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2 Siting the home garden for the fruits of
love There's hardly a vegetable or fruit that is
grown anywhere, but in an open sunny aspect, with good drainage. It's a source of constant
amusement to me that coffee-table gardening books revel in the ubiquitous description for
all of their vegetable entries, "requires a frost-free open sunny aspect with
free-draining soil". Not every gardener has the luxury of such conditions and yet we
all manage to grow with varying success enough of most fruits and vegetable to keep us
happy, so obviously they all grow with less than optimum conditions. Or at least there are
some cultivars that will tolerate the less-than-ideal conditions.
While sunny gardens are needed for the best crops, some
ingenious devises produce great Tomatoes in shaded gardens. You won't be so successful
with the Capsicums and Chillies, but they grow well in containers anyhow, so you can move
them around to catch the sun. The use of tall wire supports, trellises and bamboo tripods
to get Tomato plants up into the sunlight are very successful. Use the strong climbing
cherry varieties, such as 'Cocktail Supreme' or the vigorous indeterminates which all need
a sturdy stake, such as 'Grosse Lisse', 'Mighty Red', 'Moonshot', 'Tropic' or 'Riverdale
Red', depending on your area. The reason that Tomatoes need sunlight rather than just
heat, is that they are mostly pollinated by bees, who happen to work better in sunlight
and when the air temperatures are above 11oC.
Many home gardeners are thwarted from ever producing good
produce by invasive roots from their shade trees or from their neighbours' hungry trees.
You can legally trench all around your own vegetable beds to a depth of 300mm, which would
take out most of the offenders' shallow roots. Some very keen gardeners even place a
physical barrier of poly film into the trench and back-fill it, or you could use a barrier
of gravel or even concrete, but with nothing more than a good dig three times a summer you
will remove most of the offending feeder roots and still preserve good-neighbour harmony.
The free draining nature of soils for any folk who garden
on the Keilor Plains, Adelaide Plains or the clay soils of Western Sydney will immediately
be understood. They use gypsum by the bucket full, which at 1 kilogram per square metre on
the alkaline soils and lesser applications of dolomite on the acidic clay soils will
dramatically improve drainage. Even within two hours! Of course the use of lots of compost
is also great and by building up the garden beds so that water never lies on the beds,
will see very healthy crops too. You can even grow Tomatoes, Capsicums and especially
Eggplants on bitumen paving! They love the extra heat coming off the pavement. All it
requires is to fix a frame of railway sleepers on edge and fill the beds with 300mm of
compost and loam. This provides nutrients and good drainage as well as some moisture
retention from the loam, because Tomatoes thrive where moisture is retained, but they rot
off if water lies at their roots for too long. If you are renting you can dismantle the
beds when you move so that the landlord's bitumen or concrete driveway is reinstated to
its original 'mint' condition. I've seen some very productive driveway gardens within
railway-sleeper raised beds. Ester Deans' gardening book: growing without digging ,
published by Harper & Row (Aust) Pty Ltd, Sydney (rrp $9.95) is a good read if you
want to try this technique. The no-dig garden appeals to young itinerants, who don't have
the freedom of re-landscaping their rented digs as well as the infirm.
Water quality is not quite the issue with Tomatoes and
Eggplants that it is with French Beans. The Tomatoes, Capsicums and Eggplants will all
tolerate up to 4000 ppm of dissolved salts providing there is good drainage. Brian Powell
grows a wonderful range of vegetables including enormous Tomatoes at Quorn in South
Australia's pastoral north, with bore water of that quality. The alkaline bore water can
be accommodated with lots of acidic compost. The Tomato in commercial production grows
best in a pH range of 5.8 to 6.8, but excellent results can still be gained from soils as
alkaline as pH 8.5, providing the beds are mulched with organic compost. This has the
effect of slowly leaching humic acid into the top 100mm or 4" layer of the soil where
most of the Tomato feeder roots are. At the very alkaline end of the spectrum, say pH 8,
potassium supply to the 'Fruits of Love' is severely restricted and since potassium is
needed to set fruit, your yields will diminish. The availability of organic iron also
becomes crucial in soils with a pH above 8, but gardeners on those soils probably know all
about adding iron chelates or sulphur to remedy that. The root run incidentally of
Tomatoes on light sandy soils will be quite deep, so they may well penetrate 450mm down
and about 200mm laterally on Perth's sand plains. On heavy loam a 200mm deep root-run and
a 450mm lateral spread would be quite normal. That means that the roots only travel 200mm
deep but about 450mm wide from the plant, so that's where they have to be fed. Planting
the bushes any closer than their root-run permits, only results in stunted plants with
reduced yields. Irrigators and gardeners who use loads of compost, can of course plant
closer, but on poorer soils, keep your distance! Local knowledge will tell you what is
best, so ask your local nursery folk or the gardener with the best garden in your suburb
or locality. Where ever I go in Australia, I'm always stickybeaking over fences. Even if
you run face-to-face into the gardener on the other side, a quick explanation that you're
a keen gardener, is usually met with an invitation to come inside and have a closer look.
