The single genus Brassica
provides the cornerstone of the average vegetable
plot. Botany books talk about B. bullata, B. capitata,
B. gemmifera and so on, but to us they are cabbages,
brussels sprouts, etc. Not all are leafy vegetables
– both turnips and Swedes are brassicas
and so is kohl rabi. But for the gardener the
word ‘brassica’ is usually reserved
for the varieties grown as greens – the
all-important group which flourish so well in
our climate and which share the same cultural
likes and dislikes. Brassicas have been a staple
part of our diet for thousands of years –
long before newcomers like potatoes and runner
beans came to our shores. But we must forget old
prejudices – in recent years there has been
a steady stream of new brassica varieties offering
new tastes, and during the same period our ideas
about the way to cook brassicas have also changed
– the days of school cabbage and boarding
house brussels sprouts should now be a thing of
Secrets of success
· Do not grow brassicas on the same plot
more often than one year in three. The main reason
for this move-around is to avoid the build-up
of soil pests and diseases which thrive on the
cabbage family – the dreaded club root disease
is the prime example.
· Dig deeply in autumn – the roots
must be allowed to reach the water reserves well
below the surface.
· Brassicas require firm soil – leave
several months between digging and planting in
order for the surface to consolidate.
· Lime if necessary – brassicas will
disappoint if the soil is acid. Aim for a pH of
· Transplant at the right stage and make
sure that you plant firmly.
· Sprinkle Bromophos around the base of
each seedling if cabbage root fly has been a problem
in the past.
· Many pests and diseases can attack brassicas
– treat problems as soon as they are seen.
Leafy Brassicas that can be sown in a seedbed,
then transplant to a permanent bed:
Broccoli - All varieties.
Brussels sprouts - All varieties.
Cabbage - Nearly all varieties.
Cauliflower - All varieties.
Kale - Nearly all varieties.
Leafy brassicas that can be sown where the plants
are to grow to maturity: Rape kale varieties.
· As shown above, nearly all leafy brassicas
are planted in a seedbed and then transferred
to another part of the plot where they will grow
to maturity. In this way the ‘permanent
bed’ can be utilised for another vegetable
until the seedlings are ready for transplanting.
· Choose a sunny but sheltered spot for
the seedbed. The soil must be fertile –
if it was not manured for a previous crop then
add compost when digging is autumn. Before sowing
rake (do not fork) the surface and add a general-purpose
fertilizer. Incorporate Bromophos if cabbage root
fly is known to be a nuisance in the area. Tread
to remove air pockets and to make the surface
firm – rake lightly and then follow the
sowing instructions for the specific brassica
you plan to grow.
· The permanent bed (the area where the
plants will grow to maturity) should be deeply
dug in autumn – ideally it will have grown
peas or beans a few months earlier. If the soil
has not been recently manured it is essential
that compost is incorporated during this autumn
· Do fork over the ground in spring –
simply tread down, rake lightly and remove surface
debris. A firm footing for the seedlings is essential.
· The seedlings will be ready for transplanting
5-7 weeks after sowing – look up the specific
brassica for details. Water the row the day before
the seedlings are to be lifted.
· Lift carefully, retaining as much soil
as possible around the roots. Do not dig up too
many at one time, and keep the roots covered so
that they do not dry out. Mark out the planting
row with string and make holes at the required
distances with a trowel or dibbler – if
the soil is dry fill the holes with water and
begin transplanting once they have drained.
· Look up the specific plant for details
of planting depth. Make sure that the plants are
properly firmed in with fingers, dibber or the
back of a trowel. To firm in with a dibber, insert
it 2in (5cm) from the seedling, then press towards
the plant so the soil covers the roots. Then perform
the tug test – tug the leaf, which should
tear before the plant is uprooted.
· Water the base of each transplant as
soon as planting is finished – keep the
rose of the watering can to ensure that the plants
will not be disturbed. If the weather is warm
and dry before the transplants are established,
cover them with newspaper and water the soil frequently.
Kale is generally a trouble-free vegetable, but
the other members of the brassica family are subject
to a wide range of pests and diseases. The worst
of these brassica enemies are:
Cabbage root fly
But you must not assume that an insect or fungus
disease is the cause every time something goes
wrong. The most likely cause of blown brussels
sprouts, heartless cabbage and button-headed cauliflowers
is you – the ground was left spongy of the
seedlings were not planted firmly. You may have
left acid soil un-limed or you may have planted
a brassica crop in land which produced poor cabbages
or cauliflowers last year. If you are new to gardening,
read the appropriate section carefully before
growing one of the brassicas. Other troubles are:
White blister (White rust)
Leaf spot (ring spot)
Slugs and snails
Blown brussels sprouts
Cabbage stem flea beetle