Dahlia Cactus Hybrids
The real advantage in growing Dahlias from seed is that you get the best of both worlds. The first year will provide a very economical collection of bright flowers and each plant will produce tubers that can be carefully lifted at the end of the end of the season for storing and re-planting the following year.
Cactus Mixed produces large double blooms formed with slender pointed petals. This variety makes a lovely garden display and a superb cut flower because of its vibrant colour and its overall growing height of 90-120cm.
WHEN TO SOW
February to April.
WHERE TO SOW
Sow the seeds in trays of moist seed compost and cover with a fine sprinkling of compost or vermiculite. Place in a warm place and keep at a temperature of between 20-25°C (68-77°F).
WHAT TO DO NEXT
When the seedlings are large enough to handle, prick off into trays 5cm apart. As seedlings grow, transplant into 9cm pots and gradually harden off before planting out in the flowering site from late May onwards. Space plants 60cm apart.
Reducing the amount of flower buds per stem will increase the size and quality of the blooms produced.
FLOWER SEED SOWING TECHNIQUE
HALF HARDY PERENNIAL BUT TREAT AS HALF HARDY ANNUAL
Use seed trays or plastic modules and a good seedling compost, preferably using a peat substitute. For small sowings standard pots can be used.
Firm the compost lightly and moisten before sowing. Very fine seeds, like Begonia (where there are more than 60,000 seeds to a gram) should be mixed with dry horticultural sand to avoid one big clump of seed, and to help see where the seed has been sown.
As a general rule, the depth of sowing depends on the size of the seed. Aim to cover the seed with compost or vermiculite to the same depth as the size of the seed. Very fine seed need not be covered at all.
Sow thinly and cover the tray with a sheet of glass with paper on top. Wipe the glass every day and inspect the tray for signs of germination. Sowings in pots can be enclosed in a polythene bag for the same effect.
As soon as seedlings break the surface, remove the glass and paper or polythene bag. If left under glass they will become leggy and weak. Keep moist with a fine spray.
When the first set of true leaves (not the seedling leaves) have formed they should be pricked off into trays, setting the seedlings about 4-5cm (1 1/2-2") apart. Always handle by the leaves and not the stem and use a fork or knife blade to ease them out of the compost. Keep in the shade for a couple of days after pricking off.
Gradually harden the plants by increasing ventilation and moving the trays into a cold frame and finally outside for 7 days before transplanting into the flowering site.