Friday, 9 March 2012

Testing the allotment soil pH.

I only went down the allotment to get some soil samples to do some tests and found that a big pile of horse muck had been delivered.

Well you cannot miss out on something like that so I have spent two hours getting a few barrow loads of muck and putting them onto the black currant (Ribes nigrum) bushes as a mulch.  This keeps the blackcurrants growing well and the ground moist.  I also put some horse muck onto the rhubarb (Rheum raponticum), whilst other people put custard.

The Champaign rhubarb is throwing up some good petioles and leaves under the black bins but the Victoria is still asleep.  The horse muck might warm the ground and encourage the Victoria to make more of an effort.

The Nemaslug nematodes (Phasmarhabditis hermaphrodita) have come and I am keeping them in the refrigerator at the moment.  I am hoping to put them onto the ground tomorrow - Saturday.  I have enough to do the leaf and roots bed; the peas and beans bed and the brassica bed.   I have used this very successfully for about four years now.

Now, the problem is that I have green manure growing on two of these beds and brassicas on the other.  I will want to dig the green manure in and at least fork where the brassicas are.  If I put the nematodes on now will I cause them a problem when I dig the ground over?  I don' t really think so especially if I dig very shallowly.   Forking should not cause any problem at all.  I will not have to do any digging or forking for a couple of weeks yet because the ground is still a little cold to put plants out. 

Having said that I will be planting the sweet pea seedlings as soon as the cane supports have been put up.  

The nematodes will have time to start their work before I start to disturb the soil.  

I have transplanted both Brassica oleracea var. capitata  "Golden Acre Primo" ; Brassica oleracea var. botrytis "Clapton" (Club root; Plasmodiophora brassicae resistant) and Brassica oleracea var botrytis "All the Year Round, into three inch pots to bring them on.  I still have a lot to do on the brassica bed before I plant any of these out.  I still have some February sown onions to plant as well particularly Allium cepa var. "Vision" which is supposed to be high yielding and can be stored for most of the winter.  I will plant these in sectioned trays.  

I still need the leeks, celeriac and the celery to germinate.  They are taking their time.   

So, why have I decided to test the soil on the allotment? 

I have used a lot of X Cupressocyparis leylandii shreddings dug 600mm deep in the soil as a kind of Hugelkultur and they are reported to be very acidic.  I want to know if they are causing the top soil to be acidic. I am going to put lime on some of the beds  this year particularly on the brassica and onion beds anyway, but I might need to put some on the other beds too.  Most vegetables grow well within the range of pH 6.5  to 7.  I will be able to find the allotment soil pH  quickly with a simple  test.  

However, it would also be good to know what the major nutrient potassium, phosphorus and nitrogen levels are and whether they need to be altered in any way.  The test I have bought should give me an idea of the nutrients in the soil too.  I don't have very much confidence in these test but they might give me a rule of thumb nutrient level.  

I need to demonstrate that I can use a simple soil test for the RHS practical gardening course so I might take a few photographs while doing the test.  I need some distilled water to do it with and I will be able to get some from the college - I hope.  

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