Q: I grew sweet peas this summer and loved filling the house with their flowers. The plants have finished and I was going to clear them away to the compost heap but noticed a lot of pods on them. Can I collect the seed from these to sow again next spring or is it best to buy fresh seed? Mary K, Waterford
A: Homegrown sweet pea is one of the great joys of the summer garden, not just for the beauty of its delicately pretty flowers but also its powerful perfume, a seductive scent that can fill a room. The good news is that it’s perfectly possible to home-save the seed and then use it to grow another generation of plants to fill your garden with fragrant blooms next year. Sweet pea flowers are typically self-pollinating with pollination taking place before the flowers have opened, so they should also come true to type in terms of the flowers closely resembling those of the parent plants.
Just make sure that the seed pods have fully ripened before harvesting. They should be pale golden-brown, dry and firm to the touch while the seeds inside them should be brown-black and hard. Store them in a strong paper bag or envelope and in a cool, dry, dark, rodent-proof spot until you’re ready to use them.
For best results as regards germination, chit the seeds by placing them on damp kitchen paper in a sealed, clear plastic container put in a bright cool room for a few days, opening the lid briefly once a day to allow in fresh air. Once the baby root radicles and shoots appear, gently transplant each seed into its own small, deep pot or root trainer filled with a good quality seed compost, lightly cover them with another layer of compost, water generously, then place them somewhere cool but frost-free, bright and rodent proof, ideally on a table or propagating bench. A couple of protective layers of fine netting will help to deter mice from stealing the seeds which they find irresistible
As you probably know, this hardy annual is a naturally short-lived species that lives no more than a year. Seed can be sowed in October-early November or in early spring, both of which will produce plants that will bloom next summer. The benefit of an autumn sowing is stronger, more vigorous, earlier flowering, more floriferous plants, but you do need to protect the young plants from temperatures below -4 degrees as well as from slugs, snails and rodents. For this reason, they’re best grown in root trainers in a bright, cool spot over winter under the cover of a frost-free glasshouse or polytunnel and then planted out into their final growing positions in late March/ early April. For optimum results, give them a warm, sheltered, sunny position and a rich, deep soil and protect the baby plants against the cold with a blanket of Enviromesh.
