Make sure you plant your sweet peas in April or you’ll miss out on one of spring’s greatest pleasures.
One of the real joys of spring is being able to pick huge bunches of gloriously scented, home-grown sweet peas. And the best thing about growing sweet peas is that the more flowers you pick, the more they produce. I’ve grown both the bush and the climbing varieties and if you really want to pick for the vase, the climbing variety is best. However, you need to get them into the ground by the end of April.
For best results they should be grown in well-composted trenches 600mm deep and 400mm wide. Work a good handful of superphosphate or bonemeal into every metre of the trench. As sweetpeas can grow as tall as an average man and flower profusely they will require when they start shooting, a good fortnightly feeding in addition to what plant nourishment you have put into the trench. They also require good drainage as the greatest killer of young sweetpeas is overwatering. A net or chickenwire support should be erected before planting begins. Some people claim that sweetpeas grow best in ‘north’ to ‘south’ trenches and this has certainly worked for me when I grew them years ago in Johannesburg. Soak the seeds overnight to facilitate germination and then plant them 20mm deep and about 130 mm apart. A friend of mine germinates her sweetpeas in moist blotting paper and only when the tap roots are 25mm long does she plant them into the ground. She claims this gives a better survival rate with fewer gaps.
When the plants are about 150mm tall pinch back the growing tips (this will be above the second or third pair of leaves) to induce the plants to bush out. As the plants grow tie them regularly to the support, keeping only two stems per plant, and cutting away all unnecessary tendrils and side shoots. This way all the strength goes into the flowers. Once they are growing nicely, regular deep watering will be required, and, as mentioned a fortnightly feed with a liquid fertiliser of your choice. Sweetpeas usually take 100 days to flower, so it is possible to organise their flowering for a special future occasion.