Sweet Peas are actually very easy to grow. You can simply plant them in the soil where you intend them to grow in March or April in the UK (be guided by local weather conditions) and leave them to it. By July you should have flowers. However, to get the best from your seeds you should consider planting them in autumn or winter (October to February). This will enable you to have stronger and earlier flowering plants.
How to sow:
* Sow one seed to a 3 inch (8cm) pot or to each cell of 5” Rootrainers®;
* Alternatively, sow 6 to 8 seeds to a 6 inch (15cm) pot;
* Use you favourite multi-purpose compost and ensure seeds are covered by no more than ½ inch (1cm) of compost after sowing;
* Do not firm the compost but water the pots with a fine rose to allow the compost to settle and to start germination;
* Some people like to soak the seeds overnight before sowing, or nick the seed coat, on the side away from the 'eye' or scar on the seed, using a razor blade or by gently rubbing with sandpaper. Research shows that this is not necessary and that it actually reduces germination in softer seeded varieties. If you must soak the seeds, do so for no more than four hours prior to sowing;
* Some people prefer to pre-germinate seeds in moist warm conditions prior to sowing and this can be done without harm;
* Treating the seeds with a fungicide or bio-stimulant may help germination;
* Place the pots in a cold frame or cold greenhouse and protect against mice and slugs, if necessary;
* Germination should take place after two weeks;
* If you are sowing in November to February your seeds may need a little gentle heat to germinate;
* Make sure you move them to a cold greenhouse as soon as the young shoots break the surface of the compost, otherwise your plants will get elongated or ‘leggy’;
* Overwinter your seedlings in a cold frame or cold greenhouse, bringing them up as hard as possible;
* Plants should be kept in full sun to give them as much light as possible in the winter months.

How to look after your seedlings:
* The seedlings will tolerate light frost and should be grown as hard as possible, for example moving the plants out of the glasshouse as much as possible and especially on sunny winter days;
* Take precautions against slugs, snails, mice and birds (and cats who may find them to be a tempting bed);
* Watch out for bad weather and protect against damaging winds. When hard frosts are forecast, say below -5 Celsius, your seedlings will need some extra protection. Close the frame’s lights and add some lagging (eg newspaper, bubble wrap, sacking etc). If the weather is particularly cold or the frosts prolonged, leave the lagging on to allow the seedlings to thaw slowly;
* Some people like to nip out the tips of young plants to encourage side shoot formation but I find the side shoots will develop in any event and winter root growth is preferred to shoot growth. Pinching out should be limited to the odd plant which fails to form side shoots at the same time as others;
* Do not forget to keep your plants moist if the weather is dry; they are more frost tolerant if kept moist than if kept dry.
Early flowering varieties:
In the UK, these are normally grown commercially in a heated greenhouse to flower from February onwards. This is achieved by sowing in August or September. The can also be grown in an unheated greenhouse by sowing in October / November to flower from April onwards.
Sowing overseas:
As we send seeds throughout the world, detailed guidance cannot be given for all climates. The above guidance can be considered appropriate for growers in the equivalent of USDA hardiness zone 6 or warmer.
Other Lathyrus species:
Most annual Lathyrus species are better sown in Spring and planted outside when large enough but L. chloranthus and L. paranensis should be Autumn sown as with Sweet Peas. Perennial Lathyrus species can be sown at any time between February and September but a Spring sowing is preferred.

® Rootrainers are a registered trade mark of Ronaash Ltd.

RP July 2009