This much loved hardy annual climber is a world-wide favorite. Provided you give it a good, deeply dug, well drained, rich soil it will reward you with a harvest of sweetly scented blooms in the widest possible range of colors on almost a daily basis.
In fact, the more you cut the flowers for the house, the more it will produce.
The variety I grow, which you see in the video, is "Lathyrus odoratus Cupani" and -- if your Latin is a little rusty -- let me point out that "odoratus" means scented and, boy, it surely is! This particular variety is one of the earliest sent to England from Sicily in 1699 by Father Cupani. I have found it to be far hardier in extreme weather conditions than the more modern -- and more delicate -- F1 hybrids.
Owing to its hard casing, sweet pea seeds can be hard to germinate. Because of this, some people advocate cutting a small nick in the seed casing. I prefer to soak the seed in tepid water overnight. I then put the seed on moist tissue in a plastic container with a lid and place it in a warm place, checking frequently. As soon as one or more seeds have germinated I plant these in a long pot, made of rolled up newspaper. This encourages long, roots to form from the start. At planting out time, you can place the entire paper pot and rooted seedling in the soil, thus avoiding any check to the smooth growth of the plant.
And seeds which have yet to germinate (they do tend to be a bit erratic) can be left in the plastic container until they germinate.
When the seedlings are 5 cm (2 inches) high, you should pinch out the growing tip to make them produce plenty of strong vigorous side shoots.
Plant them out in a sunny spot well away from shade in deeply dug, well drained, richly composted soil, tied to a bamboo stake. A good plan is to plant four or five bamboos in a circle and tie the tops together, wigwam style. You can put several of those wigwams in one bed and, in the cool of the evening, the scent from twenty plants or more has to be experienced to be believed!
Once the flowers appear, cut them as soon as they have opened fully and you can continue to cut flowers for the house in increasing amounts all summer long. In fact, you should cut every day to encourage flowers and make sure no flowers are missed which then set seed, otherwise your flowers will stop coming.