Sweet Pea Growing Guide
Sweet Peas are one of my favorite flowers to grow. From early spring flowering all the way through the beginnings of dahlia season. Once you figure out a few small tricks, they are easy to grow and have an amazing variation of colors, stem lengths and of course their amazing scents.
Serenity
I think the most confusing thing when starting your seed and growing your sweet peas is the confusion you will find with multiple growing methods you read. As time has gone buy and using a lot of trial-and-error growing methods have been updated so some methods that have been tried and true in the past are no longer used. I will go over a couple different ways to grow your sweet peas with explanations on ”why ” that will hopefully give you success in your garden.
First: It’s not necessary to chip, scrap or soak your seeds. In the past it was recommended because the seed outer casing was a lot tougher than it is today. Unless your package specifically states to soak or scrape your seeds its no longer necessary or recommended. Seed casings are not a hard as they use to be and if you soak or scrape you run a bigger risk to rot and a lower germination rate. The first year I wanted to grow sweet peas on a larger scale, I thought I was super smart and I soaked all my seeds, then I thought I was even smarter and tried starting my seeds in 2”soil blocks. Well, my rot was through the roof and my germination rate was so low that I was only able to grow enough seed for me to try again the following year.
Second: I have found success using a 4” pot or a 50 cell tray that are 3.5” deep. If using a 4” pot you can sew several seeds in the one pot but you will eventually have to transfer into a cell tray. You won’t have any empty holes from seeds not sprouting. The thing you want to remember is sweet peas are profuse root growers and the longer you leave them in the 4 “ pot, the bigger chance you have of the roots tangling. I don’t advise to go buy a bunch of 50 cell deep trays if you’re not wanting to grow on a large scale, I recommend using the 4 inch pot with about 10 seeds or so per pot and just use caution when separating to plant out. Sweet peas are actually pretty tough and handle being separated really well. If you plan on transplanting into cell trays you can actually start up to 20 or so seeds per 4” and transfer into a cell tray when seedlings are about and inch tall and first leaves have a little curl to them.
Third: Time to start sowing. Once you have picked your pot, it’s time for the soil. Sweet peas really aren’t that picky, but do prefer good draining soil with a nice compost base. It’s not necessary to run your soil through a strainer or sifter to get the larger chunks out if that is something you are use to do for starting your seeds. Soil needs to be slightly damp and seeds need to be planted about 1/2” deep. I use the eraser side of a pencil and give it a good guess, plop the seed, cover and give it a light watering or a heavy misting. Set aside is a cool dark area and wait for things to grow. It’s that easy. NO heat mat, NO lights, and NO humidity dome. You should start seeing life in about a week or so, but don’t be surprised if it takes up to two weeks. Once you see green poke their head out of the soil it’s time to move them to cooler temperatures. If you don’t move them to cooler temps they really start taking off . They are looking for light and will really start stretching. One of the mistakes I made was putting more than one variety in a 50 cell tray. Different varieties have different sprouting rates. When I put two different varieties in one tray, half the tray sprouted in about a week and the other took almost two weeks. The side that sprouted on day 7 is starting to get leggy by the time the second variety is starting to show. That is where sowing each variety in a 4 inch pot would have been beneficial.
I move mine to my unheated greenhouse but be careful on a nice sunny winter day it can get rather warm in there and they will shoot up like nobody’s business. I also have run into that. What I generally do is set of a table just outside my greenhouse, that way in cases of sever weather I can get them move inside, but in general sweet peas really like it cold and if you find that yours are froze solid one day, just ignore them, as they warm it they will be fine.
Now is the time to let them grow nice and slow to develop a strong root structure. Slow and steady wins the race as they grow their tap root, it’s beneficial to have short, strong greenery.
What do you do if the stems shoot up and get real leggy? Don’t panic, sweet peas are resilient, chances are they got to warm, do what you can to get them to cooler temps and try not to do too much to disturb them. Unless the stem is so long that it folds over and breaks, don’t pinch. They will recover it will just be a little more difficult when it comes time to plant out. They will have a tendency to tangle so from this point on out, handle with care. If they have a few sets of leaves when you plant out you can cut those tops out (also known as pinching). If you forgot or not quite sure if you want to. It’s not necessary to pinch, you will still have a beautiful trellised sweet pea vine that will give you lots of amazing flowers.
Late winter or early spring is when you can plant out. Just make sure you can work the ground. They love a rich well draining soil with lots of compost. Now it’s time to wait and watch them grow. Be sure to fertilize on a regular basis. They are heavy feeders and like cool roots as the weather gets warmer so don’t forget to water these guys or they crap out before you know it.
Sweet peas can also be directly sewn into the ground as soon as the ground is workable. I don’t do this. We have a lo t of critters that enjoy sweet pea seed. For some reason it’s toxic to people and be careful around pets but wild animals and birds seem to tolerate them just fine and will clean me out.
If you do prefer to direct sew in zones 7 and higher, they can actually be sewn in the fall.