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Hampshire, UK

My previous soil sample was so alkaline that I am now buiding the mother of all raiseds bed on top of it. The results of my soil sample also suggested that it was fairly nutrient deficient and so I thought I might as well fertilise it with some inorganic fertiliser before putting the raised bed on top.... much easier now than later!

Soil analysis gave recommendation of using Triple Superphosphate (P2O5=46). This is proving difficult to get hold of although I can easily get Ammonium Metaphosphate (P2O5=52 & N=12) from a local farmer. Can I just substitute the Triple Superphosphate with the Ammonium Metaphosphate at a slightly lower dose rate or is it not as simple as that? Are there any other problems with using Ammonium Metaphosphate? (I am also adding Sulphate of Potash at recommended dose rate)

Thanks, Malcolm

10/30/2006 3:23:23 AM

Hampshire, UK

See http://www.bigpumpkins.com/msgboard/ViewThread.asp?b=20&p=170982 for soil test results

10/30/2006 3:24:39 AM

Sheridan . NY

malc-- the roots are still going to go down to the hi ph under you raised bed--i would suggest you bring down your ph with compost that is low ph or some thing acid--the compost will give you micnut also---as far as ferts above you must very big n p k problems----easy--rome wasnt built in aday----a lot of your n p k will be wash out if you put it on this fall----craig

10/30/2006 8:02:26 AM

Hampshire, UK

.....Except that the soil is alkaline because it has lots of chalk in it. It is FULL of visible white lumps. Making chalky soil acid just disolves the chalk, buffering it back to where it was. Having spoken to local farmers they say that makig this soil more acid doesn't work..... hence my 15 inch deep raised bed. Just thought I would do what I could to make the chalky soil more fertile for those roots that go down to it!

Could dig manure etc into the chalk but I thought I would rather put my efforts int making the bed as deep as possible.

The recommendation is to apply 150g/sq m (5.25oz/sq yd) Triple Super Phosphate and 300g/sq m (10.5oz/sq yd) Sulphate of potash.

Any further thoughts welcome!

10/30/2006 9:21:49 AM

Ctpumpkin@optonline.net

Triple Super phosphate isn't used much any more due to the lower analysis & also since it contains no Nitrogen. But old time book readers in some labs haven't kept up with the changing times & still recommend it.

Go ahead & used the AM.

I hope that mounded bed is deep enough to keep the AG roots satisfied & out of the chalk.

10/30/2006 10:33:48 PM

Cornwall UK.(50N 5W)300ft.

I think you mean mono ammonium phosphate there (MAP).
Don't see why you couldn't use it instead,up your way SCATS might have triple superphosphate or be able to get it.

A lot of us do have high nutrient levels in our patches often from the manure,comes as a bit of a shock when you see it as an all in one go inorganic dressing.

I can see where you're coming from with the raised bed nutrients from it will find there way down into the soil below eventually maybe not in 2007.Just remember that its a lot easier too add too much than it is to get rid of too much.

10/30/2006 11:06:04 PM

Mocksville, NC

This fall or now! Till in Gypsum, will help leach out, old ferts,ans salts, and depending how Alkaline ph Oranic Elementel Sulfer 1/2 pound per 1000ft2 per .05 to lower your ph then retest in Feb if you can.

11/3/2006 1:25:27 PM

Mocksville, NC

As stated above add compost, manure also if worms present in feb you nailed it right

11/3/2006 1:28:46 PM

Lymington

Hi Malc we used to use tripple superphosphate on the nursery as well as superphosphate and still may be able to get a bag for you from Fargro

12/6/2006 11:25:58 AM