How to Grow Sweet Peas in Your Garden

How to grow Sweet Peas in your garden.  Their sweet perfume is a delight that cannot be surpassed.  I grow them all through the Summer but I get started early in Spring from seeds.

How to plant Sweet Peas in your garden one easy step at a time. Growing these fragrant flowers is easier than you think. And if you choose the right ones and use a few tricks, you can grow them on through the summer.

Note: These are the annual type and not the perennial. Perennial Sweet Peas are not fragrant and can become horribly invasive in some areas.

I started my love affair with Sweet Peas back in 1988 when I lived in the San Joaquin Valley of California which has completely different growing conditions than here in my mountain garden.

Why am I telling you this?

Because it shows how Sweet Peas can be grown in completely different conditions and still be gorgeous.

pink sweet pea blooms

My Zone

We live in USDA Zone 8 with snowy winters and dry Summers.
In Zones 7 and above where winters are milder than in other areas of the country you may be able to sow Sweet Pea seeds in the Fall, around October but in other zones it is best to wait until late winter/ early Spring about 6 weeks before your last frost date.

I currently live in zone 8 and I have had Sweet Peas reseed themselves in Fall and sprout and still winter over to bloom in Spring but I have also endured late hard freezes that killed all my Sweet Peas in one fell swoop.

To be on the safe side start half of your Sweet Peas seeds early in February or March and save some to start later on, just in case.

Related: All about Garden Zones and why they are relative

How to Plant Sweet Peas Early

Sweet Pea seeds look like hard little peas but turn into the sweetest scented blooms you have ever smelled.

sweet pea seeds in a hand

Some will tell you to nick or soak your sweet pea seeds overnight before sowing and after 20+ years of growing them, I can tell you to skip this step. It has not helped at all and if you still decide to soak, do NOT leave them in the water longer than 8 hours. They will rot very quickly.

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Here is an example of how easy they can germinate, I found this little pea shoot starting from a seed I dropped accidentally in a pot next to a Sempervivum.
It sprouted while sitting on top of the soil , there was enough moisture without soaking.   I used an arrow to show you, it kind of blends in.

Somewhere along the line this past Fall I dropped a seed and it sprouted where it landed.   We have had a brief warm spell this month and I suppose it thought it was a good time to sprout!

When to Start your Sweet Pea Seeds

February is a good time for me to get Sweet Peas started in my greenhouse, many other places March is an excellent time to start. (Please Note: once it warms up outside I sow them directly in the ground) They prefer soil temps of 50 to 60 degrees so you may need to shade the area if it has already warmed up. Check your last frost dates. Since sweet peas can germinate quickly and grow you don’t want to start too early as they do better if planted out in the garden when they are shorter and before the roots get too far.

If you live in warmer zones you can start yours in Fall. Wherever you live, start your sweet peas when it is cooler.

Starting indoors

I use regular potting soil or compost and 3 or 4 inch pots.  (taller pots work better as the roots get long but I have used these smaller pots with success)

Fill your pots with soil, not to the brim, you want room to water.  Poke the seeds in about half an inch. I put in 2 seeds per pot but some like to space their sweet peas further apart in the garden so you can plant just one seed per pot. (Some prefer using peat pots or poo pots so as not to disturb the roots when transplanting out in the garden)

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Don’t press the soil hard, just firm them in.  Water the seeds in and that will help tamp the soil down.

If you live in a very cold area and are starting early, place the pots in a warm spot indoors, but not on a heat mat. Sweet peas like soil temps on the cooler side.

Pinching

When seedlings are about 4 to 6 inches tall pinch out the central stem just above a leaf joint, leaving about 2 or 3 leaf nodes,  this will promote branching.

These below need pinching back.

You can snip them back to with pruners or just use your fingernail.

These are the seeds I potted up today.  High Scent is a very fragrant variety and well worth growing. I love them as much as the Anniversary Sweet Peas.

High Scent Sweet Pea
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A great selection for heat tolerance is the Old Spice Blend.
 I grew some of these by my greenhouse in a barrel alongside a rose and they did just fine even though it gets quite hot in this spot.  Here you can see they have reseeded themselves.

They are a little beat up as the snow has been covering them for weeks and more snow is on its way but once warm weather is here for good they will get strong and crawl up the trellis.

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I stopped cutting my Sweet Peas in September so they could go to seed and replant themselves and I collect some to pot up in the greenhouse.

A great variety just for cutting is Fairy Tale Blend. They have long stems great for floral arrangements but pick  from all of your Sweet Peas.

How to Grow Sweet Peas and get fragrant flowers to pick all summer long. FlowerPatchFarmhouse.com

Keep Them Growing All Summer Long

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Cutting the Sweet Peas frequently, every 9-10 days will get continuous bloom all Summer long.  If you don’t cut they will go to seed and that is it for the plant, no more blooms. This is especially important when it gets hot and dry.

I keep a soaker hose at the feet of my sweet peas for consistent watering, we don’t get summer rains.
Adequate water is one key to success when you grow Sweet Peas. A good mulch around the base of the sweet peas helps to keep moisture in the soil be more consistent.

Grow Sweet Peas in full sun with some afternoon shade, if you can.  Where it is very hot, afternoon shade will help them survive the hotter months. They may take a brief rest from blooming but don’t despair, once the heat subsides a bit they will start to bloom better than ever.

Plant where the soil is rich and has good drainage or amend to make it so.  They don’t like soggy feet.  (for a post on how I keep my soil rich and loose see my Lazy Gal Garden guide)

Provide Support

Be sure to provide support, these can climb well above 6 feet and will wrap themselves around whatever they need to go up!  I planted some seeds in one of my pots of Bamboo, they will be happy as clams clamoring up the canes and I will enjoy their lovely perfume on my back deck all summer.

