(French Parsley) The true variety, Plain Leaved Parsley is absolutely unsurpassed for flavour. Companion Plant: Said to improve the health and vigour of roses and tomatoes when grown next to them. Height: 30-60cm (12-24in).Grow in ordinary soil in sun or part shade, but for best results prefers a rich moist soil. Soak seeds overnight before sowing. Sow seeds outdoors from spring to mid summer, 1cm (½in) deep in drills 30cm (12in) apart.Thin out to 23cm (9in) apart. To harvest, pick over all the plants regularly to encourage fresh growth.