Whether growing annuals or perennials, producing flowers from seeds provides your garden with beautiful colours, shapes and varieties for amazing value.
Growing flowers from seed is cheaper than buying mature plants and with some simple sowing tips, you'll be rewarded with a wealth of attractive plants.
When to grow flower seeds
Always read, and keep, the flower seed packet. This will have advice on planting times and aftercare.
- Seeds that can be started indoors, in a greenhouse or heated propagator, can usually be done so in February or March.
- Planting seeds directly into outside soil or outside containers, called direct sowing, will usually be from April or May onwards.
How to prepare the soil for flower seeds
If you’re growing seeds indoors in trays or containers, use a specialist seed compost with the correct levels of nutrients.
For direct sowing, check with the seed instructions for the best type of soil and compost to use.
Always remove weeds before planting, though, and take out soil stones and rake over to get a crumble-like top level.
Water the soil immediately prior to direct sowing, rather than after flower seed planting has been done.
How to sow small flower seeds indoors
- Check the individual seed packet for precise instructions.
- Small flower seeds, like lobelia, can be sown in seed trays.
- Fill the tray with seed compost to the top.
- Then press the compost down evenly, leaving a 0.5inch (1cm) gap to the top of the tray.
- Place the tray in a shallow water pool, so the soil slowly absorbs the moisture from below.
- Sprinkle seeds evenly and lightly on the soil surface.
- Cover seeds with a fine layer of the compost, or better still, with vermiculite (drainage material).
- When you water from the top for the first time, add a fungicide to the water to help protect against ‘damping off’ problems.
How to sow large flower seeds indoors
Large flower seeds, like sunflowers, can go into larger single containers with a depth of about 4inches (10cm). Plant one seed per pot, if the instructions say so.
Use seed compost and plant the seed about 1inch (2.5cm) below the surface, covering over with compost afterwards.
Water well from the top, using a small watering can with a rose sprinkler attachment.
How to sow flower seeds outdoors
When indoor-grown seeds are large enough to be potted outside, and when the soil is warm enough, seedlings can be taken outside and transplanted directly into the soil.
- Harden off indoor plants first before external planting. Do this by placing them outside during the day to adjust them to the temperatures.
- For direct flower seed sowing, use a rake to make a shallow v-shaped trench, or drill, to plant seeds in just below the surface.
- Scatter seeds by hand into the trench, or plant individually with larger seeds, according to packet instructions.
- Lightly fill in the soil over the seed trench with your hand. Water the soil to keep it moist but be careful not to saturate.
How to thin out flower seeds
Flower seeds, particularly those scattered loosely by hand, will probably need thinning out as they grow to remove weaker seedlings and create space. Pull these out by hand, remove any visible weeds also.