I've not grown onions before, so I'm a bit unsure as to the main difference
for sowing onion sets as opposed to seed?

Any advice appreciated

Ros
(in the south of England)

I grow onions from sets and seed,and there is really no difference for
me in the outcomes.I am not sure there is any difference between them
as regards bolting or ability to withstand downy mildew(which was very
bad last year).
Onion sets are becoming expensive to buy,and there are a limited
number of varieties available.

The main season for growing onion sets is planting them in Feb-March
and harvesting them in August-September for use and winter storage-a
good variety is Sturon which keeps well.

The second time is to plant autumn onion sets in Sept-Oct,when they
overwinter as small plants, grow rapidly in the Spring,and are ready
to start eating at end of May.So they are earlier than the
spring planted sets and are particularly delicious if you start
pulling them when about the size of a table tennis ball.They are often
called Japanese onions.

Seed sowing for the main crop is carried out in mid March
outside.However I start mine off in a greenhouse in mid January by
sowing in 4" pots with a little bottom heat at a temperature of about
10C.Mine are just beginning to germinate after about two weeks or
so.On a cool window cill would be just as good.When the seedlings are
about a couple of inches tall,I very carefully plant them into modules
(24 per tray),keep them on heat until growing on,and then put them
somewhere cooler and finally into a cold frame.After a while outside,I
plant out the seedlings in late March.Varieties I grow are Ailsa
Craig,Bedfordshire Champion and Red Baron.

If you wish to become really keen you can grow your own sets,which I
did for the first time last year.Sow the seeds outside in late May-
thickly- harvest in September,and dry out very carefully in somewhere
warm.I use our boiler house.The trick is to harvest before they become
too large.

Hope this helps,Michael

Ros Butt wrote:

I've not grown onions before, so I'm a bit unsure as to the main difference
for sowing onion sets as opposed to seed?

Any advice appreciated

Ros
(in the south of England)