[sparky]

Some schools of thought say that when planting potatoes make a trench and fill with well rotted manure plant the potatoes on it then cover with soil.
Jerry the "head gardener" on our plots has said no, plant the seed spuds in the ground and cover with the manure as potatoes grow UP not Down.
Any thoughts?

[Ice]

Shoots go up, roots go down.  So I believe he is wrong, but what do I know? :?

[WG.]

Roots don't go down very far though.  Hence my post on container planting : http://www.chat.allotment-garden.org/viewtopic.php?p=160830#160830

[gobs]

Some schools of thought also say: dig a spade deep trench, put some well rotted manure on the bottom, sit your potatoes on it and fill up trench.

Really, they grow both ways.

[Trillium]

Potatoes are those exceptions to the rule. They do grow both ways which is why you must hill them up regardless of how deep you plant them. Believe me, I've tried the latter. I suspect they're warmth oriented and insist on reaching for the surface.
However, doing the trench and manure is still good for potatoes. We manure and rotate their spot every year and have never been disappointed.

[gobs]

And also outwards. A good distance between rows is very important for earthing, up 2-3 feet, you need a lot of space with larger varieties.

[coatesi]

The reason for trenching potatoes is to get your earlies going when the soil is still cold.
  Trench, fresh horse manure, 2-3" soil, spuds, 4" soil, done !
  The manure warms up as it rots and gives the spuds a kick start.
 Me dad and then me, total 60yrs believe me it works. Nothing is completely new.
coatesi

[WG.]

There you go sparky - a different take on it.  Fresh rather than rotted manure.

Now your only problem is when to do it so that the haulm doesn't get burned by frosts.