SDR treated and film coated spinach breeding lines for the organic market. SDR (Short Day length Requirement) is a priming treatment which will stimulate the spinach plant to bolt more easily and uniformly. Speed of bolting and flowering may be improved to more than a week. Furthermore the SDR treated plants produce more side shoots on which flowers are carried and express less stress symptoms before and after bolting. SDR treated spinach does not need to be sown in the autumn. It may be sown in spring, limiting the risks during wintering of spinach plants. SDR treatment may be used on male and female lines in order to obtains synchronized flowering. It has been shown that SDR treatment on female lines could improve yield (under optimal seed production conditions). When SDR is used correctly, it will result in less inbred seed during hybrid seed production. The organic SDR variant may be used in Dutch organic farming.