onion sets are beginning to bolt

breezyacre · Posted: Tue Jun 16, 2009 4:50 pm Post subject: onion sets are beginning to bolt

Am just noticing that the onion sets I sowed during march are beginning to bolt here and there. I planted some red onion sets in the tunnel and they are also beginning to bolt. I have been pulling the bolting shoots away. Is it time to loosen the roots so that more of the growth goes into the bulb I wonder. Seems early to be doing that however. Any thoughts on this would be gratefully considered. Cool

ian · Posted: Tue Jun 16, 2009 6:06 pm Post subject:

I have had same problem this week I pulled seed heads off some and folded leaves down on others to see what works, it's a matter of saving what you can at this stage i think.

michael brenock · Posted: Tue Jun 16, 2009 6:20 pm Post subject:

Bolting in onion sets is caused by a number of factors, some of which are outside of your control. They are usually heat treated after being harvested and dried and stored at a low temperature regime around 3-4 deg until they are planted. If they were stored at high temperatures for more than 3-4 days then they will bolt when they are planted. If they were properly stored and planted early started growing and then were subject to a cold spell they would tend to bolt. Bolting is very common this year and is more than likely due to the cold spell after a warm spell. it is a futile exercise pulling off the seed heads to encourage bulb swelling. I have a few bolters myself and got sets from different suppliers. Earlier planting yields bigger bulbs but increases the risk of bolting.
michael brenock horticultural advisor (retired)

Liparis · Posted: Tue Jun 16, 2009 7:49 pm Post subject:

I agree with Michael. A bad habit I've seen this year is onion sets on show in tubs outside the shop door, in full sunshine. Very bad practice. They need cool and dark.
As for removing the seed heads, you will probably find your onions aren't much use for eating either. That seed head comes up from the centre of the bulb, and oh boy, it can be a tough old thing, even after taking the flower head off. In some cases you may have to pressure cook the middle of the onion for a week or two to make it tender. I just dump bolted onions. I also never plant my onions before late April, seldom get them bolting, but I get reasonable onions.
Bill.

breezyacre · Posted: Wed Jun 17, 2009 7:54 am Post subject:

Thanks to all. Therefore to recap. Buy the sets early and store them in the cool and dark. Wait until april to sow. Probably better now to discard the onions that bolted as they will be tough and sour.

Liparis · Posted: Wed Jun 17, 2009 9:10 am Post subject:

barremic · Posted: Wed Jun 17, 2009 9:28 am Post subject:

Quick question re the onions. is it worth it to try and collect the seeds.
I have one onion from last year which i never pulled, and i am curious about the flower etc. so i am just letting it grow. but is it possible to collect the seeds from onions that are bolting?

Thanks

Liparis · Posted: Wed Jun 17, 2009 9:54 am Post subject:

It is, many exhibition growers do just that. Depending on the breeding of yours, don't expect the same type of onion, but no reason you won't get decent useable onions. Sow seed in heat after the shortest day and grow on before planting out when frosts pass and the young onions have been hardened off.
Bill.

barremic · Posted: Wed Jun 17, 2009 10:54 am Post subject:

Thanks Bill

Something new to try next year!

michael brenock · Posted: Wed Jun 17, 2009 12:17 pm Post subject:

re raising oniond from seed I do it every year in cellular trays 8 seeds per cell, usually reds and after hardening off i transplant them out in May. saving your own seed from the flower head of the set should be alright but remember that these varities were bred specially for set production ie to produce a bulb in their second year of growth. in the forties a variety called james's keeping was a popular variety for this purpose.
michael brenock horticultural advisor (retired)

barremic · Posted: Wed Jun 17, 2009 1:37 pm Post subject:

So it would be two years before those seeds would produce a bulb/onion?

I know they are cheap to buy, but its nice to try something new every now and then

thanks for the advice

Liparis · Posted: Wed Jun 17, 2009 1:53 pm Post subject:

Not quite. You will maybe get a good sized onion or you may get a smaller onion, no way to tell until you try it, but hey! small onions can pack a powerfull flavour punch.
Bill.

barremic · Posted: Wed Jun 17, 2009 2:37 pm Post subject:

Any tips you might have on drying the seeds etc, it seems to be not quite open now, and green. Is this when i grab the seeds?

Sorry for all the questions

breezyacre · Posted: Wed Jun 17, 2009 2:47 pm Post subject:

my father used to grow James Keeping for years and then they seemed to disappear from the market. Is there a good alternative for growing onions from seed that anyone would recommend

Liparis · Posted: Wed Jun 17, 2009 5:00 pm Post subject: