Growing Sweet Peas – the basics

(Applies to all types of Sweet Peas not just Spencers)

By Alec Cave

Seed selection

If planning a select colour scheme named varieties in fixed colours can be obtained from most of the seed firms advertised in the Sweet Pea Annual – also mixed packets of seeds are available.


The site for growing any of  the Lathyrus species must  be  in a sunny position.   If there is not enough sunlight the flower buds will not form; a position, preferably facing south is  perfect and ensure they are protected from prevailing winds.

Sweet Peas can be grown in clumps of twelve plants in a herbaceous border, placing some at the rear of the border and some nearer the front to act as a nice foil for the other  plants.

If you are lucky enough to have a vegetable garden a nice row of Sweet Peas grown up pea sticks or canes is far better than a hedge and you can get the benefit of all the cut flowers too.  They can also be grown in containers, but to be successful these should  be a minimum of 18 inches deep – this is so that they do not dry out too easily.  The containers are best filled with John Innes No 3 compost.  As the containers fill with roots the nutrients will be washed out of the soil so feeding with maxicrop is advisable.

Ground preparation

On heavy clay soil fork the ground  over incorporating some well rotted manure, leaf mould or compost and coarse gravel to improve drainage.

On light sandy soil incorporate some well rotted manure, leaf mould or compost, to keep the soil together and retain moisture.

Seed sowing

Seeds can be sown in small trays or 5 inch pots in March.  Fill pots with multi-purpose compost up to one inch (2.5cm) from the pot rim.  Firm compost by placing one pot inside the other and don’t forget to water the pots with a fine rose on your watering can.  Place about 20 to 30 seeds on compost and top up to 0.5 inch from the pot top  – place on a sunny warm windowsill or in a greenhouse and cover the pots with newspaper to stop them drying out. After about seven to ten days the seeds will start to germinate.  When one inch (2.5cm) tall knock them out and pot on into three and half inch pots using multi-purpose compost.  Place plants in cold frames and water in.  If no frames or greenhouse is available place the pots under a south facing wall, hedge or fence and cover with fleece to protect against frost.  Gradually harden the plants off.  After two pairs of leaves have formed remove the growing tip.  This will encourage plants to make new shoots from the base of the plants.  When the plants have made sufficient root they will be ready to plants out.

Some people prefer to sow seeds directly into the ground in April when the ground has warmed up sufficiently.  If doing this prepare the ground as usual, erect sticks or canes and at the base of the sticks remove a 4 inch groove of soil.  Replace this with multi-purpose compost and sow seeds 2 inches apart, about 1 inch deep around sticks and water in with a fine rose. When plants have produced their first two pairs of leaves remove growing tips.

Planting out

Before  planting  out the ground  should be firmed  by treading all over it to consolidate it and help retain moisture in growing season.  A dressing of fish, bone and blood should be lightly rake in at 3 ozs per square yard.  It is better to prepare ground and then erect sticks, canes, netting before planting.  If planting out in wet conditions or on heavy clay ground buy the cheapest compost available from a garden centre.  Spread this on the surface and plant into  it.  This will give the plants a good start - plant about 6 inches apart.


On a herbaceous border or annual border peas sticks are the best method of staking. If these are not readily available place garden canes about 20 inches apart and secure pea netting to these canes.  The canes need to be at least 6 feet tall.  Make sure you tie the first shorts to the netting to start them climbing.  After planting it is a good idea to give plants a light dressing of slug bait.  If you are growing organically a good idea is to put some sharp gravel around plants or use crushed egg shells.  This will act as a good deterrent.

Dead heading

This  is most important.  The more you cut the flowers the better the plants will perform.  Do not let seed pods mature as this will make the plants think it has done its duty by flowering, making seeds and dying.


Regular feeding at weekly intervals will prove beneficial.  I like to use Maxicrop as a foliar feed.  Mix in a watering can and spray on the Sweet Pea foliage just below the flowers.  This  is a good deterrent against aphids.  Feeding should be done morning or evening avoiding strong sunshine.


In very hot weather and dry conditions plants benefit from watering and spraying over with water.  This will keep the plants plump and in good conditions.

Cutting flowers

Always make sure plants are not dry at roots before cutting as if they are the flowers will go over very soon.

Pests and diseases

Luckily Sweet Peas do not suffer from many pests and diseases.  About the only pest to attack Sweet Peas is aphids.  These appear mainly after a dry spell when plants are under stress.  Aphids can be dealt with by spraying with S.B.Plant Invigorator.  This is a new non poisonous organic spray which also acts as a foliar feed.  It also kills red spider mite and whitefly. 

I  hope this helps with how to grow a few plants in the garden for cutting.

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© Roger Parsons