Is It Too Late to Plant Sweet Peas? (The Tips You Need)

close up of sweet pea seedlings

Sweet peas are some of the most beautiful and fragrant flowers, making them a great addition to any garden. But with all of the hustle and bustle of life, it’s easy to lose track of time and get a late start on these flowers. Luckily, all hope is not lost! 

As long as you get your sweet peas planted no later than April, it’s not too late for these attractive flowers. Make sure to harden off your seedlings, trellis your plants, deadhead any spent flowers, and keep the soil cool to give your sweet peas their best shot at thriving in a later season.

I’ll go over the ideal growing conditions for sweet peas and share some essential care tips to ensure you have a fabulous flower harvest. I’ll also share the latest date you should get your sweet peas in the ground based on your agricultural zone. 

Sweet pea growing conditions

If you’ve never grown sweet peas before, they can initially seem somewhat intimidating due to their planting needs. But once you become familiar with their growing conditions, you’ll quickly realize that they aren’t that difficult at all. 

Similar to edible peas, sweet peas prefer cooler temperatures and won’t tolerate summer heat. You’ll want to plant your sweet peas in the winter or early spring, depending on your agricultural zone.

If you live in an area with milder winters, plan to start sweet pea seeds indoors and transplant them outside after about a month or when the soil becomes workable. You’ll want to direct seed your sweet peas outside if you live in a colder climate. 

pack of sweet pea seedlings
Sweet peas are easy to start from seed and the seedlings are quick to take off once planted. I’ll have blooms in no time!

For most of us gardeners, waiting to plant seedlings outside until all risk of frost has passed is the norm. But, this is not the case for sweet peas. In fact, sweet peas should be direct seeded outside about 6 to 8 weeks before the last frost so they can establish themselves during the cool spring weather. 

Days to maturity

Sweet peas take about 14 to 21 days to germinate and will develop into beautiful, harvestable blooms by late spring or early summer. To reach full maturity takes about 75 to 90 days and as the weather warms up, sweet pea flower production will diminish.

Here’s a table to help you determine when your last planting day is based on your plant hardiness zone. If you’re unsure what zone you live in, check out the USDA Plant Hardiness Zone Map and use your zip code to check.

USDA Hardiness ZoneLast planting dateTentative harvest date
Zone 4April 1stJune 15th-June 30th
Zone 5March 20thJune 1st- June 15th
Zone 6March 10thMay 20th- June 4th
Zone 7 February 20thMay 1st- May 20th
Zone 8February 10thApril 20th- May 5th
Sweet pea planting and harvest dates by zone

Caring for your sweet peas

If you’re worried that you’re behind on planting your sweet peas, pay attention to these basic care tips to ensure that your sweet peas have the best chance of thriving this year. 

Hardening off

If you start your sweet peas inside, they will need to be hardened off before you can plant them outside. Hardening off means acclimating your plants to the outside world over a week or so to ease them into the outside temperatures and sunlight. 

If you skip this process, your seedlings may go into shock once you transplant them, which will affect their growth and potentially kill any weaker seedlings. Learn how to easily avoid this disaster in this article, 7 Ways To Minimize Transplant Shock In Seedlings

Trellising

One of the easiest ways to improve your sweet pea’s performance is to trellis them. Like many legumes, sweet peas are a vining plant and love to climb. You have lots of different options when it comes to the type of trellis you use.

I prefer to use plastic netting, like Hortonova, that I attach to T-posts using zip ties. This method offers a lot more flexibility in deciding where to plant my sweet peas and makes for easier clean-up when the flowers are done for the season.

Trellising your sweet peas also creates extra space to squeeze in another crop with companion planting. For example, you could plant a row of another spring crop such as lettuce or cold-hardy calendula at the base of the sweet peas. Once the weather warms up, clear the whole bed, and it’ll be ready to plant a fresh round of flowers or vegetables. 

Other popular methods include teepee trellises and fencing trellises. You might even try getting creative and building your own trellis system. 

Deadheading

Deadheading is the process of removing faded flowers from the plant. Removing the dead flower heads will encourage your sweet peas to send out new blooms instead of converting the old flowers to seed pods.

sweet pea flowers with seed pods (1)
Keeping these seed pods picked will promote new flowers to come on, prolonging the blooming period of these sweet peas.

Deadheading is so easy and quite enjoyable because I know it will result in a fresh flush of flowers. It’s as simple as picking the dead flower heads off with your fingers. Just be careful to not pull off a large piece of the vine at the same time. Try anchoring the vine with one hand and pulling the flowers off with the other to avoid trimming too much of the plant. 

Keeping the soil cool

Another way to prolong your sweet peas’ life is by ensuring the soil stays cool. As mentioned earlier, sweet peas prefer cooler weather, and by keeping the ground shaded, their roots stay cool. 

Mulching and companion planting are two methods you can use to keep soil temperatures low. Both methods shade the soil and help retain moisture. Wood chips make an excellent mulch, and some easy-growing companions to try are sweet alyssum or creeping jenny.

Choosing sweet pea varieties

If you’re a bit behind on getting your sweet peas out this year, try planting one of the varieties listed below. These varieties are heat tolerant and will give your sweet peas extra growing time in the warmer months.

  • Mammoth Choice Mix: 5-6 foot tall vines with blossoms in pastel shades for a romantic look. 
  • Painted Lady:  6-8 foot tall vines produce pink and white color-blocked flowers sure to attract hummingbirds. 
  • Old Spice Mix: 4-5 foot tall vines with soft pink and purple blooms. Very heat tolerant in warm climates.
  • Streamers Chocolate: 6-8 foot tall vines produce flowers in shades of mauve and plum streaked with white. A very unusual look for sweet peas. 

In Summary

Getting behind in planting happens to the best of us gardeners. But it’s crucial to get sweet peas in the ground before the warmer temperatures keep them from thriving. 

As long as you pay attention to the last possible planting date for your agricultural zone and consider growing heat-tolerant sweet pea varieties, you’re sure to have a fantastic sweet pea harvest this season.

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