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Disease

Sweet Peas are susceptible to powdery mildew. This doesn’t really do much harm to mine and I just keep picking the flowers, and many times the mildew disappears.  Good air circulation is key to keeping the mildew at bay and a healthy well fed plant helps it to fight through it.  As I stated before we have dry summers, very little humidity, you may find you have to battle mildew more if you grow sweet peas in a humid environment.

Feed, feed, feed

Sweet Peas are heavy feeders so be sure to fertilize.  A good soil drenching with a diluted organic liquid fertilizer every week should be good.  A blend of fish emulsion and liquid kelp is highly recommended but I have used worm casting tea as well with success.

Aphids love Sweet Peas too but since I garden organically I have a large amount of Lady Beetles that live here so they take care of them for me.  If they get out of hand I do spray the Aphids off with my water hose.

Pink Sweet Pea


Plant your seedlings out in the garden around the time of your last frost.  Set them about 4 to 8 inches apart and close to a trellis or support.  You may have to tie them up depending on the type of support.  I grow sweet peas by a cattle panel trellis and I just wind them up it as they grow.  If I get more than one coming up in my pots I just plant them all together.

Here is a video with more info on growing sweet peas you will enjoy!

sweet peas and pamela groppe with video play button overlay

Have you tried Sweet Peas in your garden?

More garden articles you may enjoy:
How to Grow Delphiniums from Seed
How to Start Roses from Cuttings
How to Propagate Zonal Geraniums

I wish you Happy Gardening!

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18 Comments

  1. I had no idea there was an annual and perennial version. I always pick the perennial type that grown wild in my neck of the woods and they smell very sweet. Thanks for the info today, I learned something new:)

    1. Then they could be a different variety of perennial Sweet Pea. The seed catalogs that I have seen that carry the perennial sweet pea all state that they have no scent and I know the ones that have gone wild around here don’t either. You might have a new variety there!

  2. One of my favorite scents in the garden!! So looking forward to spring, summer and blooms!
    ~Chris

    1. I am looking forward to them as well. We hope to get a bit more rain and snow to help with the drought but this next week looks sunny, clear and warm. I love warm but I am also aware of the need for more precipitation. But I can’t control the weather so I will enjoy whatever we get. 🙂

  3. I also never knew there were annual and perrenial. By the way what city do you live in in the sierra mountains? Looks beautiful and we have been all over the Sierras. Was just wondering.

    1. We live near Arnold on Hwy 4. If you have come this way in summer you may have noticed the sweet peas lining roads, those are the invasive perennials that nearly everyone here hates because they are so misbehaved. 🙂

      1. Pam, those are they kind I had in my backyard….I kept them contained by pulling up those that rambled on the ground and attended to the one’s that grew up a trellis.

        1. Many do manage them just fine, and I know many plants that are invasive in one area are not in another. Around here they are hated as the seeds get carried by birds and they are overrunning in so many areas. Since the perennials ones do not have the sweet scent of the annuals I prefer growing for scent and they thrive here without become plant bullies. The perennials can be so pretty too though.

    1. Not necessarily. I have some that sprouted this Fall that I have left to their own devices. If they make it they will be early bloomers, if they don’t then they will be cut back in Spring. Trimming would not hurt them at all, and may encourage more branching for a fuller plant.
      I don’t know your climate but they could be killed out by severe cold. No worries there, just re-plant seeds come Spring. Or you can start some indoors to set out. I have much more success in seeding in place rather than starting indoors and setting out plants.
      Hope this helps.

  4. I read in your posting you were planning to grow sweet peas in hanging pots. Any luck with that?

    1. I failed to do that this year. I think the Knee Highs would work best as they don’t grow as long as my heirlooms. But the ones by my back door are in pots with the bamboo and it is perfect pairing, the bamboo supports the climbing sweet peas. I ended up buying large handing petunia pots instead of planting my own this year, I got them from a wholesaler for such a cheap price that I could not pass up the deal.
      I should still try it though and see how it works. Now to find those Knee Hi sweetpea seeds!

  5. I, too have perennial sweet peas and they are almost over the top fragrant. I love them, they make such easy and beautiful cut flowers for the home. Thanks for your post, very “sweet.”!

  6. The annual sweet peas are easy to control, just cut them before they go to seed. Since I use mine as cut flowers that is not hard. Now the perennial sweet peas are invasive and quite the pest as they spread by rhizomes and not just seeds. I am the only one that does a thing in our gardens and I have to replant the annual sweet peas each year, rarely do they come back on there own. It also depends on growing zone, what is invasive in one area is not in another so you must get familiar with what will become a rampant monster in your personal garden area and garden accordingly.

    1. I hear ya, I am right now trying to edit and make things less time consuming. I would love some help in the garden and that nursery with the landscape artist sounds wonderful. I really don’t have a large area but I do need to put in some more herbaceous perennials that take less care than the seed grown annual/biennial type that reseed themselves. I am heading a new direction for where I want to spend my time and it brings me as much delight as the garden. I would like to travel a bit more in the summer as well so it really takes some soul searching as to where to edit and reduce. Finding out what is locally a pest is important, I love morning glories but I know that a few states have banned them because they have gotten out of control, here they are not at all a problem.

  7. How do I convert, your to do schedule from zone 7 to my zone 9b.

    Possible a book or garden calendar for zone

    Thank you
    Jan

    1. I am not sure of what you mean exactly but for Sweet Peas you can start them now in your zone. Even though the zip code may come up as 9b things can affect what and how you grow because of a micro-climate in your garden. Lots of shade? All sun all the time? Back side of a mountain or hill where you get lots of wind?

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