[siggy_7]

Hello all, this is my first post on the forum!

I have an allotment which I took on last year, which has grown nothing but a very healthy crop of brambles, grass and stinging nettles for a number of years. Having spent most of the last year with glyphosate and a spade, this year I'm growing a variety of crops for the first time in the soil (having only done a few potatoes, beans and squashes last year). My soil type is a fairly heavy clay on a slope (free-draining in places) and seems to be fairly devoid of much organic matter for the most part. I didn't get the chance to dig in any organic matter over the winter, so about a week ago I got hold of some 15-15-15 NPK fertiliser to apply as a top dressing (25kg for £11 from Mole Valley Farmers - don't go to a garden centre if you need some) and applied at a rate of about 50g/m2 which I thought I'd calculated as a fairly heavy but still acceptable application rate. The butternut squashes I was planting out immediately died back (some look completely dead, others are bravely hanging in there with some yellowing of the leaves). I hoped it was just the squashes and not related to the fertiliser, but watering last night I've noticed some yellowing at the leaf tips of almost all my crops in a few places - carrots, parsnips, potatoes, runner beans, sweetcorn, brussels, cauliflowers and broccoli. This is pretty conclusive evidence I think that my crops are suffering to a greater or lesser extent from salt stress brought on by too much NPK. So my questions really are two-fold:

1. Did I really apply that much fertiliser?!? What would a better application rate have been?

2. Is there anything I can do now to alleviate the salt stress where it's occurring?

[ben]

Welcome to the forum.

I'm afraid you must only apply NPK (I assume it was small pellets) a couple of weeks before you plant/sow anything and it must rain afterwards, else it tends to burn/scorch the plants.

I'm not sure what you can do to fix the problem ... perhaps a lot of water to try to dilute it all.

[siggy_7]

Yes, it was pelleted NPK. I thought that you could still apply compound fertilisers as a top dressing? In arable farming (where I have some experience), we certainly apply nitrogen to growing crops. I've been watering quite heavily over the last few weeks (except for the couple of days at the end of the week before / beginning of last week where we had some decent rain) so hopefully continued watering might help. Thanks for your reply.

[gillie]

You have set me thinking.  I have certainly applied NPK pelleted fertilisers to grassland without any ill effects but your veg do seem to have been upset by it.

I remember that you should not apply lime at the same time as pelleted fertiliser as it cancels out the effect.  Since you seem to have overdone it a bit, how about adding some lime now?  I would use calcified seaweed if I could get it, which will add some useful trace elements at the same time.

Cheers,

Gillie

[Yorkie]

I wouldn't advise liming - for a start, it will affect the pH of your soil and you don't actually know whether it's alkaline or acidic at the mo anyway; it could prevent the plant taking up other nutrients; and, most importantly, applying lime and fertiliser close together actually tends to cause a chemical reaction in itself - which the plants are unlikely to like 

[siggy_7]

Thanks for the advice, I'm a little nervous about doing yet more damage with a lime/fert reaction so I think I'll just stick with the watering and hope the majority pull through. Some of the squash are definitely toasted I think but hopefully a few of the healthier looking ones will come back! Will let you all know how I get on.