Sowing hardy annuals - sweet peas

Sowing Hardy Annuals - Sweet Peas

Sweet peas are one of the most popular seeds to grow. The scent, and being able to pick a bunch every couple of days to bring into the house, is so rewarding. I've got mine through the borders on obelisks and also grow them in the vegetable garden.

There are lots of varieties to choose from – which you grow is down to you and the colours you're drawn to.

• One I always grow is 'Cupani', which has smaller flowers than some modern varieties but is one of the sweetest-smelling sweet peas you can grow.
• This year I'm also growing 'Prince of Orange' and 'Lord Nelson'.

I always use root trainers for sowing my sweet peas. These allow a long root to run and open out like a book when it's time to plant out. I re-use the same ones year after year.

Sweet peas germinate quickly and grow fast so can still be sown until the end of March. They can also be sown in autumn for a head start; they are quite hardy once they get going; if they're still tiny you can overwinter them in a frost-free greenhouse.

How to Sow Sweet Peas

1. Clip the root trainer 'book' together and fill up the compartments like a modular seed tray, shaking the compost down.
2. Stand the 'book' in the root trainer tray and repeat for as many 'books' as you need.
3. Water the compost using a watering can with fine rose.
4. Sow one or two seeds per compartment, gently pushing the seed about 1cm into the compost and lightly covering over.

Pinching Out

Once your seedlings have germinated, avoid leaving them in the warm for too long or they will get spindly.

To make your plants stronger and sturdier, pinch out the tops of the seedlings to encourage them to branch out.

• Once the seedling has two pairs of leaves, use scissors or finger and thumb to snip or pinch out the growing tip. It feels destructive, but it's really worth doing to create bushier plants.

Hardening Off

The seeds I sowed in mid-February, I will plant out around mid-April to end of April.

Before you plant out sweet peas, they need to be hardened off. This means getting your young plants acclimatised to outdoor weather.

• For at least a couple of weeks before planting, put them outside during the day and bring them back inside (or into the greenhouse) at night. I'll start this in early April.
• Eventually, leave them outside continually for about a week in their pots or root trainers before planting, to avoid any shock.

Planting Out

There are three things you'll need to remember when planting out your sweet peas.

1. Soil: sweet peas like a really rich and moisture-retentive soil, so make sure to incorporate plenty of homemade compost or manure into the soil when planting.
2. Support: sweet peas need support but they climb using tendrils, which cling onto small twiggy things.

• This means bamboo on its own doesn't work that well, as it's quite slippery.
• If you're using a bamboo wigwam, put string or some twigs such as pea sticks around the outside so the tendrils can cling on.

1. Water: give your sweet peas a really good water after planting and continue to water them regularly while they establish.

Planting out your sweet peas at staggered times will help to ensure you have a succession of flowers to pick throughout June, July and August.