How To Grow Sweet Peas

Sweet Peas are a delight to grow and have the ability to fill your garden (and your home!) with beautiful sweetly scented blooms in a variety of wonderful colours. They are very easy to grow with the most ordinary care yet will reward a little extra effort with even more wonderful results. Here we give some brief information to help you get the best from our favourite plants.

Sowing Sweet Pea Seeds
Whilst many insist that Autumn is the very best time for sowing sweet peas superb results can be had from spring sowing – sweet peas can even be direct sown in their final position as late as early April. It is probably true to say, however, that the finest exhibition quality sweet pea blooms come from October sowings as these plants have the best possible root systems. Sow into 4 to 6in pots using a good quality free draining compost - John Innes No 1 gives good results - making sure that the compost is moist and free from lumps. A 4in pot will accommodate about 7 seeds and a 6in pot up to double this quantity. Sow at a depth of about 1in, firm gently and water well.

Growing On
Autumn sown sweet pea plants should be allowed to grow slowly and steadily to form an extensive root system with relatively little top growth. The best place to grow on is a cold frame or even a sheltered spot outside. Keep the pots moist ensuring that the compost does not become dry at the bottom. Do not be tempted to over water as the developing plants will not thrive in waterlogged conditions. Feed occasionally with a liquid feed using special sweet pea fertiliser or tomato feed if you cannot obtain it. If sowing takes place in the spring take care to keep the plants cool (but frost free) to allow steady root growth and pay particular attention to watering. Mice can be a particular hazard as they can dig up and eat germinating sweet pea seeds and they should be guarded against and pigeons should be kept away from outdoor sowings.

Autumn sowings produce sweet pea plants that have developed quite slowly over several months and usually break (develop side shoots) quite naturally without the need to pinch out. With more rapid growing spring sowings however pinching out is vital to encourage breaks and this should be done by removing the growing tip once three or four pairs of leaves have opened Whether planting in autumn or spring, the aim is to produce a short stocky plant about 4-6in tall by planting out time.

Planting Out
Sweet Peas like on open sunny position and thrive in moist fertile well drained soil. All but the dwarf kinds will also need a system of support to encourage their climbing habit. The planting ground should be dug over well beforehand and well rotted manure or garden compost incorporated, as this will provide additional nutrients and aid moisture retention. Prior to planting the soil should be cultivated again so that it is friable and free from large lumps and some fertiliser incorporated - Growmore or similar at about 2oz per square yard is fine. Now is the time to erect the support system and a number of methods are possible. Posts and wire, canes and twine or netting all provide good support for the developing plants and a number of proprietary systems are available. Plant at the base of the support by making a hole with a trowel and firming in afterwards. (Sweet Pea plants grown in pots should have the root ball loosened to separate the plants somewhat.) Give the newly planted sweet peas a good watering.

After Planting
If all you want is a fine display in the garden the sweet peas can be left pretty much to do their own thing! It may be a week or so before any real progress is seen but soon the plants will begin to climb and may need a little help at first to guide them in the right direction. Keep the plants well watered and feed every couple of weeks with a liquid tomato feed. As flowers start to appear it is vital to either pick them for the house or remove them as soon as they start to fade. If this is not done seed pods will develop and the presence of these greatly reduces the appearance of subsequent blooms. Regular picking, together with generous provision of food and water, will give the most prolonged and colourful display.

Growing Sweet Peas For Exhibition
This is very much a subject in itself but the main principle is to achieve the strongest, most vigorous plants and then to encourage them to devote their energies to producing fewer, yet larger, high quality flower stems. Autumn sowing is virtually a must as this gives the most developed roots and enables the earliest planting in the garden. Thereafter all but the strongest stem is usually removed which is then nurtured. Tendrils can be removed so that they do not sap the plant's strength and the growing plant is tied into the support using wires or raffia. The resulting flower stems should be longer and stronger and the number, size and quality of blooms per stem will be maximised.

Further Reading
Of the available books on sweet peas, we have found the following to be particularly useful. Enjoy Sweet Peas published by The National Sweet Pea Society – an authoritative guide to cultivation of sweet peas written by experts and packed with good advice. The Sweet Pea Book by Graham Rice (Batsford) A recent and comprehensive volume from an internationally acknowledged authority on flowering plants. Good descriptions of hundreds of varieties and much more in depth information.

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