Growing Sweet Peas by Jim McDonald


My soil is alkaline with a Ph of 6.5 to 7.0, approx. 400mm deep on top of chalk. It is hungry soil and requires a lot of additives to:

  1. Retain moisture
  2. Give roots food to grow
  3. Allow roots to spread with ease

Before I start to put the spade into the ground like to remove all weeds that are likely to seed or send out roots to spread next season. Ail grasses can be dug in.


For a double row of cordon grown sweet peas take out a trench approx. 600mm (2ft) wide by the depth of a spade. Into the trench put one bag of farmyard compost i.e. cow or horse manure or 1 barrowful of garden compost. To every metre run add 20z of Vitax Q4 fertilizer, dig this into the bottom of the trench. Back fill the trench. Leave the ground surface as rain and frost will break it down during the winter. I normally prepare the trenches from November to January. If you do this too early the winter rain will leach out the goodness you have put into the trench ready for the piants In the spring. Three weeks before planting out apply 20z Vitax Q4, 20z Sulphate of Potash, 202 chicken pellets per square metre.

BUSH GROWN — For a wigwam take out a circle approx. 750mm diameter, one spade depth — proceed as for a trench. Place 12 canes approx. 200mm apart and then use a 400mm diameter plastic plant support at top of wigwam. For getting more flowers use this method as you are letting all side shoots grow and flower. To stop the tendrils at the end of the leaves clinging onto the flower stems and bending them, every week go around with a pair of scissors and remove the tendrils.

Recap Fertilizers at ground preparation time

  1. Vitax Q4— good for the plants, it is organic with trace elements and the plants will use as and when they want.
  2. Three weeks before planting out use 20z Vitax Q4, 20z Sulphate of Potash, 20z chicken pellets per square metre.

PROPAGATION • Sowing seeds from October to March. Three sowings.

Items required – Plastic box, kitchen paper, seeds, labels

Take a plastic box, place damp (not soaking wet) kitchen roll (three sheets) into the bottom of the box, put seeds onto paper, cover with another sheet of damp kitchen roll and replace lid (put label on box to identify variety). Keep inside (like airing cupboard)

To make up compost for growing on use multi-purpose compost e.g. Jacks Magic or peat compost with John Innes added. Add Perlite — 1 part Perlite to 4 parts compost. Perlite keeps the compost open and will protect from frosts. Fill pots, bags or root trainers with compost.

Seeds — check the boxes each day. The seeds will swell and then send out a white shoot. When you see the white shoots on every seed, plant into pots —2 seeds per 75mm pot or bag. Plant seeds 12mm below the surface. When you complete a variety put a label into the pot. Keep varieties in individual trays to avoid mixing up.

Put tray in greenhouse or on window sill of a cool room (no heat required). Put newspaper on top of pots to keep out light. Check daily, when the first white crook appears remove paper.


Do not over water pots or feed the plants but keep the pots reasonably dry as too much moisture will damp off the plants.

When the plants have grown on and produced two pairs of leaves, pinch out the top of the plant to enable the plant to send out side shoots (these will be your flowering shoots later on) and then put in open cold frame.

Only cover when there is heavy rain or hard frost or snow.

End of February — water on a feed of Miracle Grow, half strength every 2 weeks.


First sowing — in early November for flowers in third week in May. Keep cutting flowers and DO NOT allow them to go to seed as they will then flower well in to July. To have a succession of flowers sow again in early January — flowers mid June to August. A third sowing end of January will give you flowers end June to early September. These timings are subject to suitable weather conditions i.e. not cold, excessive rain and excessive heat.

SOIL PREPARATION READY FOR PLANTING From the time of preparing trenches in November to January, to early March, the ground will have had a lot of rain and frosts. This will break down any rough area of soil. From early March until planting time I rake and level out the top few inches to get a nice fine tilth. Work in extra Vitax Q4, Sulphate of Potash, chicken pellets (about 20z to the square metre or yard).

PLANTING. TO GROW ON CORDONS Set out the row over the trench with a line either side, approx. 500mm apart. Have a rod with markings 175mm (7″) centres. Place a cane on every mark. You can also have a single row of canes. Try to have the rows running east to west. Link the canes with a wire either 1.20m (4ft up the cane) or at the top of.the cane. Then fix the cane to the wire.

PLANTING OUT Check that the plants are healthy and strong, they have been stopped and have at least one strong side shoot, two is better but not necessary. Remove from the pot and check a) the roots are filling the pot, b) they are white c)move compost from around the neck to check to see that they are white, if brown this is a sign of “brown collar”, disregard the plant as it will not survive. Form a hole the size of the pot or root trainer’s size and depth. For a pot with two plants, form hole between two canes (inside the line of the canes). For a pot with one plant, form hole on inside of cane. Place plant Into hole down to level as in the pot, back fill and gently firm soil around the plants. If plants are more than 100mm (4″) high tie them loosely to the cane for support. Below this height, leave. Leave plants for cordon growing for 4 to 6 weeks depending on the growing season. Wigwam, keep plants tied to canes every 150mm. Don’t thin out to one plant as this checks the growth at start.

CORDONS after 4 to 6 weeks reduce side shoots on each plant to one, this being the strongest, which may not be the longest. Remove all other side shoots. Ring or tape the side shoot to the cane, every 150mm. At the height of the growing season plants will grow 300mm (12″) every week.

STRENGTH TO TOP OF PLANT whenringing or taping the plant to the cane always remove the tendril from the end of the leaves, also remove side shoots from the axil of the leaf. This will allow all the strength to go to the head of the plant and form the flowers.

FEEDING When plants are 1 metre high start to feed with Tomorlte and Miracle Grow, half the recommended strength. Water Tomorite into the roots, water Miracle Grow over the plants. One week Tomorite, next week Miracle Grow. Water in the evening.


Slugs use slug pellets, the type safe to use if you have cats and dogs.

Greenfly and caterpillars For pest control use a systemic insecticide. Spray in the evening, not during the day as this will scorch the leaves. In the evening the plants will take up the fluidduring the night. Greenfly, if not controlled will damage the plant and it will be infected with a virus and the flowers will have a mosaic appearance. Remove plant and burn.

Pollen beetle — little black beetles get into the keel of the flowers. They don!t do any damage. Cut flowers in the evening and place in greenhouse or shed by a window and by the morning they will have left the flowers. Bird damage — Tits and sparrows will eat the greenfly and pollen beetles but damage the flowers in the process.

WATERING Do not let plants dry out.


6ft, 7ft, or 8ft canes

Rings, string, raffia for holding plants to canes.

Tomorite, Miracle Grow

Slug pellets

Systemic Insecticides for greenfly

Systemic Insecticides for greenfly