How to grow parsnip plant
Cultivation It is essential if you expect to produce good-sized specimens to trench the soil deeply so that the desirable, long, straight, unforked roots are produced. The large seeds are sown in 2.5cm (1 in) deep drills in small groups at intervals of 10cm (4in), the drills spaced 45cm (18in) apart. Choose a calm day for sowing as the seeds are light and liable to blow away in windy weather. Do not try to transplant as this will generally result in some injury to the essential tap root. Should all your seeds germinate you may remove alternate plants in the drills leaving the remaining ones at 20cm (8in) intervals.
The best soil is one which has been well manured for a previous crop, and no animal manure should be applied later. However, a stimulant may well be given in the form of a mixture of 85g (3oz) of superphosphate, 28g (1 oz) of sulphate of ammonia and 42g (1oz) of sulphate of potash per sq m (sq yd). The roots will be ready for use at the end of October but, since they are frost resistant, they may be left in their rows until they are needed; or, if the soil has to be dug in preparation for further cropping, the roots may be lifted and packed away in a shed or cellar with a covering of dry soil or sand. In any event it is always wise to lift and store a few roots in case the ground freezes hard, making it impossible to dig up the roots.