How to Grow Pansies and Violas from Seed

Growing pansies and violas from seed opens up a much wider range of varieties than buying plug plants, and is considerably more economical when you need plants for large displays or containers. The process is straightforward once you understand the two quirks specific to this genus: seeds germinate best in relatively cool conditions (unlike most summer annuals), and they require darkness to germinate reliably. Get these two conditions right and germination is fast and consistent.

Choosing the Right Compost and Containers

Use a fine-grade seed and cuttings compost rather than multi-purpose compost. Seed compost has lower nutrient levels (high nutrients burn germinating seeds) and a finer texture that allows delicate roots to penetrate easily. Fill clean trays or modules to within one centimetre of the rim, firm gently, and water from below by standing the tray in water until the surface darkens with moisture. Drain thoroughly before sowing — the compost should be evenly moist but never waterlogged.

Sowing Method: Darkness Is Essential

Sow seeds individually on the surface of the compost, spacing them about two centimetres apart in trays or one per cell in modules. Cover with a thin layer of vermiculite or fine compost to a depth of approximately 3–4 mm — just enough to block light. Pansy and viola seeds require darkness to germinate; seeds left uncovered or inadequately covered on bright windowsills will have significantly lower germination rates. After covering, gently firm the surface and water lightly with a fine mist.

Germination Temperature: Keep It Cool

The optimal germination temperature for pansies and violas is 15–18 °C. Temperatures above 20 °C inhibit germination significantly, which is why sowing in a warm propagator in midsummer leads to disappointing results. A cool, shaded bench in a greenhouse, a cold frame, or an unheated spare room is often better than a heated propagator for summer sowings. For winter or spring sowings indoors, the germination area should be cool rather than warm. Cover trays with black polythene or place in a dark cupboard to maintain darkness, and check daily for signs of germination.

Pricking Out and Growing On

Germination takes ten to fourteen days in ideal conditions. Once seedlings have produced their first pair of true leaves (the leaves after the rounded seed leaves), they are ready to be pricked out into individual 5–7 cm pots or module trays filled with multi-purpose compost. Handle seedlings by a seed leaf rather than the stem — pinching the stem causes damage that can let disease in. Grow on in a cool, bright position, ensuring good ventilation to prevent damping off, until plants are large enough for their final container or garden position.

Hardening Off Before Planting Out

Plants raised indoors or under glass need to be gradually acclimatised to outdoor conditions over one to two weeks. Begin by standing them outdoors in a sheltered position for a few hours each day, increasing the exposure daily. After two weeks they will be ready to plant out in their final positions. Young pansies are relatively cold-tolerant but should be protected from severe frost in the first few weeks after planting out.