im due to be planting up (and building!) my raised border beds in a week or so they're going to be dug low, covered with a thick weed proof membrane (recommended by garden centre - it's like a woven pvc type stuff) and filled with top soil, miracle grow compost and ordinary compost so in all the plants should have 10-12" of root space then covered with a thinner weed barrier. I'm planting amongst other things bamboo (2 tiny 1 medium) and Rosemary do I also need to put any root feeding fertiliser like bonemeal or anything down?
Even if the miracle grow is 'watered down' with top soil (both bagged and 'real') and ordinary compost?
So as I understand it... You are going to dig down. Put down a liner. Fill with soil, and then put down another membrane? Tbh, I don't really see the benifit of the liner at the base. If the plants want to put down roots, then this is going to restrict them. And will possibly also affect the drainage.
You're spot on, I've got issue at the moment with ivy and brambles, and although I've dug them out as best I can the garden centre advised a weed barrier liner at the base of the bed to help prevent them coming back through, it's dewitt weed liner I think if that helps at all
Yes, the plants need a chance to put their roots down and settle in before being given any more feed, there will be enough in the soil to sustain them for a couple of months at least.
I wouldn't use the barrier. It will cause more problems than it solves. If you look at the photos of my garden in your other thread. There is a piece of derelict land behind the fence. Fence full of ivy and brambles, and on the land behind. I just cut back or pull out if it encroaches on my space. But it's easily controllable.
I always think of bonemeal as a long term fertiliser, so yes it wouldn't. hurt to add some I be inclined to use mostly good topsoil, be careful what you buy, it might contain weed seeds. I'd also be very wary about the fabric at the lower level, it will stop the plant roots getting a decent hold into the soil, causing problems in dry years, and stability of tall plants..