Why bother with sweet peas?
Because nothing else smells like that. Vanilla, honey, a bit of orange peel, and a top note of "I have my life together." Sweet peas are the ultimate spring flex for people who plan ahead, which is why we sow them in the depths of winter while everyone else is doom-scrolling seed catalogues.
If you've been waiting for permission to start, here it is. Get your sweet peas in now and you'll be cutting armfuls by October.
When to sow sweet peas in New Zealand
In Auckland, June and July are perfect. Anywhere milder, sow now. Anywhere colder (lower South Island, central plateau), give them an autumn sowing or start in late winter under cover.
Sweet peas are tougher than they look. A bit of frost won't kill them, but a sopping cold puddle will. Drainage matters more than warmth.
The soaking debate
Some say soak. Some say don't. The breeder Dr Keith Hammett, whose seed you should be sowing, says skip it entirely for hand-harvested, fresh seed.
If you're using older supermarket seed with hard, dark coats, twelve hours in tepid water can help. Tepid, not hot. Twelve hours, not twenty-four. Soggy seeds rot if you forget them, so set a timer.
Fresh Hammett-grade seed goes straight into the soil block.
Sowing the seeds
Sweet peas have long roots. They want depth, not surface area. Use root trainers, toilet rolls stood on end in a tray, or a deep pot with two seeds per cell.
- Use a free-draining seed mix, not garden soil
- Push the seed 2cm deep
- Water once, then leave the lid off so they don't go mouldy
- Keep in a sheltered, bright spot, not a hot windowsill
Germination takes 10 to 14 days. Don't fuss.
Pinching out (the bit everyone skips)
This is where you become a sweet pea person instead of a sweet pea hoper. When your seedlings have three or four sets of leaves, pinch out the growing tip. Yes, the bit that looks healthy. Yes, with your nails.
Pinching forces the plant to throw multiple side shoots from the base, which means more stems, more flowers, longer vines. Skip it and you'll get one weedy stem and a vague sense of disappointment.
Planting out and support
When seedlings are 10 to 15cm tall and the worst of the wet has passed, get them into the ground. Sweet peas are hungry. Dig in well-rotted compost or sheep pellets before planting.
Set up your supports before you plant, not after. Bamboo wigwams, a teepee of manuka stakes, an obelisk, pea netting against a fence, all good. They climb by tendril, so anything they can grip works. Plant 15cm apart.
Feeding, watering, deadheading
Sweet peas are needy in the best way. Once they're climbing:
- Water deeply once or twice a week. Soggy is bad, dry is worse.
- Liquid feed fortnightly. Seaweed, fish emulsion, or a tomato food works.
- Mulch around the base to keep roots cool.
- Pick. Constantly. The more you cut, the more they flower. Stop picking and they go to seed and quit on you.
The varieties worth your time
If you can only pick one, go heritage. The scent is the entire point. Modern Spencer varieties have longer stems and frillier flowers, but trade away some of the perfume.
For NZ gardeners, head straight to Dr Keith Hammett's range out of Auckland. The country's most serious sweet pea breeder, with a catalogue that goes well beyond the supermarket basics.
Six picks worth hunting down:
- 'Almost Black'. The darkest sweet pea going. Very dark maroon/navy that reads almost black in low light. Vigorous grower.
- 'Piggy Sue'. A pink flush on a cream ground, young flowers opening as a soft picotee. Named after a pig rescued from farrowing stalls. Yes, really.
- 'Cold Steel'. Five to six well-spaced frilly Spencer flowers per stem, blue standards with white wings. A step closer to a true bicolour. Sow June through September.
- 'Blue Shift'. The shapeshifter. Opens pink/mauve and morphs through summer to brilliant blues and aquamarines as the flowers age.
- 'Chocolate Flake'. Reddish-brown striped flake. Brilliant in cut arrangements, and the only sweet pea named for chocoholics.
- 'Nimbus'. English-bred. The most dramatic striped sweet pea going, with markings only on the back of the standard petal and the top of the wings. Never fails to impress.
Whatever you sow, pick a packet that smells like something. The whole reason you grew them.
The honest bit
Sweet peas reward people who keep showing up. Sow now, pinch out, support well, pick often. Do all four and you'll have a vase full of October mornings before anyone else's tulips have made up their mind.
Welcome to the dirt cult. You'll never be normal about flowers again.
