This week's tips for your garden
Green manure crops can continue to be dug in and the ground
prepared for seed-sowing by breaking down the surface with a
fork and raking it level.
Dig green manure into the top 15cm of soil only, as the
organisms that convert green manure to humus are more
Green manure crops, such as mustard and oats, which make
rapid growth at this time of the year, can be sown in garden
areas not needed until late summer or autumn. Mustard is
closely related to the brassica family (Brussels sprouts,
broccoli, cabbage), so if those crops are to be sown in the
space, choose oats or barley for the green manure.
Do no digging if the soil is wet.
This is especially important with heavy clay soils, as they
become concrete-like when they dry out after being dug when
Any swedes, carrots, parsnips and leeks still in the ground
can be lifted and heeled in a corner of the garden to clear
the way for sowing new seed during the next few weeks.
Parsnips freeze well: peel, cut them into serving-sized
pieces and freeze without blanching. Parsnips require a
longer growing season than other root crops. Any time from
now until the first week in October will give seedlings the
good start they need.
Poorly drained soil can be improved by pouring about 1cm of
sand in the bottom of the seed drills. Cover the seed with
more sand. Avoid sowing parsnips in recently manured ground
or they will develop forked roots.
Ground which last had cabbage, cauliflower or Brussels
sprouts grown in it is suitable.
Add garden lime (30g/sq m) and a dusting of superphosphate
Parsnip seed quickly loses its vitality, so fresh seed should
be bought each year. Parsley is best sown in a position
accessible in all weather. The herb can be sown now and likes
a soil rich in organic material and slightly acidic i.e.,
without lime added. Sowing now and again in autumn gives
parsley for year-round use.
French beans, sweet corn and salad plants can be sown under
cloches or old windows. Place the covers in position for at
least three weeks to warm the soil before sowing tender
crops. This method can also be used to sow cabbages,
cauliflowers, lettuce and silverbeet earlier than in open
Jerusalem artichokes require a long season of growth and, if
not already planted, should be put in as soon as ground can
be prepared. Peas should be sown in small quantities. Little
and often gives pea crops over a longer period and avoids the
problem of them all being ready at once and going to waste.
Silverbeet from autumn sowings will respond to a weekly
application of liquid manure and a fortnightly pinch of
sulphate of ammonia sprinkled around the roots and hoed in.
In warmer districts, hardy annuals can be sown where they are
to flower. As with all seeds, the trick is to have the soil
well-prepared before sowing. Once seedlings appear, thin them
out to prevent overcrowding. Hardy, prolific and reliable
flowers include alyssum, calendula, coreopsis, candytuft,
cornflower, clarkia, godetia, Californian poppy
(Eschscholtzia), larkspur, linaria, linum, night-scented
stock (Matthiola bicornis), mignonette, love in a mist
(nigella), pansy and viscaria.
Nasturtiums flower all summer in full sun or partial shade.
They do well in poor soil but are frost tender so should not
be planted out until the danger of frost has passed. Modern
varieties such as Black Velvet, Empress of India, Peach
Melba, Whirlybird types and the semi-double Salmon Baby are
more compact than older trailing types and do not take off
across the garden.
Perennials to raise from seed from now until the end of
October include granny bonnet (aquilegia), dianthus, dahlia,
delphinium, gaillardia, geum, gypsophila, hollyhock, lupin,
penstemon, polyanthus, pyrethrum and viola.
These will all flower within 12 months and some will bloom in
their first season.
Start them in trays of seed-raising mix, then plant them in
the open garden when they have made some growth. They can be
transplanted into their permanent positions in autumn.
Peach tree leaf curl attacks peach, nectarine and almond
trees. Active and damaging in late spring and summer, it
should be treated now. Disease-causing fungus spores
overwinter in the buds and bud scales of the host plant. They
spread rapidly once the leaves appear, distorting them with a
wrinkled, red appearance.
An early spring fungicidal spray can control attacks. Use
lime-sulphur (1:30 spray to water) or a Bordeaux mixture
applied at the end of this month, just before the buds begin
to open. Or spray with copper oxychloride (25g powder to five
litres water) before the buds open. Do not use sprays on hot,
sunny days as they may cause scorching.