A Guide To Prize Winning Sweet Peas
If you want to grow amazing sweet peas you should start now. Traditionally gardeners sowed sweet peas in the autumn, overwintered them in cold frames, and then planted out in spring. Many still do. However sweet peas are versatile hardy annuals. You can get them going indoors, or sow them later outside in big containers or directly into the open ground. What’s interesting about them is their enduring popularity, other flowers come and go but sweet peas remain firm favourites through generations of gardeners.
All keen sweet pea growers have their secrets and particular ways of growing them. Before writing this I did a little research on “the right way” to sow and grow sweet peas. Some soak them, others nick the seeds with a knife. Some sow several seeds in a pot, others just one seed in a large pot. Some start them in the warm, others grow them cold. But it is always worth remembering that there are usually several ways to achieve great results. Your amazing sweet peas will be the result of skill, experimentation, experience, and more than anything else, luck!
Here’s my step by step guide to growing amazing sweet peas.
1. Buy fresh, quality seeds. Personally I would choose to buy selected varieties to get the colours I want and most of all to ensure I get heavily fragrant ones. The choice is yours; there are certainly plenty to choose from. If you do intend to scoop the prize at your local flower show, choose varieties recommended for exhibition.
2. First and foremost prepare the planting position. I would do this now, even before you sow the seed. Sweet peas need moisture; dry conditions cause bud drop. They also like plenty of nitrogen for growth and potash for flowers. Dig the ground over and if possible dig out a trench or a flat bottomed hole to a depth of 45cm (18”) or so and fill with a layer of compost with fish, blood and bone mixed in or well-rotted manure. Backfill with soil mixed with manure or garden compost.
3. Sow the seed. It is worth soaking the seeds for a few hours before you sow. I sow in deep fibre pots or root trainers. The latter are those long tube-like cells with vertically ribbed sides. Sweet peas have long tap roots and they need depth. Use a good quality growing medium suitable for seeds.
4. Keep the pots of seeds moist and in a light position that’s not too warm. A cool conservatory is ideal, or a greenhouse that’s almost frost free. Alternatively on the window ledge of a cool room. Avoid electric propagators and excess heat, they will produce weak, leggy plants.
5. As the seedlings germinate they will shoot up and then stop. Don’t panic. They usually get weak at this stage and it is time to pinch the tops out. Keep them cool and light. If the weather is mild you can stand them outdoors in the daytime or transfer them to a cold frame. Apply a weak liquid general fertiliser once a week. This is important because that seed compost has little in the way of nutrients.
6. There is a fat bud lower down on the stem of each seedling. Once the top has been pinched out this starts to grow out and will be the main stem. Sometimes several stems develop. This can depend on variety and often more branching happens once the seedlings are planted out. I think it pays to give some support to the individual plants at this stage: just a thin green cane or a straight twig. It makes them easier to handle.
7. Once you’ve hardened them off you can plant them out in mid spring. Get your supports in place, whether you are using traditional canes, hazel rods or fancy obelisks. Make sure they are tall enough. In my experience sweet peas never start to flower well until they are at least 1.2 metres (4ft) high. Some of the old fashioned and small flowered varieties are shorter. So for standard varieties 1.8m (6ft) is really essential.
8. As the plants grow, tie them into the canes. Use soft ties or sweet pea rings. These are small aluminium rings that go round the stem and the cane. Some say remove the tendrils because they weaken the plants. This simply isn’t true. They are green so they photosynthesise supplying the plant with more nutrients. Their disadvantage is that they often wrap themselves around the flower stems making them bend awkwardly.
9. Now here’s the essential: regular watering and feeding with a liquid fertiliser. If they get dry, the buds drop. If they run low on available nutrients they suffer. This is where that compost or manure below the plants comes into its own. It acts as a reservoir and helps to keep the water and nutrients near the roots. Incidentally you can use turf in the bottom of the hole if you have any.
10. As soon as they start to flower keep picking. Never let any fade on the plants and start to develop seeds. As soon as seeds start to develop flower production slows down and may stop altogether. Hormones from the seeds tell the plant the part is over and it’s done its job.
What to feed your sweet peas with?
My mother always used dried blood mixed in water. Our garden was on clay and this seemed very successful. I might use tomato fertiliser of Miracle-gro which is a soluble general fertiliser with loads of potash. We all have our favourites which produce amazing results; with a bit of luck!