The flattery is irresistible to most of us!
Warm soil temperatures are vital for Tomatoes in particular
to set fruit. That's why Tomatoes are planted out in southern Australia in spring as soil
temperatures are rising or in winter in the tropical north because their soil temperature
are always high enough for Tomatoes. The reason for winter culture in the northern tropics
and sub-tropics in Australia, South East Asia, Central America and East Africa, is that
the Tomato is plagued by many fungal diseases which are rampant in the wet humid tropics
during the wet summer. It's only the winter dry season in those regions that can produce
good crops in the open. In southern temperate Australia, South Africa and in New Zealand
we grow Tomatoes as a fresh summer salad crop, whereas in the tropics of Asia and
elsewhere, they are cooked rather than eaten fresh, because they don't store well in the
tropics. Well without cold stores anyhow! In our tropics of course the Tomato is a
valuable cash crop for southern winter consumption, by those who cannot do without their
salads.
Atmospheric temperatures are critical for Tomatoes to set
fruit and every home gardener must appreciate the facts that H.D. Tindall at the Cranfield
Institute of Technology in Bedford England, reported in his tropical vegetable research.
His book is detailed in the references in Chapter 10.
Those were principally that.. "High atmospheric
temperatures above 27oC are likely to induce pollen sterility and high night
temperatures adversely affect flower initiation."
The importance of this is that while flowers will be
pollinated in November in southern Australia or August in the north, when daytime
temperature may well exceed 27oC, there are long periods of daylight when the
temperatures will be below 27oC. Once the fertilisation has taken place, the
fruit will continue to develop, however if the temperatures stay above 27oC
through the day and night, no fertilisation takes place and no fruit develops. A further
requirement borne out be researchers is that there also needs to be a diurnal fluctuation
of at least 5-6oC within the 21-27oC range. Night temperatures of
between 16-20oC are ideal and temperatures below 13oC severely
affect the pollination of most Tomato cultivars. No pollination... no fruit! This explains
why so many of our best mid-season fruiting Tomatoes have a lapse in fruit set if we get a
few weeks of plus 35oC heat. The Tomatoes formed before the heat wave will
continue to develop, but no new ones are evident. In some of our inland areas, subjected
to long heat waves, keen gardeners like Brian Coots at Marla in Central Australia, will
hose their Tomatoes down at dusk and the latent heat of vaporisation causes a cooling
effect for long enough to affect pollination. Fremantle's cooling 'Doctor' and Adelaide's
'Gully' winds on a hot night have a similar effect and even leaving the side gates open on
a hot night can help!
Eggplants and Chillies can take the hottest spot in your
garden, providing they experience no frosts during the growing season. It goes without
stating the obvious, that Tomatoes can't handle frost either. If you try to beat the gun
with planting out too early in spring, you can crib some success by watering with seaweed
extracts. The seaweed extract adds alginates and minor trace elements to the soil and
plants, which assists greatly in their ability to withstand light frosts. I really don't
know why, but it works. Dahlia growers are avid users of these seaweed extracts because of
its effect of reducing the destruction by frost on their late blooms in autumn.
You will now have located your Tomato patch at least in
your own mind. I know the family negotiations are probably not completed, but that's your
worry. Don't forget that you had best grow the Tomatoes somewhere other than where you
grew them last year, due to the likelihood of diseases spreading from that patch to your
super new crop. |
