Do I line raised beds?

longwalks1

We are planning 2 raised beds, built either from sleepers or even scaffold boards on their sides, stacked 3 high and strengthened internally.  Would i need to line them inside with a thick liner, and holes at the bottom for drainage?

conradmum

Lining the sides with plastic sheeting will help the sleepers or planks last longer. Personally, I wouldn't bother putting anything on the bottom and would allow the bed to drain directly into the soil. A lining on the bottom with holes will help to retain water in the bed but it might also become waterlogged. Most plants and vegetables don't do well in soggy soil. Do be careful the sleepers or scaffolding planks haven't been treated with creosote because it's harmful to plants. 

Caitykinss

I have raised beds built from decking boards, which seemed to be the cheapest option last year. They have open bottoms, to make the most of the added depth of the ground - particularly useful for root vegetables that need more space. I did a 'no-dig' approach of lining the bottom with cardboard to suppress the grass and weeds, and then filled with compost/soil/manure/whatever you need. Just topped up with a couple of bags of compost this year. The sides aren't lined, but are painted with weatherproof fence/outdoor paint. How long they'll last I don't know, but they were very cheap to build and are holding up well so far.

As conradmum said above, you want to avoid limiting drainage and the bed becoming waterlogged. Lining the sides might not be a bad idea to protect the boards, but the only reason I'd bother putting a bottom in is if I wanted to move them in the future, or if they were going on concrete/slabs rather than grass/soil. Essentially, do you want a raised bed or a big planter/pot? 

Farway

No experience of raised beds, but just recently I saw a programme where one reason given for lining the sides was to prevent "wicking" of moisture from the soil and through the boards / wood, thus drying out the beds more quickly than a lined bed with a membrane

Sounded sensible but maybe an urban myth, however I think that the added bonus of wood protection and you only need do it once would persuade me to do it should I ever go down that route

phoebe1989seb

We built some raised veg beds from oak sleepers in 2018. Didn't line them with anything, just filled with topsoil, manure, compost and top up as required each year.

Three years on, they have aged to a nice silvered timber  😃

gamston

i built raised beds last year i used tanilised timber with the inside covered with rubber roof membane i topped the tanilised timbers with 1" X 4" boards (this covered the rubber on top of the tanilised timbers and gave a drip tray to keeping water off the sides of the timber to stop rot)
inside i put matting to compost going into the garden soil, filled the bottom with branches & rotting wood covered with leaf compost

greenbee

I lined the sides of mine with empty compost bags, and the bottom with weed membrane. As it is very deep, I added stones for drainage, then branches, most of the contents of the compost heaps (only half cooked!), topsoil and compost. I also put seeper hose in, which connects to the waterbutt (or hose if that’s empty). It was well worth the effort given how dry it was last year. And how wet it is this year...