[SusieB]

I think a bean pit is chucking your kitchen waste in a hole, to plant your runner beans on later.

Is this the same effect as using already rotted compost.  Why is it done?  Any tips?  What sort of area (I think I mean do the roots spread far)?

Thank you

[JayG]

In my case it's done when there's no room left in my daleks, and the purpose is to help retain moisture at the roots - runner beans don't like being short of water.

Runner bean roots don't spread far laterally, so the trench doesn't need to be particularly wide - depth-wise, it partly depends on how much waste you are planning to bury, but 18" is probably as deep as most people would want to dig. When the trench is more or less full (doesn't have to all be done at once), put the excavated soil back on top. There will of course be a mound but it will settle in time as the material rots down underneath it.

Only use vegetable waste - you will probably find your trench re-excavated for you if you include animal waste! 

[SusieB]

Comprehensive answer, thank you.

[Mum2mj]

When is the latest month you can add raw veg waste to the trench?

[JayG]

I plant my beans out late May/early June so I aim to cover up the trench by the end of March - my soil is very light though, you may need to give a trench in heavier, wetter, colder soil a bit longer to settle down.

[Mum2mj]

I plant my beans out late May/early June so I aim to cover up the trench by the end of March - my soil is very light though, you may need to give a trench in heavier, wetter, colder soil a bit longer to settle down.

Thanks JayG I also have light soil

[Ivor Backache]

the purpose is to help retain moisture at the roots - runner beans don't like being short of water.

For this reason I first put an inch of newspaper in the bottom of the trench.

[mumofstig]

Yes, papers and any cardboard boxes I can lay my hands on - tear them up and mix them with the kitchen waste etc. It all helps 

[AussieInFrance]

Cardboard boxes/cartons with a plastic coating are not recommended. And remove any tape or labels before using. Otherwise, recycle it all whether it's under straw as a path or weed suppression around the plot.

[DD.]

It's a good way of getting rid of brussels sprouts stalks - chopped up a bit, of course.

[New shoot]

I don't grow brussels, but the sweetcorn stalks go in (roughly hacked up), plus cabbage stalks and all my household compost scraps of veg, paper and card.

Beans don't need very fine soil to grow in, so it is a good way of getting rid of the allotment waste.  I also use bean pits for my squashes, if I have enough waste to make extra trenches 

[mrsbean]

Thanks for the tip about squas

[mrsbean]

Sorry meant squashes.