Sweet Pea sowing dates and growing guide
This is Laurie's self-reminder guide for sowing in the warm
temperate
northern districts of New Zealand. The cultivars are mostly
Keith Hammett cultivars, and the information on sowing months comes
from the packet label. The growing advice is a compilation from all
over the internet. Use this at your own risk.
General
Most sweet peas are summer flowering types. They must have over
twelve hours of daylight each day before to initiate flowering. Sow
between June and October inclusive. If sown much after this they
can't initiate flowers, and will not flower until the following
summer. Keith Hammett says not to soak the seeds before sowing. He
also says if the seeds are being grown in pots, keep the pots in
full light and not in a greenhouse. Summer sweet peas will
germinate and grow (slowly) in the cool conditions of winter, but
take off as the soils warm in spring.
Winter flowering types are rapid growing, but generally have only a
single main stem. Winter flowering strains need only 10 hours or
less to flower.
Sow February and March for winter flowers.
Stems hold 3–6 flowers. Some modern varieties usually carry 6
flowers to the stem.
Seed sowing
Seed can be direct sowed, but the soil must be well drained, in a
sunny position, and slugs and snails kept off them.Seedlings are
ready to plant out at about 4 to 6 weeks from sowing.
Site & Fertiliser needs
Pick a sunny site and plant out into moist, rich, deep, loamy soil.
Ideal pH is 7.0–7.5, and some claim sweet peas grown at this pH have
much larger leaves and are larger plants. Sweet peas are heavy
feeders. Plant seedlings 20-30cm. Sweet peas tolerate very light
(dappled) shade, and it is beneficial in hot summers. Ample organic
matter helps hold moisture and helps sweet peas tolerate heat.
Presumably mulch will as well.
Encourage plants to bush out by nipping out the top two leaves as
soon as plants have grown four leaves. This stimulates new side
shoots, which means more stems and, ultimately, more flowers.
Several applications of a high phosphate fertiliser during active
growth might be useful to maximise plant health and flowering.
Disease
A spray with a fungicide in spring, around late October/early
November, will help suppress powdery mildew.
When to sow and Flowering Season
February for winter flowers - High Society, Solstice White, Solstice
Crimson
March for winter flowers - High Society, Solstice White, Solstice
Crimson
June for late spring/summer flowers - Blue vein, Just Maybe,
Original wild Sicilian, Shell Pink, Somewhere, Solstice Crimson,
Little Red Riding Hood
July for late spring/summer flowers - Blue vein, Just Maybe,
Original wild Sicilian, Shell Pink, Somewhere, Solstice Crimson,
Little Red Riding Hood
August for late spring/summer flowers - Blue vein, Just Maybe,
Original wild Sicilian, Shell Pink, Somewhere, Solstice Crimson,
Little Red Riding Hood
September for late spring/summer flowers - Blue vein, Just Maybe,
Original wild Sicilian, Somewhere, Solstice Crimson, Little Red
Riding Hood
October for summer flowers - High Society, Solstice White, Solstice
Crimson
November for Autumn flowers - Solstice Crimson
Bijou dwarf November December January February March April