Sweet pea seeds require a little bit of preparation before planting. For best results, soak the seeds in water before sowing; treating seeds with a dose of nitrogen-fixing inoculant powder before planting will increase the crop's yield. You won't need to use much inoculant powder for it to be effective, but you can't use too much -- it's harmless. Plant sweet peas in a sunny spot with compost-enriched, well-drained soil.
Erect slatted folding trellises about four feet high to support the plants while they grow. You can also make trellises from netting stretched between posts or twiggy tree branches saved from pruning. Use a garden reel to mark the rows with string. Then use a hoe to make trenches for planting. Sow the seeds thickly (about an inch apart). Water well, about 1 inch a week, and keep the soil moist throughout the growing season. Fertilize every 2 weeks with organic fertilizer or manure tea. Cut flowers every few day to encourage continuous blooming.