Your pots or trays of seedlings and freshly-sown seed are sitting pretty on a windowsill indoors, or in a frost-free glasshouse or polytunnel. To protect them and freshly-sown seed from extremes of heat, always provide sufficient ventilation on bright spring days and keep the pots and trays out of direct sunshine. The smaller the seed, the closer to the surface of the compost you should sow it. In particular, using a high-quality seed compost is essential in terms of supporting good germination rates and healthy growth. This discourages the plants from developing what’s known as “blindness”, where leaves but no flowers appear.
