[mad mark]

Has anyone put raised beds down on tarmac? Is it okay will the veg grow. I have put down one area with stone walls around it and dug up the tarmac where the small walls are and grew spuds in it last year but wondered if I did another one with timber would I need to dig up the tarmac? Any thoughts out there? I only have a small garden with my chickens in and a couple of veg beds but have a large tarmac area outside the back door for up to five cars to park on which is a waste really when it comes to green living.....
I have a couple of small plastic greenhouses for starting my seeds off in on this land.
Thanks for your help.

[coo!]

suppose it would just be like a giant grow bag! just make sure put something at bottom for drinage, saying that they would have to be quite deep for soil and drainage. i would give it a go what could it hurt!

[muddywellies]

I would say go for it too. I would imagine it working best for something like salad leaves rather than, say, carrots and parsnips. Unless you are planning on making them incredibly deep! I have a book by Charles Dowding called 'Organic Gardening the Natural No-Dig Way' which covers raised beds in detail. He's constructed them on top of paving before. I'd really recommend this book. Good Luck! 

[Babstreefern]

I've seen this done before on a TV gardening programme, but it was done over concrete, and what the chap did was drill holes down through the concrete, so you would have to do the same.  This acts as drainage.  But don't forget that tarmac is oil based, so I don't know if it would affect the plants that you're growing.

[mad mark]

Thanks for the advice. I will have a go with another raised bed, I might drill through the tarmac to get some drainage going. I will put in salad leaves as we eat loads of that during the summer and they grow well in front of the house in the direct sunlight. If if put down a black weed liner thingy then no tarmac contamination.

Lets hope we get a summer and some sunshine.

Cheers thanks for that folk .

[paintedlady]

I wouldn't have thought drilling was necessary unless you were using sealant on the bottom of the timber frame to stop water from escaping altogether?  Gravity alone in the raised bed should ensure the water drains down and out, and if you had any concerns, I suppose you could always put a layer of gravel or sand on the bottom before adding any soil/compost on the top?

[tam]

How about holes an inch up the side of the raised bed? Might be a bit easier than drilling through tarmac (depending what your making the beds out of).

[mad mark]

What do you reckon is best to make raised beds out of? Pallet wood is a bit on the soft side and hardwood is expensive and difficult to find in skips. I read about scaffolding planks but struggling to find a source. I am in Derbyshire Peak District  if anyone has any suggestions for sourcing wood for raised beds. Dont really want to spend money as I haven't any!!!

[Ice]

I went for the easy option and used gravel boards for mine.  I have one made from pallets that has lasted three seasons and is now showing signs of age.

[mad mark]

What are gravel boards? Sorry to be thick......
Cheers

[Ice]

They're the boards you see at the foot of wooden fencing.  I get mine from Wickes.

[senrab_nhoj]

They're the boards you see at the foot of wooden fencing.  I get mine from Wickes.

cheapest place for 'em

[mad mark]

Thanks for that will take a trip to Wickes when I have some funds and get making some more raised beds. What is the best deal for compost, soil at the moment any suggestions???

[sunshineband]

B&Q 4 bags for a tenner

[Trillium]

If you check out Garden Girl on U Tube, you'll see that she's put her raised beds directly onto tarmac without any drilling. Tarmac is naturally a bit uneven regardless of how carefully someone leveled it, so there would be seepage from the bottom. If anything, I'd suggest you use tanalised lumber for the bottom layer of boards so any rotting is limited for a considerable time. If you're still worried, then drill a few drainage holes low on the bottom boards of the bed.