Advice on how to fill a planter

f_aidan

Hi all,

I'm looking for some advice.
I've just moved into a flat which has a small balcony area with two large fibreglass planters.
They are about 24cm deep, 30cm wide and 1.5m long, so quite big.
They sit on concrete and can't be moved.

They are currently empty and I'm just wondering the best way to fill them (i.e. soil/compost etc...), what type should I get? any old stuff from the DIY store or should I try to get some soil for a mix?
Also should I put some small stones at the bottom?

There are only four small holes which doesn't seem like enough so may need to drill for drainage.

I'd like to grow some herbs (parsley and the like), also have some flowers perhaps.

Many thanks.

BenCotto

I would be wary about putting soil in the containers because of the weight. Each container is 100 litres and wet soil is very, very heavy.

Stones in the bottom serve no function so I would definitely not bother. Instead I would use mostly Multi Purpose Compost, say 50 litres, plus 25 litres of John Innes no 2 and 25 litres of perlite or vermiculite. I’d stir into the mix 250 grams of slow release fertiliser pellets. If you’re environmentally conscious choose peat free compost. Otherwise I would research composts which do well in trials. Clover and Bord na Mona/Growise are two but not commonplace. Otherwise maybe Jack’s Magic. The best peat free composts are Melcourt SylvaGrow with added John Innes and Westland New Horizon.

Drilling extra drainage holes sound like a good plan. Put a J cloth on top of the holes to stop compost falling through.

Next season you might want to scrape away the top few inches of compost and replace it but, even if you don’t, add another 250 g dosage of fertiliser pellets (they’re normally sold in see through plastic jars)

When I grow parsley I just buy one of the already growing pots sold in the supermarket and bung it in. It never fails.

Dovefromabove

I agree with @BenCotto ... use good multi purpose compost rather than soil as it’s much lighter.  A lightweight alternative to stones for drainage at the bottom of containers us to break polystyrene packaging into chunks and use a layer of that. 

Loxley

Another weight saving drainage trick is to fill the bottom with upturned plant pots crammed together, fairly small ones would be best as you want to have some depth of soil. Or upturned plastic seed / bedding trays. You can usually pick them up for free if you are passing a traditional garden centre, or check Freecycle/Gumtree.