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Confusing info' re: onions sets (planting conditions)

Hi all,

I'm totally confused by the conflicting advice about ground preparation for planting onion sets I'm receiving from the RHS and Gardeners World (I thought that they worked closely together).

I've just read in my "Gardeners World" mag the basics of crop rotation. For Plot 4 "Onions and Roots" it advises "Don't add manure or other organic matter to the soil. Fork through to loosen the soil and lightly firm down . Don't add lime or high nitrogen fertiliser but do apply a phosphate feed."

R.H.S. advice.

 Onions do not thrive on acid soils (below pH 6.5). Reduce acidity by applying lime in autumn and winter.   Apply two bucketfuls of well-rotted manure or other organic matter such as garden compost every square metre (yard). This will help add nutrients, improve the soil structure and hold moisture. Little fertiliser is required at planting, apply 35g per sq m (1oz per sq yd) of Growmore or twice as much organic fertiliser such as dried poultry manure pellets. If you cannot apply organic matter – use more fertiliser, up to twice as much if the soil is poor.

I've been working my allotment for about 20 yrs and I more or less apply one of these methods (I'm not saying which just yet). So unless recommended growing methods have recently changed I don't know which advice to believe!

What say you?



  • fidgetbonesfidgetbones Posts: 14,703

    My best onions are grown on soil that has well rotted fym added in the winter before planting, calcified seaweed added instead of lime, and then blood fish and bone added before planting. It works for me.

    You don't stop doing new things because you get old, you get old because you stop doing new things. <3
  • Hostafan1Hostafan1 Posts: 26,165

    I'm tempted to say , if MD is giving advice contrary to RHS , I'd got with RHS.

  • ObelixxObelixx Vendée, Western FrancePosts: 22,159

    RHS for me too.  

    Their experts all have training and experience and experiment with different varieties and growing conditions to be able to give the best advice.   They've only been exchanging and developing gardening expertise since 1804 and do change their advice according to new research, new products, new varieties, new social conditions such as the drive towards being wildlife friendly as well as changes resulting from government and EU policies on garden chemicals and products for gardeners.


    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • DovefromaboveDovefromabove Central Norfolk UKPosts: 64,446

    Think we're looking at two different things - if using a rotational plan the section where onions are to be grown will already have been manured for the legumes and limed for the brassicas in previous rotations - that should be sufficient for the onions - adding manure to that section will not suit the root crops which would be grown with the onions when working to a rotational plan.  

    That's how a basic crop rotation for a vegetable garden works - the planting conditions are an accumulation of what has gone before.

    If starting from scratch and not using a rotational plan, then add manure.

    The advice does not conflict - just different ways of providing the same conditions. image

    “I am not lost, for I know where I am. But however, where I am may be lost.” Winnie the Pooh

  • ObelixxObelixx Vendée, Western FrancePosts: 22,159

    Sound analysis Dove but I don't do strict rotation as I don't grow the same crops every year.   I've given up on carrots and parsnips and don't do spuds.   I did onion sets and spring onions for the first time in several years and have had a good crop.  

    Kohl rabi turned out to be a good new experiment for me this year.   I always grow some broccoli and kale, fennel and assorted salads and make sure they're not in the same bed as the year before.   This year I also have radicchio and leeks and there are permanent rhubarb, currant and raspberry, blackberry and loganberry beds.  They get compost every year and I grow pumpkins at their feet..

    When more of the veggie beds are clear I need to start a new strawberry bed for 2017's crop.



    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • Thanks for all the comments,

    I don't usually add manure to my onion beds but I do add garden compost. I add fertilisers in an incremental way. Starting with a little bit in autumn and building up throughout the following months, adding the most in April and up to May.

    I use a high Nitrogen fertiliser early on to develop as many leaves as possible, (as each extra leaf means an extra onion ring) and supplement this with a phosphate rich fertiliser later on to build up the overall bulb size.

    As i said earlier I been doing this for years and have usually had very good results.

    Thanks again for the comments


  • BLTBLT Posts: 525

    I found the biggest onions I ever grew ,were grown over a trench with poulty manure about 6 inches deep..  I have just put in my sets and this time its a combo of well rotted horse manure  and topsoil with pelleted poultry manure raked into the surface and then planted up with sets..  You will always get differing methods, just do what works for you.

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