Growing Big Onions from seed

I think this RHS article is mustard ... (c) Puns-'R'-Us

My summary, unless you read it differently:

• If free lime / chalk is present all bets are off. (Test by pouring some Vinegar on to a small soil sample. If it fizzes that's bad news :( )
• Sulphur is the best agent for lowering pH
• (Aluminium Sulphate more commonly used for Blue-ing Hydrangeas, it will lower pH but repeat/heavy application will build up Aluminium in the soil)
• Sulphur application is not effective when the soil is cold, so apply in Spring because:
• Sulphur has to react with soil microbes which form Sulphuric Acid, which is what lowers the pH
• Heavier application (e.g. 2x) will be required on Clay soils, compared to Sandy ones
• The finer the Sulphur the quicker it will act; "Sulphur chips" will be slow, compared to "Sulphur powder"
• Incorporate well into the soil (i.e. a simple top dressing will take ages to have any effect)
• Testing soil for pH should be done when chemicals, manure and fertilizers have not been recently applied (ideally wait 3 months) [I think it would be worth applying a modest amount, retest after a week or two, and then decide whether to add & incorporate more - "incorporate" will be easier if you have a Rotavator]

Source: http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=82

Thoughts:

• Sulphur is a natural fungicide. Will it interfere with beneficial mycorrhizal activity?
• Ammonium sulphate, used as a fertilizer, will also help - only any help if you need Nitrogen rather than (say) Potash, but it could be an excuse to "be generous" when you do! (
• Ammonium nitrate will also work, but is only half as good at acidifying as Ammonium sulphate, and Sulphur is 3x as good as
• Ammonium sulphate - but you don't get any Nitrogen fertilizer benefit, of course
• Different schools of thought on whether over-application matters, or not. RHS says to avoid that situation (by using "softly softly" approach).

 

Why Scrungee, have you tried growing them?

Steve...

 

Hiya Kristen.

An interesting read, that. Btw, you seem to have posted the same link twice. Right, what I think I'll do is do my manuring now, and add the A/S in the spring a bit at a time, testing as I go. Pretty much as you advisedI'll have to do the vinegar test first, of course. Thanks for taking the time to look it up

 

I just did the vinegar test, and.....it fizzes

 

Grown from Robinsons "Mammoth improved" onion seed this year. The heaviest weighed in at 1lb 8oz.



Grown outside in cultivated saturated soil but without feeding at all. The seeds where sown late (Feb I think) and planted out in a rush without any feed and left to get on with it. They where however hoed regularly.

I collected my seeds in person from Robinsons the autumn before (they are based near my Fathers house in Lancs), and on display was a pile of giant onions 2,3 & 4lbs+, some of the seeds growers attain 6lb+ with this seed.

Steve...

 

Thanks Steve,you never know i could be one of those 6lb growers....first time lucky eh

 

That's really slack, isn't it ? :(

:( So some calcium carbonate in your soil ... Chalk or Limestone - or perhaps just some Lime left over from when you limed it previously (how long ago was that?). If the last of those then you will be fine, over time.

Sorry, remind me: have your grown Onions before? Or is this about wanting to grow Champion Sized Onions?

If the former I'm inclined to suggest just planting them. No harm using the Sulphur anyway ... just it may not have much effect if there is Calcium carbonate in the soil to immediately return the acidified soil to alkaline ...

One of the articles I read about "acidifying your soil" said he poured Sulphuric Acid on his soil a couple of days before planting, because "Sulphur treatment takes too long" ... so I don't suppose some redundant Sulphur is going to matter.

 

Hiya Kristen.

I suppose the last time I added lime would have been this time last year? I only added to beds that were going to take Brassicas, so probably 2 beds.

Yes, I grow Onions every year, and yes, I had wanted to improve the soil to grow bigger Onions. But, it's not just about the Onions, I wanted to improve the soil for all my crops. I've been 'gardening' now for four years (veg wise)since I moved into my current home. The first thing I did was to put in some raised beds, ten in all. As there wasn't enough 'fill', I added bought in (bagged) topsoil, as sold at B&Q. The first years crop was really good, I actually surprised myself. Since then, year on year, the crops have been in decline, relatively speaking. It's got me thinking that the soil in the raised beds is 'normalising', and reverting back to the background PH.

 

Yes, you could be right about it reverting.

However, if you are putting plenty of Manure on that should be sufficient to keep it at a reasonable pH.

