When to sow:

Again, this depends on whether you want beefy, exhibition level sweet pea blooms. If this is the case, the answer is easy. Sow a Spencer in late October or early November, grow it on hard, plant it out on the last day of February, feed it, and it will flower its socks off when the day length gets to the right level (no-one seems to know exactly what this is, but it roughly translates into the end of May, early June if you are in the UK).

I am not growing for show; I am growing for my bedside table, possibly a supper party, and for the scent. And so, this is my sweet pea schedule.

Like so many of the best flowers, sow little and sow often. The flowering season of each plant can be stretched a bit with diligent picking, cooler weather, and the odd decent feed, but generally, I would suggest some good old successional sowing. My sowing schedule goes something like:

The first sow -

October, at about the time the fire gets lit for the first time, as this is a good sign that the nights are cold, and the house is warm. The seed and their compost goes in a warm place but as soon as they are up and sprouting, they go outside to a cold greenhouse or a cold frame.

The Festive sow -

As soon as the in-laws have left, I am in need for a little solitude and solace. I am also unlikely to be using the cooker for a few days as the fridge is full of leftovers and I have already eaten my bodyweight in sprouts and bread sauce. The lid of the Aga is therefore available for providing the sweet peas with a little bottom heat. As above, once they are up, out they go.

The February one that I generally forget:

This one is more a nice to have than an essential, and the chances are the previous sowings are already looking strong and healthy and I am already worrying that I am going to run out of space in the greenhouse. However, it is good to plan for this one because of mice. There is little than can go wrong with germinating and growing sweet peas (they are endlessly straightforward generally) but the one thing that can catch you out is mice. I used to think that, once the seeds had germinated and the goodness gone from the seed into the shooting growth, the mice would lose interest. However, I don’t know if they were especially hungry last year, but I saw enough horror stories of ravaged seedlings to not be so confident in the future. If you have suffered sad losses from the previous two sowings, February is a good time to regroup and try again.

The last gasp

I frequently have sweet peas going into September. Partly because I grow a lot of sweet pea plants, and partly because I cannot resist a May sowing. I have got all my annuals done and my seed sowing fingers are itching. One last throw of the sweet pea dice. Just a few. Just because they look extra special amongst mists and heavy dews. Oh ok, I just do it to show off really.

You may have noticed that, even in the most fecund stage of spring, I never suggested direct sowing. You are, in my experience, simply feeding mice very expensive food if you do that. I always start mine indoors and keep them protected.

Starting sweet peas from seed

You will need:

·    Peat-free compost. Not the seed compost, a good multi-purpose.

·    Cardboard inners or, if you are going to reuse, good quality plastic root trainers.

·    A container to hold the inners, one of those plastic trays that mushrooms come in is perfect

·    Labels

·    Seed

There is also a bit of a debate about pre-soaking seeds before sowing and, like so many of these gardening dichotomies, it inspires strong feelings in some. Not in me, I hold a pragmatic view. If the seed is over a year old and looks a bit wrinkled, soak it. If they are plump and look smooth and round, they probably don’t need it. The initial watering will suffice.

Fill your pots with good quality compost. Sweet peas produce tap roots, so they do need a bit of depth underneath them. This is why cardboard tubes or root trainers are better than small pots, but the deeper 9cm pots can be used if that is what you have.

You will probably find out sooner or later so I may as well tell you., it is remarkably fiddly to fill tubes and compost does tend to go everywhere. You can either put the tubes in the container and try and fill them in situ (this does mean you get a lot of compost in between but that’s not a bad thing, the roots are likely to come through the cardboard before you come to plant them out) or put the tube into the bag of compost and fill it there, keeping a hand over one end.

I always used to say sow two seeds per tube because most sweet peas germinate at around 65%. However, my seed has proven to be so good, I think I am going to say one seed for each tube. Sweet peas do like space and I am never going to thin out a perfectly healthy sweet pea seedling. I am just not that person.

It is important to make sure the seed is not buried too deep. You are aiming for about a centimetre. I find dibbing with a pencil and dropping the seed in is incredible satisfying, but it is hard to keep track of the depth and everything sinks again when you water. Filling with compost to very nearly the top and then adding the seed and covering is safer in terms of knowing how deep they are, but also doesn’t compact the compost.

Label.

Label each of the tubes unless every single tube in the container is the same variety. I know, I have tried to get around this will saying that ‘from this row is Jilly’, or ‘this is half Nimbus and half Burnished Bronze’.  I promise you that when spring arrives, all this means is that you have a lot of identical, unidentifiable plants.

Water very gently but very thoroughly. When I say gently, the water will bounce out of the container and splash everywhere, particularly when the compost is dry. Do it in a sink or outside. I haven’t found a way of doing this without water spurting off in strange directions so I just accept that it will and take precautions. The first water should be quite a comprehensive one as it takes the place of the soaking step that we have missed out (if you have) and there needs to be enough moisture in the compost to soften the seed coating.

The mantra to remember for most seeds, but particularly sweet peas, is:

warm and dark for germination, cool and light for growing on.

Around 15 degrees Celsius is about right according to the experts but I think a kitchen windowsill, or any place out of a draft indoors, is fine.

Keep them moist but not wet. Once the shoots are up and through, get them out in the cold. If you molly coddle them, you get weak, leggy plants.

Once the plants are 4–6 inches tall, pinch out the central growing tip, just above a leaf joint, leaving just two or three leaf nodes. This will encourage the plant to branch vigorously from the base. If they are growing really well, it might be worth putting the individual tubes into a pot.

Next steps for sweet peas

Hopefully, your sweet peas have made it through the winter, and they are starting to put on a bit of growth in the spring. You will probably have realised that you have grown far too many and now you need to decide where to put them. There are generally two questions at this stage. Ground or pot? How are you going to support them?

Growing sweet peas in containers

It absolutely can be done. Every year, I make a point of having a pot in the back courtyard with just Piggy Sue in it just I can sit next to it when I eat my breakfast and I can look out on it when I am doing the washing up. However, the pot is big. All peas have long tap roots, and all peas are hungry plants, so I wince when I see five sweet pea plants crushed into one small pot. You might get the odd flower from them, but they will never live a happy life. My pot is an old metal wash tub from the tip shop and it is at least a metre tall. This is no time for terracotta. Fill it with best peat free compost you can get your hands on and be prepared to feed.

Planting out

Sweet peas are surprisingly hardy so, although the advice is generally to wait until the last frost, it doesn’t matter if you time this a bit wrong. Sweet peas won’t die if you plant them out too early. What they will do is sulk. This is clearly my own projection; what they are actually doing is prioritising root growth over leaf growth but every year it catches me out. I plant out what I think are strong healthy plants, and they just sit there. Sometimes, this is because they have been planted over a mole tunnel and they hate this, but generally they are fine and I am fretting unduly.

Plant seedlings out after the last frost, roughly 8 inches apart, against a support, trellis or netting.  Tie them in to get them started.

Sweet peas are heavy feeders and require a little extra pampering to produce abundantly. Prepare planting beds by applying bone meal, a thick layer of compost or well rotted manure and a generous dose of natural fertilizer. They grow rapidly and require a strong structure to climb. Hazel teepees are perfect.

Sweet peas love water, and without consistent moisture they will fail to thrive. Keeping their thirst quenched during warm weather is crucial. Feed plants weekly with diluted seaweed emulsion.