Raised beds , how deep?

[starloc]

Im running out of space in the ground so ive decided to make raised beds, theres no soil left to dig so i need raised beds , this is to be ontop of tiles, water should drain out fine as the floors not exactly level!

I want to grow , mini carrots ,Mini turnips ,onions and shallots, how deep do they need to grow , do i need to use multipurpose compost or will cheapo mushroom compost work? , should i add something like perlite to aid drainage?

[deezyb]

hi starloc...3 of my raised beds (on top of gravel) are 6/7 inches deep and I remember that I filled them with multi purpose compost with a mix of manure initially...and I've topped them up this year with rotted down leaves (mixed into compost). Your veg will be fine...the main issue will be to keep the compost full of nutrients year after year.

D

[Alice]

Hello Starloc, what what you want to grow 4 -5 inches of depth should be fine. Make sure you have good drainage by making sure the water can run out round the bottom. I wouldn't use perlite - there should be no need. I don't know anything about mushroom compost but you will need to feed your plants with something. Good luck.

[bazzaboy]

Starloc, I doubt you'll need perlite to improve drainage as I suspect a bigger problem might be retaining moisture if it's a hot summer (I live in hope...). So on that front probably best to try it and then decide what's best -e.g. it might be that something like vermiculite (which claims to aid water retention) or, depending on size, the water-retaining crystals used for baskets and containers, might prove appropriate. Is your tiled surface completely impermeable? If so do bear in mind that run-off will carry with it soil/compost/whatever (i.e. it won't drain as clean water). You sound very fortunate if you can get cheapo mushroom compost (wasn't someone asking t'other day what had happened to it all?), I'd be inclined to make up my own mix including it. Filling raised beds can get pricey but if the opportunity arises I'd tend to maximise the potential capacity/depth at this planning stage (within reason) even if I don't fill it to the brim first year but leave room for some additional compost later... e.g. onions don't need any great depth for their roots but if its too shallow on a hard impermeable surface the whole bed will dry out in a few hours sun... And how big's a mini-carrot? Hope it works! b.

[greendean]

mmmmmmmmmmmmmmmmmmmmmmmmmmmm

[starloc]

Ive ended up doing some of these, well i have the bits for 4 of them, but only made one, i keep the citrus trees on pallets to keep the pots dry, so toay i chucked the citrus off and put brick under the citrus instead
The pallets, now have decking boards from b+q , 2 of them to each pallet, costing about 5.00 , i glued it all together with a waterproof contact glue i make at work, then i stained it on the outside,
The bottom of it has a piece of corrigated plastic sheting to keep compost/moisture in and i added tiny holes punched in all over it to add some drainage if needed.

It took 180L of compost in it



Im going to make some twice as deep, about a foot or so to do bigger carrots, will a foot be deep enough for normal size carrots?

[Snadger]

Methinks your going to be doing a lot of watering through the tropical summer we've been promised!

[starloc]

Im thinking of adding some water tubes with a valve for each raised bed, i can go round and look whats dry and what isnt, open the required valve for each bed and then turn the water on them all, sprinkling through tubes on the surface
I have loads of fruit trees in pots so i usualy need to water them every day in the summer as well, maybe i should just fit sprinklers and soak the whole lot like in a nursery.

[FionaH]

Im thinking of adding some water tubes with a valve for each raised bed, i can go round and look whats dry and what isnt, open the required valve for each bed and then turn the water on them all, sprinkling through tubes on the surface

Bed looks great. Valves and tubes? sounds very clever to me

[Flobalob]

I find it worthwhile to tack a plastic membrane to the inside of the timber used for raised beds. Nothing fancy,used compost bags are fine. Will prolong the life of the timber.

[starloc]

I left the sides as the were, they were the decking boards and looked very very hard wood , possibly treated with something, the bottom of it is the pallet, ontop of the pallet i used polyethylene cardboard sheet (like the stuff house signs are made from) , the sheeting should keep the moisture off the pallet

That one is now full of onions,I planted them a bit close, I will take some out as they swell up to make room for the others