Paul Taylor wrote:

Most books I read on planting pototoes say they need earthing up -

Not always true. Earlies, and varieties like Pink Fir Apple, don't much
like being earthed up, and you don't increase the crop that way. You
certainly should earth up most other maincrop spuds. If you don't earth
up, use a black polythene mulch (a couple of layers) to avoid getting
light on tubers close to the surface.

however as I only have limited space I want to plant the rows closer
together which means I can no longer earth them up.

Unfortunately, this won't increase the crop from maincrops. You'll just
get smaller spuds. Again, rules differ for Fir Apples and waxy earlies:
these you can cram into a smaller space and still get a decent crop, but
read on....

To counter this I am
considering planting the seed pototoes deeper. This seems to make sense
to me (but I'm not a vastly experianced gardner!). Could anyone please
comment on this as a reasonable sensible technique - or do spuds really
have to be earthed up.

You can do this, but I suspect you'll have to start earlier in the year.
I've found that deep-lying spuds I've accidentally failed to lift have
set haulms even earlier than conventionally-planted seeds, presumably
because they've had a head start by being there overwinter, so I imagine
that you could deep-plant seed spuds earlier and get a similar effect.


The one thing that you're guaranteed to find if you plant spuds too
close together, regardless of variety, is that you'll multiply the pest
problem massively. Slugs in particular will be a major hassle, and
blight and other diseases can jump far more easily plant to plant if
they're close enough to touch, or share spores etc. There's no point in
trying to increase your crop by say 30% if you lose the lot to blight or
slugs.


All in all, I'd suggest planting at the conventional distances, earthing
up the ones that like it, and just accepting you'll get a smaller total
crop. If you're really strapped for room, grow earlies instead, and put
in a rotation (perhaps a legume, for nitrogenation, or a root crop like
radish or carrot for speed and succession) after they're finished.


Jon
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