Agriculture Reference
In-Depth Information
Preparation
Prepare the ground at least two weeks beforehand by adding plenty of compost
and a handful or two of bonemeal, as sweetcorn will do better on phosphorus-
and potassium-rich soil.
Sowing
To avoid damage to the brittle roots, sow corn singly in deep biodegradable pots
at a depth of 2cm, on a sunny windowsill indoors. Seeds can be sown as early as
mid-March if the weather is warm enough, but if a late cold snap checks their
growth they will never become strong plants; unless your tunnel is likely to be
consistently warm by the end of April, it is better to wait until mid-April to sow.
Sweetcorn germinates best between 20°C and 25°C and can rot rather than germi-
nate if the earth is too cold. Once up, it needs plenty of light. Try to keep some
seeds back to fill gaps in case the germination rate is lower than you hoped. For
the same reason, plant more than you intend to grow - if you can spare the
seeds, which are often sold in maddeningly small packets.
Note:
Dwarf French beans and sweetcorn grow very well together and don't
compete for nutrients; plant a few bean seeds along every two or three rows just
after planting out the corn seedlings.
Growing
Sweetcorn likes to be pampered. The protected environment of a polytunnel will
be far more sheltered than anything outside, and also gives you total control over
watering and drainage.
Plant the seedlings in a block rather than in a long row, at spacings of 15cm by
25cm. This is somewhat closer than is usually suggested for outside growing, but
with a good supply of nutrients in the earth and a warmer, longer season than
they would get outside the tunnel, you can aim for a bigger harvest from a
smaller space.
Sweetcorn is pollinated by the wind rather than bees or insects, and of course
there won't be very much air movement in a tunnel compared with outside. Once
you see pollen on the flowers at the top, give each plant a gentle tap and clouds
of it will descend on to the tassels of 'corn silk' (masses of long, fine, light green
hairs that grow from the top of the developing cobs) below. Each hair leads down
to one of the potential seeds on the cob, so each one needs pollination.
As the plants grow, new roots may emerge from the stem near to the ground.
Earth them up with compost or a mulch of comfrey leaves to give your plants an
additional supply of nutrients. Keep the area free of weeds, but be very careful if
you're using a hoe as the roots are shallow and easily damaged.
