to watch them shoot up to seed before giving us
any food or going black in frost.
Local conditions
There is no one ‘right’ time for planting in our region
with its great variation in altitude and temperature. It
helps to have had experience with local conditions or to
ask someone who has. Jo in Deddick can plant up to a
month before I can in Cabanandra; and Bonang is
doubtless later again. Goongerah may be more like
Deddick, only wetter. Unfortunately our seasons aren’t
longer at the other end to make up for it! Crops that can
safely be planted in September in most places include:
Onion and celery seedlings (too late for seed)
Carrots
Parsnips
Beetroot
Lettuce and other greens
Brassicas: cabbage, cauliflower, broccoli (but
remember they will have to fight the hot summer
heat at about the time they are ready for harvest)
Deb