Sowing seeds

Yes and no.the advantages are:
1 less disturbance of roots at planting out time.
2 slightly less restriction of length of root.
3 You can examine root system for any problems

Disadvantages:
1 cost
2 Only one plant per rootrainer

I have never used them myself so cannot comment on how good or otherwise they are.
I have always used pots either 5" (6 seeds) or 3" (2 seeds) and never had any problems.
My usual advice to anyone is that if it works for you use it.

If you already have rootrainers then why not sow some in them and try other methods and compare. Certainly if you are not intending to grow loads then use your rootrainers. (Might be a bit of a hassle if you wish to grow several hundred plants)

Thanks SP

I do have some rootrainers although they are getting a little battered now and as I've never tried SPs in pots I will do as you say and try some in each

Now, WF.

For August plants sow now and over the next couple of weeks.

I would rather sow indoors with GENTLE heat and as soon as the first shoot appears breaking the surface of the compost get them out into the cold frame. leave the top on for a couple of days and then leave open to the elements only covering again if torrential rain or hail.
The main thing is to allow full light and that will help to prevent legginess. Also to grow without any mollycoddling. What you want is to have short stocky plants.
If you are growing for garden display then by all means stop after the first or second pair of true leaves have formed although they will usually develop side shoots without stopping.
remember that the leading (first) shoot will not develop and that it is from the side shoots that you will use to grow on.

You will probably find that the later plants will be more prone to mildewing same as culinary peas so be prepared to spray in good time to help prevent that. (more on that subject later)

hi Scrumpy and welcome to the forum.
Always good to hear other growers viewpoints which I would say that if you asked 50 growers their methods you would probably get 50 different answers.
I think I said somewhere that if a particular method works for you then stick to it. By all means try other methods as there are no hard and fast rules regarding cultivation methods, just that some ways work for some but not necesserily others.
I learnt to grow sweetpeas by following the advice from the undisputed master of sweetpea cultivation and breeding, Bernard R. Jones
Many of his methods have been changed and/or adapted by others with success on the national scene but as I experienced my own successes following his methods I stick to them.
Probably the main difference in my own methods these days is the use of a cultivator to assist with ground preparation but other than that I tend to be a bit of a traditionalist.

Yes, we all have our different methods.
Heres a good one from Cooltanagh for people to read

www.cooltonagh.plus.com/sp_prn_files/advice/index.html

Having a complete change with my varieties this year and growing a few of theirs to see how they do.
My biggest problem occurs after layering in July, they always struggle after that, so i'm going to try sowing in mid March for the first time to see if they are any good for August shows and grow them down the allotment.