Narcissus and Daffodil

80 G.R. Hanks
Figure 4.4 A typical bulb planting machine feeding bulbs from a hopper into two
ridges (Photograph: Horticulture Research International).
rate should be calibrated by adjusting the hopper aperture or the speed of
the delivery belt. High planting rates may be difficult to achieve with standard
machinery, and blockages often occur, so that constant attention from the operator
will be needed. When planting in flat beds, small or uniform bulbs are
planted using a row planter, planting four rows at a time. Larger bulbs are planted
using bed digging and filling machines that lift the soil and transfer it to the adjacent
planting bed.
‘One-’ or ‘two-year-down’ growing
Rees et al. (1973) compared one-, two- and three-year-down narcissus growing in
south-west England, and concluded that costs were too high for a one-year-down
system to be economic. UK narcissus growers now use this two-year-down growing
system, half of the stock being lifted and re-planted in alternate years. This
‘biennial’ growing involves some loss of bulb yield, because an ideal planting
density obviously cannot be achieved in both years. Too low a planting density is
inefficient in the first year, while too high a density results in subsequent overcrowding.
At a planting density of 10 t/ha, half the bulb weight increase occurred
in each year in two-year growing, but at high densities all the increase was in the
first year (Rees et al., 1973). Some data (ADAS, 1993) are illustrated in Figure 4.5.
In ornamentals production, however, when most bulb growth takes place in the
first year, this has the advantage that higher flower yields are obtained in year two,
and there are high yields of relatively small bulbs which are advantageous for
retail bulb sales because they produce more flowers per tonne. The flowers produced
in the second year are unaffected by any adverse effects of HWT two years
earlier, so quality is improved. There is also an element of ‘compensation’ in yield,