Clear Mountain Garden Treasures

Clear Mountain Garden TreasuresCulture and Germination - Sweet Peas

Sweet Peas

Red / Pink White
Family Fabaceae
Name Lathyrus odoratus
Common Name Sweet Peas

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Sweet pea is a climbing annual with sprays of brightly coloured flowers that have a very nice perfume. Flower colour is quite variable and varies from whites to pinks, reds, through to purples and blues. Some flowers are bi-coloured. Plant in Spring for late Summer display or in the Autumn for a great display next Spring.


Depth: 1 cm
When: Spring, Autumn
Where: In containers for transplanting later.
Germination rate is approximately 90%. Seed takes approximately 2 weeks to germinate.
Shrivelled peas tend to give darker colours, so sow a mixture of smooth and shrivelled.


The secret to successful germination is to know and understand the seed coat. This is a thick water impermeable skin that covers the whole seed. All peas have a very small hole to allow water in through the seed coat. As the seed soaks up the water, it will swell, cracking the tough outer skin, thus allowing more water in and the embryonic plant to grow out.

First, soak your seeds in warm water (not boiling - the water out of your hot water tap is warm enough) for an hour. This step helps soften the seed coat. Fold one kitchen towel twice, place the soaked seeds between the folds and lay the towel flat on a saucer. Wet the towel, but not so much that it is submerged in water.

After 24 hours the peas should have doubled in size. Take them out of the paper towel and sow into containers with moist seed raising mix at a depth of not more than 1cm. Place a sheet of glass over the container to keep the moisture up. You may cover the seeds with newspaper to keep off the light but it is not necessary. Keep moist, but not soaking wet. Like a moist sponge - moist to the touch but not dripping.

After two weeks, you should see little plants pushing through the seed raising mix. Remove the newspaper cover. Prick plants out when they are about 7-10 cm high.

Some growers like to sow thickly on a very thin layer of seed raising mix. When the seed starts to germinate, but before a root system is formed (i.e., there is only a short stubby root), each plant is lifted and planted into a small container that contains potting mix on the bottom half and moist seed raising mix on the top half. The idea here is to minimise damage to the tender roots of the young plants.

You may also sow directly where the plants are to grow. Sow two to four peas per hole and later thin down to one plant. Protect from slugs and snails. Ground temperature must be above 5 degrees at night or the peas will rot.

It is said that shrivelled peas tend to give darker colours, so you should plant a mixture of both smooth and shrivelled seeds.

Sow in Spring / early Summer for a late display and in Autumn for a Spring display.

These plants are climbers and will need support - will grow to more than 2 metres if you provide the right support. Prefers neutral to slightly alkaline soils, with not too much nitrogen fertiliser. Mildew can be a problem if grown in humid conditions (like Auckland).







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