The Lime that you put on may have been unnecessary in the past, so that might be contributing? (in the sense that if you stop liming now the beds will not get more alkaline, and it will be down to the manuring etc. to lower the pH)

I've never tested my soil, just assumed it was alkaline ... but I do put a lot of farmyard manure on it (well, not the root crops ... but the rest of it). Probably about 4" layer, on the surface, through the Winter, and then after that is incorporated in the Spring I mulch the plants, once they are growing, with more muck.

Are your adding manure at all?

 

Just got my 'Robinsons Mammoth Improved' seeds through the post they came with an interesting little booklet too

 

Hiya Kristen.

It's possible. I haven't actually Limed this year, I would normally do this around now.

Normally, I would manure probably one third of my raised beds very year, and I will do that again shortly.

I guess I'll just have to plod on with what I have, maybe go over the top a bit with the manuring.

Cheers...Freddy

 

Personally I'm not very fussy about these things, I don't have time to pay sufficient attention to the plants to get a first class crop, so I'm happy with "reasonably good", thus you may not be happy with that outcome - different-folk=different-strokes and all that.

But my thinking is that your soil is not hideously Alkaline (even including for the fact that you may have been over-liming it) so with the application of manure it should grow good vegetables.

Maybe we are looking in the wrong direction?

In comparing the last 2 years with the ones before I would say that last 2 years have not been as good for me for Onions. This year my Solar Panels have recorded 25% fewer kW (ytd) than (same ytd) in 2011, and I reckon that translates directly into Veg performance. I haven't got any figures handy for my Soar Panels in earlier years ... but I'm sure there are Sunshine hours available online (AND for your area, which would be better than my wet-finger-in-air!!)

Further thought: you could "send off" a soil sample for pucker analysis. That might reveal some nutrient deficiency etc. and would give you a really accurate benchmark - i.e. if you also used your own pH testing kits/meters against the same sample you'd know how accurate they were for future tests.

Dunno what a soil-sample test costs? Perhaps just a few tens-of-pounds?

 

Hiya Kristen.

When I said "crops", I was speaking in general terms, not just Onions. I did actually look into having a proper test, but couldn't find anyone that does it at first, but have just looked again and came up with this http://www.forestry.gov.uk/fr/INFD-79MDEX#prices So many tests! I would have thought that I need to determine my PH first, which I have a sneaky feeling is going to be around the 8.0 mark

 

Not sure worth just doing the pH test. Unless both the test-tube and probe tests are way-out it will only "calibrate" your tests for you. I think a more general test would eb helpful - to tell you if any of the macro nutrients are adrift.

I found this RHS one:

http://www.rhs.org.uk/Gardening/Advice/RHS-Advisory-Service/RHS-Soil-Analysis-Service

Its only pH and P,K & Mg (plus Texture and Organic content) ... not sure that's enough if you have a real problem. £25 ...

Here's their video on how to take a representative sample:

http://www.rhs.org.uk/Video/Advice/Soil-samples---collecting-for-tests

I'm pretty sure I have a mini-test-tube test here that does the major nutrients (rather than just pH). Ashamed to say that, despite good intentions, I bought it years ago and have never used it ... if I find it I will try it! If nothing else if you decide to have a professional test done you might want to buy a self-test kit and run it on the exact same sample and see how your results compare - if "close enough" you could just use a self-test in future.

The self-tests that I have just Googled for are for pH and N, P & K specifically and RHS says that testing for Nitrogen is not a lot of good as its level in the soil changes rapidly (it washes out of the soil). Magnesium deficiency is easily corrected with Epsom Salts, and it is important to plants (deficiency is common in Tomatoes as they start fruiting, as I'm sure you will have seen) so the inclusion of that in the RHS test seems a good bet.

I found this article interesting:
http://www.gardenadvice.co.uk/howto/organic/soil-tests/index.html
talking about us gardeners putting way too much phosphate/potash on our soils (and the side effects that can cause). I have read that before, and in fact stopped using Bone Meal, but it might be that I should not be using fertilizers with a Zero in the appropriate N:P:K ratio-value!

Dunno about customs duty from USA, but this test seemed good:
http://www.ebay.co.uk/itm/Luster-Le...in_0&hash=item2ec127308b&_uhb=1#ht_4962wt_906

 

For my pennyworth, I've never done a PH test and never intend to do so, if it grows it grows if not, then never again!

I take the ancient approach, spread manure in the autumn and come spring sow, suck and see? So far hasn't done me too badly!

Although I like to grow "giants" my main goal is to produce a decent nutritious crop for the kitchen.

We've had 2 very bad summers which haven't been conducive to veggie growing, let's give summer 2013 a chance to redeem our faith in our climate?